Historic Building Conservation Dissertation Examples

The IHBC has enjoyed a long-standing partnership with conservation courses across the UK, encouraging training and professional development in built and historic environment conservation in line with established national and international practice standards, including those from ICOMOS and the World Bank.

As part of our charitable services supporting conservation practice, we offer an independent cost-free ‘recognition’ programme for conservation courses. This entails a desk-top assessment of course content, submitted to us by the course providers, against the conservation philosophy and practice areas used to accredit and regulate IHBC members.

Courses are listed below, and details of its operations are described HERE

The IHBC’s recognised course listing is a unique resource that both offers quality assurance in terms of course content and learning priorities, and serves as a support to help prospective students target their individual practice needs and priorities. The listing does not assess the operation of the courses listed or their delivery, as these matters change regularly and are best overseen by the host organisation.

Copyright: University Of Portsmouth UK, September 2001

By: K.S. Kamal


Portsmouth is one of the national importance and a major tourist centre. It has a rich legacy of buildings and monuments with outstanding craftsmanship and architecture quality. Together they form an impressive historic features and heritage of the past works of man. As documents of the past, historic buildings are important as a source of historical materials used by historians. It is important to conserve and preserve historic buildings because it provides a sense of identity and continuity in a fast changing world for future generations. Most of historic buildings in Portsmouth are privately owned and according to English Heritage, some of them were at risk from defects. These buildings are not being well cared for due to the high cost of repair and maintenance. It was estimated that one third of the output of the building industry (£2,000 million per year) is for the restoration and repair of historic buildings. Meanwhile recent estimates by the Property Services Agency, one fifth of the total costs of restoration and repairs is spent on the rectification of defects in historic buildings arising from various factors. Research about problems of defects, deterioration, repair and maintenance of historic buildings is important to minimise the cost of restoration and to protect historic buildings from being lost forever. The Society for the Protection of Ancient Buildings saw the need for a guide to study about defects in historic buildings and aid the correct diagnosis because prevention is better than cure. Something has to be done to reduce the frequency of defects by choosing appropriate approaches, methods, techniques and materials. The overall aim of this dissertation is to have specialist knowledge associated with defects in historic buildings. Meanwhile the overall outcome of this dissertation is to be able to recognise and diagnose defects at each building element in historic buildings because there are so many defects that occur at various locations with different type of caused and symptoms. By studying building defects, it is hope that it could make good economic sense to historic buildings as defects concern society at large due to possible danger such as collapsed and loss of use. There is no reason why historic buildings if restored in a sympathetic manner, should not become an attractive building as a valuable and desirable asset for the owner.


My sincere thanks to my supervisor Mr. Keith Chapman for his invaluable help. His guidance and encouragement has made this dissertation a reality. I am also grateful to my course leader Dr. Robert Otter for his assistance, guidance and advice me in finishing this dissertation. My appreciation to all lecturers, Dr. Ray Riley, Mr. Bernard Webster, Mr. Tim Goodhead, Mr. Roger Tyrell, Mrs. Celia Clark, Mr. Kevin Stubb from Bursledon Brickwork, Mr. Peter from Treadgold’s Museum, librarians, owners of historic buildings and Portsmouth City Council for their helpful thought and in getting all the information and data for my dissertation. Lastly my appreciation and my thanks to my beloved wife Lela, my son Carl, Assoc. Prof. Dr. Rosman Ahmad, my sister Ain, UiTM staff and lastly to all my friends and family in Malaysia for their support morally, spiritually, financially and sharing all the difficulties with me in completing this dissertation. Thanks everyone for making my dreams a reality.


Ancient Monuments Society.
APT Association for Preservation Technology.
ASCHB Association for Studies in the Conservation of Historic Buildings.
BRE Building Research Establishment.
BRS Building Research Station.
BTA British Tourist Authority.
COSIRA Council on Small Industries in Rural Areas.
DOE Department of Environment.
DSIR Department of Scientific Industrial Research.
ENTCC Edinburgh New Town Conservation Committee.
HCPD Hampshire County Planning Department.
HMSO Her Majesty’s Stationery Office.
IIC-CG International Institute for Conservation-Canadian Group.
NAO National Audit Office.
NBA National Building Agency.
NMR National Monument Records.
NPA National Park Authorities.
PSA Property Services Agency.
RIBA Royal Institute of Building Agency.
SPAB Society for the Protection of Ancient Buildings.
TRADA Timber Research and Development Association.



Historic buildings according to Fielden (1996:1) “…is one that gives us a sense of wonder and makes us want to know more about people and culture that produced it. From the first act of its creation, through its long life to the present day, historic buildings have artistic and human messages, which will be revealed by a study of its history. A complexity of ideas and of cultures may be said to encircle historic buildings and be reflected in it”. Portsmouth has a rich legacy of historic buildings and monuments. Together they form an impressive heritage of the past works of man. As documents of the past, historic buildings are important as a source of historical materials as the paper and parchment used by historians. More than that, according to British Tourist Authority (BTA, 1980:6) they are “…living documents of the social and economic development of the country”. Historic buildings have immense value for tourism and a recent reports by a House of Commons Sub Committee concluded, “…the national heritage is the single most important aspect of Britain that attract tourist”. Therefor it is important to conserve and preserve historic buildings because it provides a sense of identity and continuity in a fast changing world. With increasing standardisation there is much to admire in the variety, craftsmanship and beauty of historic features in these buildings. Portsmouth is one of the national importance and a major tourist centre. It is famous for its naval, military and defensive architecture with outstanding quality. The fortifications of Portsmouth and its harbour dating from the 16th to the 19th centuries are unique and the remains of the 17th and 18th century town defences of Portsmouth are without parallel in Britain. Of equal importance are the Naval Dockyard buildings with a fine legacy of naval and industrial architecture which besides having a history of shipbuilding and maintenance stretching back at least seven hundred years, had a manufacturing aspect which has produced a remarkable collection of industrial buildings such as Block Mills, Great Ropery, Iron and Brass Foundry, Smithery, etc. The Block Mills, erected in 1800, housed Marc Isambard Brunel’s rigging block machinery, generally accepted as the first application of machine tools for mass production. All these historic buildings are important and need to be conserve and preserve for future generations. Meanwhile according to Hampshire County Planning Department (HCPD), Portsmouth towns were timbers framed until the latter part of the 17th century. Nevertheless the vast majority of buildings were still constructed of timber and, particularly in the countryside, timber framed houses survive by the hundred. It is safe to say that the great majority of surviving timber framed buildings in Portsmouth date from the 16th and 17th centuries. Good timber framed buildings of the 16th century can still be seen; for example in Peacock Lane and Lombard Street, though they are concealed behind later fronts. Buckingham House in the High Street is timber framed but was altered and refronted in the late 17th or early 18th century. (HCPD, 1979). According to a research carried out by County Councils and National Park Authorities in England and Wales, there are over 500,000 historic buildings in England and it represents only a small proportion, perhaps two percent of the total building stock. Most of the historic buildings are privately owned and not being well cared for due to the high cost of repair and maintenance. (National Audit Office, 1991). The onus of keeping a historic building in good repair referring to Haskel (1993:121) “…must rest in the first place with the owner, but there will be instances where an owner is not liable to, or declined to attend to repairs to his listed property with the consequence that the buildings condition, and hence, its listable qualities are at risk of being lost forever”. In 1990-91, English Heritage has carried out a sample survey to determine the extent of the problem. With assistance from survey teams from both County Councils and District Councils, English Heritage surveyed some 43,000 of England’s 500,000 historic buildings and concluded that, whilst most were in reasonable condition, some 36,700 or (7.3%) were at risk from defect and deterioration. This number could be doubled if historic buildings found to be vulnerable and in need of restoration and repair were to be included. Not surprisingly the survey by English Heritage found that, whilst over half of all historic buildings are in conservation areas designated to preserve or enhance their character and almost two thirds of those historic buildings categorised as ‘at risk’ were not in conservation areas. Norfolk City Council for example has published a survey of historic buildings at risk in their county and found that over two hundred historic buildings are suffering from neglect and decay. (Michell, 1988). Meanwhile referring to Portsmouth City Council, there are over six hundred buildings registered in the list of buildings of historical or architectural interest. In total they contain a wealth of historic buildings, particularly cottages, villas, terrace houses, theatres, churches, cathedrals, warehouses, barracks and naval buildings developed from about the sixteenth and eighteenth centuries. Although Portsmouth cannot boast many large castles or stately homes, nevertheless it has a wide variety of buildings of interest and its own specialities. Particularly noticeable is the variety of traditional building materials, reflecting the varied geology of the county. Here one can find timber framing, brick, flint, chalk and cob for walls; tile hanging, weatherboard and plaster for cladding and finishing; thatch and plain clay tiles for roofs. Some materials were imported like stone from Normandy and Isle of Wight, slates from Devon and Cornwall, imported in large quantities and have been with us for so long that they might also be described as traditional and should also be restored and well kept from defects. (HCPD, 1979). It was estimated that one third of the output of the construction and building industry is for the restoration and repair of historic buildings; the current rate of expenditure from all sources amounts to at least £2,000 million per year. Some of this is for the repair and cleaning of historic buildings and some for replacement of materials having a relatively short natural life in comparison with the life of the historic building. But a proportion and recent estimates by the Property Services Agency (PSA) of the Department of Environment (DOE) indicate that it may be as much as one fifth of the total costs of restoration and repairs is spent on the rectification of defects arising from various factors. (DOE, 1974). If the cost due to loss of property is then added to the actual cost of restoration and repair it becomes clear that the elimination of ‘avoidable’ defects must give valuable financial benefits and should be a major priority. At no time in our history as mention by Grafton (1972) cited by Insall (1972:7) the chairman of the Society for the Protection of Ancient Buildings (SPAB), “…has there been such an obvious and increasing interest in historic buildings and at no time there has been such a need for knowledge in dealing with the problems of defect, decay, repair, maintenance and rehabilitation, or for the continuance of essential crafts and the study of new materials suitable for use in historic buildings. Much has been studied and written on the history of architecture but little by comparison on the defect and repair of historic buildings”. In 1957, on the occasion of the 80th birthday of the SPAB, the Architects Journal has encourage people to do research about problems of defects and repair to historic buildings therefor it can be made available for use by all those who concerned with the care and protection of historic buildings. (Powys, 1981).


The overall aim of this research is to have specialised knowledge associated with defects in historic buildings like; to determine the locations, types and causes of defect so that specific action can be carried out to overcome the problems as described before. Meanwhile the overall outcome of this research is to be able to recognise and diagnose defects at each building element in historic buildings. Previously much has been published about building defects, their causes and cures, but unfortunately the information is scattered over a wide range of publications and not easily accessible. There are also a number of excellent texts, studies and research conducted on building defects but these tends to be either highly technical and/or specific to certain type of defects or building materials and did not cover on the overall elements of the buildings. Moreover, the published advice on remedial work often assumes that the cause of the failure is already known; in practice, although the symptoms will be apparent, the underlaying factors may be obscure. If a wrong diagnosis is made, the treatment is unlikely to be successful and money will be wasted. The Committee on Building Maintenance, in the course of its investigations for the government, saw the need for a guide to study about the defects and aid the correct diagnosis of defects because prevention is better than cure, and something have to be done to reduce the frequency of defects especially to historic buildings by choosing appropriate approaches, methods, techniques and materials. Therefor it is worth to do this research. There are three primary objectives in this research that need to be fulfilled to ensure that the overall aim of this research is achieved. The objectives are as follows:
1. To recognise the locations of defects at historic buildings.
2. To determine the types of defects at historic buildings.
3. To identify the causes of defects at historic buildings.

Basically this research will attempt to cover all the above objectives.


The approach used in this research starts with the overview of historic buildings in Portsmouth and problems related to defects in historic buildings. This is followed by literature review on the defects and historic buildings. The literature review is mainly acquired from published books, research papers, seminar papers and journals. The research is further reinforced by formulating a set of questionnaires and handed over to owners or occupants of selected historic buildings in Portsmouth. The questionnaire once return from the respondents, will be tabulated, summarised and analysed accordingly to the research objectives to obtain findings. The background information of this research is obtained by various methods and the collection of new data is necessary to get the accurate result. The data regarding defects in historic buildings is collected by four main methods as follows:
1. Observations through site survey where data is obtained from a visual inspection of defects at its exact location.
2. Questionnaires as mention before where data is collected by preparing a series of structured questions related to defects in historic buildings and given to the respondent.
3. Oral information where data is obtained from the building’s occupant regarding the defects.
4. Recorded information where data is collected from the previous reports on defects that have already been produced.


Chapter one will gives the general introduction about the background information and presents the overall contents of the whole research. It introduces the subject area, subject matter and context of study. Later on it proceeds to issues, situation of problems, relevance and interest that need to be discussed which leads to the research of this topic. The aim and objectives of the research is clearly outlined with approach in conducting the research and the research methodology employed to achieve them including the areas of study. This chapter concludes with the structure of the research. Meanwhile chapter two will discuss on the history of defects in historic buildings. It provides the detailed information about the background of the research. Then it will explain the history of the problems, necessarily and influences that has led up to the point of the research. It will also identify the boundaries of the area of research that is to be studied, and the gaps in existing coverage of the subject matters. This chapter will also review about the related organisations, legislation background, financial, restoration and repair approach. It will validate the legitimacy of the research, limitation of the study and suggestion that has been made from other studies, comments on accepted facts and different authors opinion on the related subject matter.
Followed by chapter three, which will determine the diagnosis, causes, locations and symptoms of defects that normally occur in historic buildings. The description of each problem is organised and described in detail based on the elements of building to make it easier to be understood. Various figures and tables associated with defects in historic buildings are also included in this chapter to give a clear view about the subject matter. Chapter four will analyse the data collected from the questionnaire form in the context of the research and present the result and findings in forms of tables, graphs and charts. The result will attempt to fulfil all of the research objectives. Lastly chapter five will conclude the overall findings and bring the strands from all the chapters discussed before. Recommendations will end up this research followed by suggestion and some guidelines for further research about approach to restoration and repairs work to historic buildings since the locations, types and causes of defects is established in this research.


This chapter will briefly review about the detailed background information related to defects and historic buildings. It will also review the related organisations, legislation background and financial problems and aid. Lastly it will describe the restoration and repair approach on defects in historic buildings. Various comments, facts and authors’ opinion is also included in this chapter.


Historic buildings according to Fielden (1996:1) can be defined as “…buildings that has architectural, aesthetic, history, documentary, archaeological, economic, social and even political and spiritual or symbolic values. If it has survived the hazards of one hundred years of usefulness; it has a good claim to being called historic”. It can also be in any form of buildings like terrace houses, public house, theatre, cinema, school, railway station, shops, warehouse, fort, castle, barracks etc. By its nature these man made heritages is fine and because it is open to decay and deterioration, is likely to get smaller. (DOE, 1955). The restoration of our historic buildings demands wise management of resources, sound judgement and clear sense of proportion. Perhaps, above all, Marshall (1998) suggested that “…it demands the desire and dedication to ensure that our historic buildings is well preserve and free from defects and deterioration that can slowly damaged and destroy the historic buildings itself”. As Fielden (1996:7) expressed “…the need of modern long term restoration policy is necessary and should concentrate on fighting the agents of defects and deterioration in historic buildings”. Historic buildings according to Davey (1988:1) should be treasured for their beauty and for their historic associations where “…as long as they fulfil the purpose for which they were designed, their fabric is likely to be well maintained and free from any defects, but if the historic buildings ceases to have a useful or appropriate function it is liable to be neglected, abused and ultimately demolished, ignorance and indifference also put historic buildings at risk”. Protection therefor depends on control over the use, alteration and demolition of historic buildings, on a general appreciation of their importance, and on an efficient policy of maintenance and repair as highlighted in Edinburgh New Town Conservation Committee (ENTCC, 1980), cited by Davey (1988:1). According to Fielden (1996:7), “…historic buildings have the qualities of low energy consumption, loose fit and long life, so the lessons learned from their study are relevant to determine the defects that occur at most historic buildings”. This opinion is support by Hinks (1997) and Building Research Establishment (BRE, 1974) where the technology of building defects is important and must be understood as a whole by people who are involved in restoration of historic buildings. Reference is also made in a number of textbooks on defects in historic buildings as National Building Agency (NBA, 1989:9) expressed that “…repair is an expensive item to historic buildings and it requiring careful attention from building owners, occupiers, contractors, surveyors, architects and in fact every active member involve in restoration of historic buildings, therefor the correct diagnosis of building defects associated with the correct remedial action is the only economic basis for successful maintenance and repair programme”. This research is designed to help diagnosis and give an indication of the remedy for the situation discovered.


Since the war, rapid residential, commercial and industrial development together with vastly increased motor traffic that produced air pollution has put historic buildings and its fabric severely at risk. According to HCPD (1979:61), “…literally hundreds of historic buildings have been lost since the war, especially in towns where the pressure for reconstruction and redevelopment were greatest. The majority of these buildings never had any statutory protection and it was the growing public concern over the continuous loss of historic buildings due to lack of maintenance and high rate of defects that occur at these buildings”. As well as the unfavourable reaction to what replaced them, has led to significant changes in the law in 1967 to protect the character of historic buildings through designation as Listed Buildings and Conservation Areas and in 1968 by bringing historic buildings under proper statutory control”. Defect according to BRE (1983:85) is defined as “…a shortfall in performance occurring at any time in the life of the product, element or dwelling in which it occurs. Defects in historic buildings occur for a variety of reasons”. Meanwhile Eldridge (1976:1) expressed that “…defects can be repaired satisfactorily only if its’ cause has been correctly diagnosed; experience has shown that errors are too often made and sometimes it happens because it is not possible to obtain all the relevant information, but more often it is because the symptoms have not been fully investigated or the information has not been correctly interpreted”. Research published by BRE (1974) mention that a correct diagnosis depends upon the collection and assembly of all information likely to be relevant. Meanwhile Richardson (1995:1) expressed that “…it is not unknown for remedial repair works to be specified which had an effect opposite to what was in fact required; thus errors may not be only expensive and ineffective but on occasions may actually aggravate the defect, making more extensive repair works necessary”. Many of the expensive repairs are due to neglect. Once the defect has been put right, as Davey (1988:15) says “…historic buildings should be kept in good repair. Many repairs previously are postponed because of expense and even though postponement never saves money and usually increased the cost. When all proprietors budget for future repairs and regular maintenance the prospects for historic buildings will be greatly improved”. The period since the Second World War has seen not only a rapid development of the technology of restoration but also a matching development of the philosophy and ethics of restoration. (DOE, 1971). The restoration of historic building referring to Weaver (1993) has thus developed into an extremely complex process involving a team of many professionals, specialist, trades and craftsworkers. For an example, in the 1970s a number of specialists, who had trained primarily in the United Kingdom and Europe, worked on the development of the restoration work of historic buildings and sites for the Canadian Government. They developed an organised approach to the management of restoration process that has been a major Canadian contribution to this field. Many of the best conservators also follow conservative practises involving the use of traditional and well proven technology and materials which is known as the ‘tried and proven’ technologies, (IIC-CG, 1989) cited by Weaver (1993:1).


In United Kingdom (UK), public interest in conserving and restoring historic buildings is so many sided, and is maintained by so many different organisations, that no account would be complete which did not attempt to give a concerted picture of them. According to Insall (1972:31-43), public bodies whose concern is with the care and preservation of historic buildings fall from the architect’s standpoint into three clearly defined classes. Firstly, there are the official advisory bodies, maintained to advice on technical problems, and to whom reference may be made. Then there are the private bodies, equally qualified and able to give specific technique advice. Thirdly, there are the charitable bodies, whose funds enable financial assistance to be given, take over and administer historic buildings and help to preserve them. A number of official bodies that can advice on the technical problems involved in restoration and repair works is like ‘The Building Research Station’ that has a special advisory service on a wide range of problems affecting old as well as new buildings; ‘The Council for Small Industries in Rural Areas’ was founded in 1921 and is an advisory service set up by the government to assist, runs or arrange courses in restoration work; ‘The Forest Products Research Laboratory’ that will examine infected timber samples and give a firm diagnosis of fungus types in cases of doubt; ‘Institute of Geological Sciences and Geological Museum’ advises on the geological aspects of buildings and decorative stones where the institute can determine the rock type used in any particular building and can give advice on matching of stone repair; ‘The Royal Commission on Historical Monuments (England)’ is a government agency employing some forty specialists in its work of recording monuments county by county and all the detailed records are held by the commissions which is also responsible for the ‘National Monuments Record’ (formerly the National Buildings Record); ‘The Council for Places of Worship’ (formerly the Council for the Care of Churches) is the central organisation for all matters relating to the construction, care and use of places of worship belonging to the Church of England; and lastly museums and libraries like ‘The Print Room of the British Museum’, professional and private organisations such as the ‘Society of Antiquaries’, the ‘Royal Institute of Building Agency’, the ‘Soane Museum’, and other local museums and libraries throughout the country, all have extremely valuable collections of information, often unpublished, including early prints and photographs, original drawings and manuscripts of varying authenticity, accumulated over a long period. Whereas the official organisations are mostly precluded from sponsoring individual causes, the larger private organisations often exist for the purpose of giving technical advice in which their aid may be sought like ‘The Society for the Protection of Ancient Buildings’ which is pioneer of all the private bodies and pre eminent in giving technical advice, was founded by William Morris in 1877, where the society has pioneered the idea of annual short courses for architects in the care of historic buildings and to ensure the continuance of informed technical knowledge in traditional methods of restoration and repair; ‘The Ancient Monuments Society’ was founded in 1924 for the study and conservation of ancient monuments, historic buildings and fine old craftsmanship and also makes small financial grants to assist projects of special interest; ‘Council for British Archaeology’ provides liaison at national level between archaeological societies and the government bodies concerned with the preservation of ancient monuments and historic buildings, including those of the industrial revolution; ‘The Georgian Group’ was founded in 1937 and deals with problems affecting buildings erected since 1714, and the aims include the creation of interest in Georgian architecture, giving advises as to the preservation, repair and use of today Georgian buildings, and their protection from destruction and disfigurement; ‘The Victorian Society’ founded in 1958 has sought to convert unfavourable public opinion towards Victorian and Edwardian design (1830-1914) and the primary task of the society is to ensure that all major Victorian and Edwardian buildings receive protection under the Town and Country Planning Act 1971; ‘The Council for the Protection of Rural England’ was founded in 1926 to organise concerted action to secure the improvement, protection and preservation of the countryside and its town and villages. ‘The Association for Studies in the Conservation of Historic Buildings’ with aims to keep members informed of current practice in the conservation of historic buildings and monuments, and to give close study to training methods in the techniques and philosophy of building conservation; ‘The Conference on Training Architects in Conservation’ with its main pre occupations are in seeing that all architectural education provides an appreciation of historic buildings and their care; ‘The Institute of Advanced Architectural Studies’ which is primarily concerned with the technicalities of preservation work by running short residential courses on the protection and repair of historic buildings; and other societies interested in particular building types such as ‘The National Association of Almshouses’; ‘The Windmill and Watermill Section of SPAB’; and civic, amenity and local societies like ‘The Civic Trust’ which is an independent body, founded n 1957 meanwhile in the field of public conscience like the ‘Local County, Civic, Archaeological and Preservation Societies’. There are said to be over 100,000 private trust and societies administering trust funds like ‘The Charity Commissioners’ which is responsible in giving advice to trustees; ‘The National Trust’ founded in 1895 with aims are the permanent preservation for the nation’s benefit and enjoyment of land of special natural interest beauty, and of buildings of national, architectural or artistic importance; ‘Pilgrim Trust’ that has always devoted a large part of its resources to the preservation of the national heritage of architectural and history; ‘The Mutual Households Association Ltd.’ with aims to save large county mansions from demolition and decay; and other society such as ‘Incorporated Church Building Society and Friends of Friendless Churches’ with aims to secure the preservation and restoration of churches and chapels in the UK.


According to Insall (1972:11-13), in 1944 (under Sections 42 and 43 of the Town and Country Planning Act) and again in 1971 (by Section 54 of the new Act) the nation required the then Minister of Town and Country Planning to compile list s of all buildings in this country considered to be of architectural and historic interest. Until the first listing was completed in 1968, it was difficult to achieve any balanced general picture, or to relate the merits of any particular building either to changing local land use, or to the conflicting aims to other historic buildings elsewhere. The responsibility for the listing process rests with the Secretary of State for the Environment. The principle of selection was drawn up on the advice of an expert committee of architects, antiquaries and historians, and these are still broadly followed. In choosing buildings, special attention is paid to good examples of a particular architectural style or piece of planning, or good illustrations of social or economic history; technological innovation; association with well known character and events; and group value. Early in 1970, these criteria were modified. It was decided to give a higher priority to buildings of group value, and to include good examples of planned layout as well as more examples of Victorian architecture. In practice, any building dating from 1700 is now listed automatically. Most buildings of 1700-1840 are listed, although selection is necessary. Between 1840 and 1914 only those of definite quality and character are listed, and these would normally include important works by principal architects of the day. A start is now being made on selecting building dating from 1914 to 1939. At present, there are two grades of buildings that are listed in this way for statutory protection. Grade I Buildings of such importance that only the greatest necessity would justify their demolition; Grade II* Buildings of exceptional quality which are not quite eligible for Grade I; and Grade II Buildings of considerable historic or architectural importance which have good claim to survival. A third grade, which was known sometimes as the Supplementary List, has now been discontinued. This comprises mostly buildings of group interest. When listing was completed for the first time in 1968, there were in England and Wales 4,351 buildings listed as Grade I, and 111,300 as Grade II* and Grade II, making a total over 115,000 on the statutory list. A further 136,752 were earlier included in the old Grade III or Supplementary List. All buildings included in the statutory lists now enjoy immediate protection under the Town and Country Planning Act 1968, from demolition and alteration. In March 1977 the Secretary of State issued Circular 23/77* which sets out national policy and procedures relating to historic buildings and conservation areas. The advice contains in that Circular forms a basis for the local authorities policy statement and is used as essential reference for all those involved in conserving the national heritage. The Secretary of State message is clear as “…if we do not take steps to protect and preserve historic buildings of value, either in their own right or because of the contribution they make to a pleasant townscape or village scene, they may well be lost, and once lost, they cannot be replaced. Historic buildings and conservation areas are vitally important to the environmental quality of life in this country. Buildings of architectural and historic merit should receive very special attention” (Historic Buildings and Conservation Areas, Policy and Procedure, DOE Circular, 1977) cited by (HCPD, 1979:14).


Historic buildings according to Hargreaves (1964) “…cost more to maintain than modern ones and need special, often expensive materials, special knowledge and trained craftsmen if they are to be properly restored and repaired”. His opinion is support by Richardson (2001) where “…money for restoration and repairs is nearly always hard to come by, especially for the owners of historic buildings. Balanced attention to repairs by their relative urgencies will enable the most to be done with a small budget”. As Clark (1979:2) expressed “…the repair of historic buildings is primarily the responsibility of their owners and yet there is a great public interest in seeing that historic buildings are kept. Unfortunately, finance is nearly always a serious problem in preservation work, and it is therefore important for the building owner to have full knowledge of the various ways in which money can be found”. Basically there are various systems of grants and aid for building owners like the County and District Councils make grants towards the costs of repair and maintenance of historic buildings of all kinds. The level of grant available referring to (HCPD, 1979:83) in the last few years has not only enable several hundred historic buildings to be repaired, but has also enable the local authorities to ‘tip the balance’ in economically marginal cases, saving the historic buildings which otherwise might have been lost. For example, the total cost of work grants aided between 1974 and 1979 amounted to nearly £2.5 million. Some of these grants have been made to historic buildings included in Town Schemes with the DOE joining the County and District Councils in contributing towards the costs of restoration works. Referring to Insall (1972:21-26), grants are available in certain circumstances both from central government funds and from local authorities. Under section 4 of the Civic Amenities Act 1967, the Historic Building Council (HBC) has the power to recommend the Secretary of State to make loans under the Historic Buildings and Ancient Monuments Act 1953 known as ‘Historic Building Council Grant’ for the restoration of historic buildings. Since the HBC was formed in 1953, grants totalling more than £7 million have been made on its recommendation. Meanwhile local authorities have a wider scope for making grants under the Local Authorities (Historic Buildings) Act 1962. The ‘Local Authority Grants’ are for any building of architectural or historic interest, whether it is listed or not. There are three types of grants under the local authorities which is the ‘Discretionary Improvement Grants’ that are payable at the discretion of the local authority; ‘Standard Improvement Grants’ on the other hand are obtainable by owners as of right; and lastly ‘Special Grants’ that are available for the improvement of houses in multiple occupation. In some cases the Secretary of State and the County and District Councils make grants jointly. This grant is called ‘Town Schemes’ and is for restoring the whole groups of historic buildings. Meanwhile the ‘Housing Act Grants’; the ‘Conservation Area Grants’; and the ‘Building Preservation Trust’ are for ensuring the continued preservation of historic buildings. There are also other grants from charitable foundations such as the ‘Pilgrim Trust’; the ‘Landmark Trust’; and the ‘Leche Trust’, all empowered to make grants for the repair of historic buildings. Lastly loans from the ‘Architectural Heritage Fund’ is set up to assist local historic buildings preservation trusts and other appropriate bodies with loan capital them to acquire and restore any historic buildings which merits preservation.


Restoration according to Braun (1954:1) is defined as “…returning the existing fabric of a place to a known earlier state by removing accretions or by reassembling existing components without the introduction of new material”. Meanwhile Fielden, (1996:9) expressed that “…the object of restoration is to revive the original concept or legibility of the object. Restoration and reintegration of details and features occurs frequently and is based upon respect for original material, archaeological evidence, original design and authentic documents. Replacement of missing or decayed parts must integrate harmoniously with the whole, and must be distinguishable on close inspection from the original so that restoration does not falsify archaeological or historical evidence. In a sense, the cleaning of buildings is also a form of restoration, and replacement of missing decorative elements is another”. If restoration are well carried out, than there would be far less need for repairs or renewals. In William Morris Manifesto of 1877, establishing the SPAB, he enjoined ‘stave off decay by daily care’ as cited by Fielden (1996:218). This policy can only be made to work on a basis of regular inspections. The following standard of ethics as suggested by Fielden (1996:6) is, “…it must be rigorously observed in restoration work like the condition of historic buildings must be recorded before any intervention; historic evidence must not be destroyed, falsified or removed; any intervention must be the minimum necessary; any intervention must be governed by unswerving respect for the aesthetic, historical and physical integrity of cultural property; and lastly all methods and materials used during treatment must be fully documented”. As Fielden (1996:6) further expressed that “…any interventions should be reversible or repeatable, if technically possible; or at least not prejudice a future intervention whenever this may become necessary”; not hinder the possibility of later access to all evidence incorporated in the object; allow the maximum amount of existing material to be retained; be harmonious in colour, tone, texture, form and scale, if additions are necessary, but should be less noticeable than original material, while at the same time being identifiable; and lastly not be undertaken by conservators or restorers who are insufficiently trained or experienced, unless they obtain competent advice. However, it must be recognise that some problem are unique and have to be solved from first principles on a ‘trial and error’ basis. Once the original materials have been thus treated and damaged the processes are found to be irreversible and the products cannot be removed without destroying the very resource, which was to be preserved (IIC-CG, 1989) cited by Weaver (1993:2). The successful restoration and repair of historic buildings requires compatible materials to match the original as closely as possible. According to Davey (1988:14) “…the use of unsympathetic materials can result in a marked change in the appearance of the buildings; a shorter life for all or part of the building; and lastly a ‘sacrificial’ deterioration of the surrounding original material, e.g. the injudicious use of cement is well known as a contributing factor in the decay of stonework”. To guard against the harmful consequences of insufficient knowledge leading to a misuse of technology, as Weaver (1993:1) suggested that “…the professional conservators and restorers should adopted the codes of ethics and guidelines which are in themselves a mark of the growing maturity of their profession”.


This chapter will briefly describe about the diagnosis, causes, locations and symptoms of defects that normally occur in historic buildings. The defects can be divided into tables based on building elements so that it would be easier to be understood. This chapter endeavours to give some guidance and a better understanding of the defects itself because in historic buildings, there are many defects that occur at various locations with different type of cause and symptoms. Defects in historic buildings concern society at large due to possible danger posed and or loss of use of the building by occupants. They often also incur high financial costs in term of conservation and repair work. Therefor by determining its causes, it is hope that action can be taken to prevent it from happening at the earlier stage in the future.


Defects diagnosis is simply a logical way of proceeding from the evidence of the cause of defect, after which remedies can be prescribe. According to NBA (1989:10), “…diagnosis of defects is simple and can be based on common sense as much as any profound knowledge of building technology”. The first step is to gather information or collection of data. Information can be obtained from visual inspection of the defect at the surrounding area of the building elements. Sometimes site tests and laboratory examination of samples of materials is necessary. Everything that would appear to be relevant should be observed and recorded. A close inspection of the affected area should be made. There are many instruments that can be used to diagnose defects and records of the data like binoculars, portable tape recorder, camera, triple lens magnifying glass, tell-tales, moisture meter and other relevant equipment. Always remember that it is better to have more information than not enough. Much information can also be obtained from the occupier of the building, especially regarding the history of the defect. All oral information should be recorded as statements made for later confirmation if necessary. Efforts should be made to see the recorded information such as drawings, maintenance manual, specification and any reports on the defect, which have already been produced. Having obtained as much information as possible about the building and the symptoms of the defect it is then necessary to compare the symptoms. Symptoms that appear to be similar may have different causes and some defects may have more than one cause contributing to them at the same time (Richardson, 1995:16).
1. Sulphate attack in brickwork caused by slow burning boiler and unlined flue and resulting in distortion of stack.
2. Split lead to roof thatch caused decay in timber surround.
3. Lichen on north slope of roof caused lead in valley below deterioration.
4. Broken slate where hit by falling pot and damage to valley below causing wet rot in gutter timbers.
5. Slipped slates causing water penetration through roof to ceilings area.
6. Water penetration of porous render on gable.
7. Leaves from overhanging tree-blocking gutter caused wet rot in gutter timbers.
8. Blocked off chimney and water penetration, also condensation in flues causing dampness on chimneybreasts below.
9. Valley and hopper head choked with leaves caused wet rot in roof timbers.
10. Water penetration of porous brickwork of gable caused wet rot in ends of purlins.
11. Inadequate rainwater outlet from flat roof caused roof floods and decay in adjacent timbers.
12. Cracked asphalt caused water penetration to timbers beneath and wet rot in bressummers.
13. Cracked sill caused water penetration into wall below and decay in skirting and window board.
14. Plinth bridges damp proof course (d.p.c) caused rising damp.
15. Choked airbricks caused inadequate sub floor ventilation and wet rot in floor timbers.
16. No gulley caused overflow from rainwater pipe soaks under house and decay in adjacent floor timbers.
17. Plinth cracked away caused trapping water.
18. Water penetration of stringcourse caused wet rot in floor timbers.
19. Gutter inadequate to take flow from upper pipe caused dry rot in timbers adjacent to damp wall.
20. Cement fillet cracked away and water seepage causing decay in adjacent timbers.
21. Wet rot in balustrade and foot of posts caused timber decay.
22. Broken gutter caused dry rot in timbers adjacent to damp wall.
23. Wet rot in cellar window frame and lintel from damp wall.
24. Heap of sand caused damp wall and decay in floor timbers.
25. Damp penetration into house walls from porous contacting garden wall.
26. Slab drains towards wall caused decay in sill and floor timbers behind and in lintel below.
27. Rusting stanchions caused bursting of stone slab.
28. Water penetration of porous brickwork caused decay of lintel behind.
29. Render fragments blocking gulley caused rot in floor.
30. Wet rot in door caused by poor quality timber not pre-treated and poor maintenance of paintwork and putty.
31. Overflow from water butt soaking wall caused wet rot in sill.
32. Render broken away caused water penetration of brickwork.
33. Water penetration from high ground level caused damp on basements and floors.
34. Water penetration from overflow caused decay in sill.
35. Flat roof not draining and water seepage causing wet rot in timbers.
36. Flat roof not ventilated and condensation on timbers causing wet rot.
37. Overgrown creeper keeping wall damp.
38. Choked hopper head overflowing caused dry rot in valley timbers and timbers adjacent to damp wall.


Defects in historic buildings according to Fielden (1996:7) occur because “…the building has been subjected to forces and agents not allowed for in the design, qualities of low energy consumption, loose fit and long life of uses”. Basically the majority of defects referring to Eldridge (1976:9-10) are from:
1. The application of forces, either externally or internally, greater than those which the building as a whole, or components or materials of which it is made, can withstand.
2. The effects of materials, whether in a gaseous, liquid or solid state; including those which contribute to the external climatic conditions and those which result from the occupancy of the building.
3. The effect of biological agents and changes in temperature.

These may lead to:
1. Changes in the composition or condition of the materials used in the construction of the building; such changes may then render the materials more susceptible to applied forces, although they were adequate before the changes took place
2. Changes in the construction, ranging from slight cracking not affecting stability to complete destruction.
3. Changes in shape, size or weight
4. Changes in appearance, including colour.

Slight changes from the original condition may not be considered as defects but this depends upon the circumstances. Major changes will usually be considered as defects, but may not if they do not affect the appearance. In general there are four types of changes as follow:
1. Changes in composition result from:
The effects of gases, liquids and gases.
Biological agents.
2. Changes in the structure result from:
Applied physical forces, including those from ground movements.
Climate conditions.
3. Changes in shape, size and weight result from:
Applied physical forces.
Effects of gases, liquids and solids.
Effect of changes of temperature.
4. Changes in appearance result from:
Wear and tear.
Effects of gases, liquids and solids.
Effect of changes of temperature.
Effect of sunlight.

From the more practical aspect, according to Fielden (1996:90) the majority of defects in historic buildings can be caused from one of these main groups as follow:
1. Gravity causes:
Building to fall down.
2. External causes:
Ultraviolet from sun.
Heat radiation.
3. Climatic causes:
Seasonal temperature changes.
Daily temperature changes.
Precipitation of rain and snow.
Ice and frost.
Ground water.
Moisture in soil dust.
4. Biological and botanical causes:
Trees and plants.
Fungi, moulds and lichens.
5. Man made:
Neglect of preventive conservation.
Neglect of fire precautions.
6. Environmental pollution:
Water abstraction.
7. Vandalism and arson:
Neglect f security precautions.
8. Internal causes:
Contaminated air


To understand about the locations, causes and symptoms of defects in detail, it will be easier if it is described based on building elements because there are so many defects that occur in historic buildings with various causes.

3.4.1 Basements

The type of defects that normally occur at basements is damp. Table 3.1 below show the defects and its possible causes.


Ground water under pressure.
Water penetration from construction joints
Damp penetration from subsoil.
Cracked basement walls.
Lack of d.p.c.
By passing of water through d.p.c.
Failure of d.p.c.

Table 3.1 Defects at Basements.

The symptoms of dampness may be observed on walls and on/or floor of the basement or water may be seen to be leaking or seeping through and sometimes may be generally present. The point of entry may be visible as seepage or it may appear as a spout or jet. Care is needed where the basement walls are damp and in contact with timber structure since they may be liable to insect and fungal attack. Older basements may be without any damp proofing. Therefor suspended timber floors in the basements can decay or not owing to inadequacies in the ventilating provision and/or leaking basements. (Hinks & Cook, 1997:174).

3.4.2 External Walls

The type of defects that normally occur at external wall is cracked brickwork, crumbling, powdering and cracking of mortar joints and bricks, movement of brickwork, condensation, efflorescence, damp, extrusion of d.p.c, patchy white deposits, spalling and bowing brickwork, surface disintegration, weathering and surface deterioration and discoloration. Table 3.2 below show the defects and its possible causes.

1.Cracked brickwork either vertical, horizontal, diagonal, coupled, straight, toothed, variable or irregular.
2.Crumbling, powdering and cracking of mortar joints.
3.Crumbling of bricks.
4.Movement of brickwork e.g. balooning, bulging & oversailing.
7.Damp associated with rain.
8.General damp.
9.Extrusion of d.p.c.
10.Patchy white deposits.
11.Spalling brickwork.
12.Bowing brickwork.
13.Surface disintegration.
14.Weathering and surface deterioration.

Subsoil movements.
Foundation movement and failure.
Moisture expansion of brickwork.
Chemical action on brickwork.
Shrinkage or drying out of brickwork.
Thermal movement.
Failure of wall ties.
Spread of the roof structure.
Shrinkage of mortar.
Incorrect mortar mixture.
Corrosion of metal wall ties.
Frost action.
Chemical action.
Sulphate attack.
Leaking gutter or rainwater pipe.
Frost action.
Chemical action.
Moisture expansion.
Chemical action.
Spread or movement of roof structure.
Inadequate ventilation.
Thermal resistance.
Soluble salts in bricks.
Deteriorating brick joints and rendering.
Defective guttering or downpipe.
Excess mortar builds up at various points.
Wall ties put in wrongly.
By passing of water and lack of d.p.c.
Failure of d.p.c material.
Corrosion/frost damage to embedded pipes
Leaching out of lime from plaster.
Slight movements of wall on d.p.c.
Dissolved chemicals by water in bricks.
Frost action.
Initial moisture expansion.
Thermal expansion.
Absence of restrain.
Frost action.
Atmospheric pollution.
Frost action.
Crystallisation of soluble salts.
Splashing of rainwater.

Table 3.2 Defects at External Walls.

The symptoms of horizontal, vertical and diagonal cracks can be seen running along, down or across external walls and may be accompanied by overhanging of brickwork at d.p.c level and/or bowing of the wall. Mortar seems soft and crumbling in the joints, particularly after cold weather and cracks may appear along the horizontal joints. Sometimes brick may absorb moisture shown by damp patches. Some bricks crumble on the surface and are visibly recessed back from the rest. The symptoms of movement of brickwork show either outward bulging of the wall, or where the wall is long, as an oversailing at the end of the wall. Damp can be seen as decorated internal surfaces of wall subject to driving rain are visibly damp shortly after rain. When the wall dries out stains can be seen and there might also be evidence of surface staining or mould growth under the surface. Meanwhile general damp occurs particularly in kitchens and bathrooms. Moisture beads appear on the surface of dense materials and there may be signs of rusted metal fittings and in extreme cases, mould growths. (NBA, 1989:18-36). The symptoms of extrusion of d.p.c are slightly more in evidence than normal, sometimes with beads of bitumen hanging from it. There is often slight outward movement of the wall immediately above the d.p.c and any overlaying mortar may be displaced. Pieces spall off the edges of bricks or brick slips is called spalling brickwork. The spalling may be accompanied by displacement of the brick or brick slips. The symptoms must not be confused with surface disintegration. The symptoms of surface disintegration is either the surface of the bricks crumbles away gradually so that eventually the brick faces become recessed or larger pieces flake off, also leading to recessing of the bricks. The number of bricks affected in any one wall varies considerably where the surface erosion may occur at any time and is more noticeable since the individual flakes may be quite large. The symptoms of weathering and surface deterioration can be seen as the face or edges of the brick/stone are worn or eroded and there is a loss of detail on mouldings and sculptured stones. The face of individual stones may have been split off. There is usually an accumulation of dirt on the surface, often unevenly distributed but it may be thick in places where it is not washed by rain. Lastly the symptoms of discoloration are stained and sometimes covered with efflorescence salts and at other times is damp. The surface of the brick or stonework may be pitted. (Eldridge, 1976:85-152).

3.4.3 Internal Walls and Partitions

The type of defects that normally occur at internal walls and partitions are cracking, damp and patchy white deposits. Table 3.3 below show the defects and its possible causes.

2.Patchy damp.
3.General damp.
4.Patchy white deposits.

Ground movements.
Sulphate attack of foundations.
Deflection of floor slab.
Leaking or overflow pipes.
Leaking pipes embedded in the wall.
Frost damage.
Chemical action.
Leaking waste pipes.
Condensation of water.
Condensation within the thickness of wall.
Interstitial condensation.
Residual water.
Ineffectiveness of d.p.c or flashing.
Splits at the junction.
Cracked, leaking or blocked gutter.
Overflows downpipe.

Table 3.3 Defects at Internal Walls and Partitions.

The symptoms of cracks may be present in any of the internal walls random in direction and varying in width from fine hair cracks to above. Cracks in partition walls, observable in the applied plasterwork, commonly occur when the walls are lightweight bricks. The cracks are often vertical, but may be horizontal, either in the centre of the wall or at its junction with the external wall. They may be found outlining the shape of the walling unit, especially where this happens to be larger than the normal brick size. Meanwhile the dampness appears at internal walls may vary from damp patches to the steady dripping of water. (Eldridge, 1976:133-140). The symptoms of patchy white deposits are efflorescence as it may appear as a white fluffy powdery substance or a hard glassy deposit on internal surfaces. It is often seen on brickwork during the dry period but may occur regularly after prolonged rain. Usually it may be found under paint and wallpaper or on plaster that has not been decorated. Lastly lime bloom is another symptoms of patchy white deposits. It is a white stain on internal surfaces of brickwork at the ends of sills. (NBA, 1989:174-175).

3.4.4 Chimneys

The type of defects that normally occur at chimneys is cracking, splitting and bending and damp. Table 3.4 below show the defects and its possible causes.

1.Cracking, splitting and bending.

Condensation of water vapour.
Sulphate attack.
Defective d.p.c.
Defective chimney pot.
Chemical action.

Table 3.4 Defects at Chimneys.

The symptoms vary appreciably and include cracking of mortar joints, cracking of any applied rendering, vertical splitting of the stack, bending or distortion of the stack, displacement of the chimney pot and damp or stained areas. Brown stains may run down from the soot-cleaning door. There may be damp or stained areas on the plasterwork inside the building immediately below the level of the chimneystack and the roof. Generally, a single damp patch showing on the surface of the chimneybreast serves other type of appliances. The more useful position for the damp patch is on the upper part of the chimneybreast. The patch tends to remain damp irrespective of whether rain has fallen and the decorations may be discoloured. (Eldridge, 1976:187-192).

3.4.5 Ground Floors

The type of defects that normally occur at ground floors is hollowness and curling, lifting and cracking of screed, curling and gaps between boards, lifting or arching of wood blocks and tiles, loss of flooring adhesion and damp. Table 3.5 below show the defects and its possible causes.

1.Hollowness and curling screed.
2.Lifting and cracking of concrete
3.Curling and gaps between boards.
4.Lifting and arching wood blocks
5.Lifting and arching of tiles.
6.Loss of flooring adhesion.

Incorrect mix of screed.
Disturbance of base concrete.
Chemical attack.
Unstable aggregates.
Shrinkage of timber joist.
Damp conditions.
Increase in moisture content.
Irreversible expansion.
Thermal movement.
Shrinkage of the floor screed.
Rising damp.
Changes of moisture content.
Use of unsuitable adhesive.
Inadequate link between d.p.m and d.p.c.
Rising dampness by passing d.p.m.
Leaks from broken appliances.
Leaks from defective joints and pipes.

Table 3.5 Defects at Ground Floors.

The symptoms of defective floor screeds are cracks, splits or unevenness of the floor finishing lying on top of the screed. Where the floor is tiled, the faults may occur along clear lines. The initial indications of lifting and cracking of concrete floors are doors binding on the floor. As the defect worsens, lifting and arching become more pronounced and the surface of the concrete cracks. For timber floors, the symptoms may be seen as the edges of the boards are curled upwards with gaps between the floorboards and cracks along the ridges. Sometimes wood blocks may lift upwards over large areas or along two or three rows only. Sheet flooring may also loss of adhesion where blisters appear in the sheeting and large areas may have come away from the screed and or rippled. For clay floor tiles, it can lift either over a large area or along two or three rows and break away from the bedding. Lastly the symptoms of damp at floor surface can be seen as the tile flooring materials laid on top become quite damp. Carpet laid on an apparently dry floor is covered with mould growths on the underside or in extreme cases has rotted. (NBA, 1989:98-111).

3.4.6 Upper Floors

The type of defects that normally occur at upper floors is collapse of timber floor and joist, timber decay, warping and shrinking floorboard and damp. Table 3.6 below show the defects and its possible causes.

1.Collapse of timber floor and joist.
2.Timber decay.
3.Warping & shrinking floorboard

Fungal attack due to damp condition.
Insect attack.
Wet rot.
Dry rot.
Excessive floor loading.
Ground movement.
Moisture content.
Dry and wet rot.
Deformation of the boards.
Water crossing d.p.c.
Direct water penetration.

Table 3.6 Defects at Upper Floors.

The symptoms of the collapse of the floor may be general or localised. Localised failure occurs more frequently around the perimeter of the floor, especially near the external walls of the building. The floorboards sometimes fail but the main damage may be confined to the joists and supporting wall plates therefor not readily visible. Warping and shrinking floorboards can be seen as gaps appear between timber boards and the edges curl upwards. Covering laid on the boards may become ridged along the board joints and the ridges may crack. (NBA, 1989:92-97). Lastly the symptoms of damp patches are present either on upper floors or ceilings or both. The dampness may be spasmodic in occurrence. (Eldridge, 1976:261-264).

3.4.7 Staircase

The types of defects that normally occur at staircase are timber decay, cracking, loose and collapse parts. Table 3.7 below show the defects and its possible causes.

1.Timber decay.
3.Loose and collapse parts.

Moisture content.
Dry and wet rot.
Moisture content.
Movement in joint.
Defective fixings.

Table 3.7 Defects at Staircase.

The symptoms of timber decay are dry and wet rot. Dry rot is a musty or mouldy smell may be defected and a reddish brown dust and flat mushroom like growths that may appear. Timber with dry rot lack of strengths crumbles easily and is dull brown in colour. Deep cracks divide the wood into brick shaped areas. Meanwhile wet rot usually affects timber that has remained wet for a long time, such as area contact with wet walling. The timber is weak and dark in colour. Any cracking is less deep than that seen in a dry rot attack and there are rarely signs of fungal growths or spores. If visible, the fungus is usually slender, threadlike and dark coloured. (NBA, 1989:180-187). Cracking may due to the seasonal variations in the moisture content of the timber movement in the joint between thread and riser. This can result in cracking of the threads. The fixings between the carriage and the treads may be defective. Treads can wear and may become permanently distorted. The nosing is particularly vulnerable. There may be excessive movement of the handrail. Newel posts can become loose. Stairs to cellars or basements that are damp or have been flooded may be rotten and collapse when used. (Hinks, 1997:133-134).

3.4.8 Flat Roofs

The type of defects that normally occur at flat roofs are splitting and cracking, dents and cuts, edges lifting, surface marking and loss of metal, patina, surface corrosion and pitting, water ingress, blistering, rippling; ponding, general deterioration, loss of chipping, dents and rips and sticky surface. Table 3.8 below show the defects and its possible causes.

1.Spliting and cracking. (Lead).
2.Dents and cuts.
3.Edges lifting.
4.Surface marking/loss of metal.
5.Patina. (Copper).
8.Water ingress.
9.Dents and cuts.
10.Edges lifting.
11.Surface corrosion and pitting. (Zinc).
12.Water ingress.
13.Dents and cuts.
14.Edges lifting.
15.Blistering. (Asphalt).
18.Blistering. (Bitumen).
22.General deterioration.
23.Loss of chipping.
24.Dents and rips.
25.Sticky surface.
26.Water ingress.

Insufficient thickness.
Thermal movement.
Physical damage.
Wind action.
Chemical attack.
Atmospheric pollution.
Chemical incompatibility.
Localised hardening.
Movements of sheeting.
Physical damage.
Wind action.
Atmospheric pollution.
Water draining.
Movements of sheeting.
Physical damage.
Wind action.
Trapped water vaporises.
Condensation of water vapour.
Past of useful life.
Movement of base.
Differential movements.
Expansion of air.
Vaporisation of trapped water.
Condensation of water vapour.
Movement of base.
Past of useful life.
Inadequate falls.
Blockage of drainage.
Inadequate falls.
Wind erosion.
Physical damage.
Chemical damage.
Defective skirting.
Joint failure.
Physical damage.

Table 3.8 Defects at Flat Roofs.

The symptoms of split and crack usually straight, possibly causing leakage of water into the building. Blistering varies in sizes and may be unbroken, in which case affects only the appearance of the roof, but if they are broken they may allow water to pass into the roof structure. Sometimes blistering may be accompanied by a sliding action of the top layer of finishes revealing the edge of the layer underneath it. This may accelerate the rate of leakage. Rippling and cockling may be anywhere on the roof and can vary in size from small to large areas. They may not allow water to leak into the building but splits occurring at the top of a blister may spread so that leakage takes place. Splits, of variable length, may be found at all roofs following a leakage of water through the ceiling below. Most flat roofs are designed to shed the water, which falls on them, but in practice many of them do not shed it completely and areas of the roof remain covered with water until weather conditions allow it to dry off. The ponded areas may be small or quite large. Sometimes they occur around the drainage outlets. Pondage on roofs may lead to leakage, this sometimes being the effect that causes other defects. (Eldridge, 1976:323-337). The moulds and other growths that thrive around the fringes of water ponding areas can drastically reduce the surface reflectance of solar coatings. Stone chippings can trap surface water and increased the incidence of mould growths. Lastly the major failure of the covering is water ingress where the failure is due to the thermal movement caused when the material is exposed to the range of temperatures. (Hinks, 1997:297-316).

3.4.9 Pitched Roofs

The type of defects that normally occur at pitched roofs are timber decay, spreading, sagging, deformation of structure, discoloration and deterioration, slipping and laminated or spalled of tiles or slates, cracking or splitting, loose and rusting of sheeting. Table 3.9 below show the defects and its possible causes.

1.Timber decay.
5.Discoloration and deteriorating tiles or slates.
6.Slipping tiles or slates.
7.Laminated/spalled tiles or slates.
8.Cracking or splitting sheeting.
9.Loose of sheeting.
10.Rusting of sheeting.

Fungal attack.
Insect attack.
Shrinkage of wall plate.
Overloaded or inadequate timbers.
Beetle or fungal attack.
Dry rot.
Fungal attack.
Frost action.
Polluted air.
Fixing no longer holds.
Rusted of nail.
Broken of nail holes.
Weakened of battens.
Frost action.
Polluted air.
Insufficient movements.
Corrosion of fixings.
Thermal and moisture changes.
Subsequent shrinkage.
Corrosion of fixings.
Atmosperic pollution.
Bimetallic corrosion.

Table 3.9 Defects at Pitched Roofs.

The symptoms of timber decay are dry rot and wet rot. Roof spread can be seen as horizontal cracks appear in the external walls near eaves level, more often noticed first on the inside face, with an outward movement of the portion of the wall above. Sagging and deformation of pitched roof can be seen as the roof may sag in severe cases, cracks may be present in the top courses of brickwork immediately under the eaves. These top courses may also have moved outwards or the wall may have moved out of plumb. The tiles or slates have a dished appearance and the ridge may also be bowed. Discoloration can be seen as the tiles or slates become progressively darker in colour and may be almost black. They are weak and porous and leakage through the roof may be the first symptom. Deteriorating and slipping roof tiles may show as signs of surface deterioration. Some tiles may have slopped and if leakage occurs, it may show as damp patches on ceilings. Meanwhile pieces of slate may have broken off and slippage may have occurred. Leakage into the roof space may show by dampness on ceilings. (NBA, 1989:44-49). The symptoms of laminated or spalled roof tiles or slates will show as signs of spalling on top surface or lamination of the body of the tiles or slates. In the course of time more tiles or slates become affected and if they are not replaced rain will leak into the building. Meanwhile for roof sheeting, the cracking may be in one or two forms. Normally the cracks run along the tops of the ridges or profiled sheets or lengthwise down flat sheets intermediately between the fixing points. Individual sheets may also become loose and flap in light winds or are blown completely off the roof. Large areas may become stripped during gales. Rusting may also occur indiscriminately over the steel or metal sheeting or may be confined to the fixing points. (Eldridge, 1976:339-365).

3.4.10 Gutters

The type of defects that normally occur at gutters is leaking. Table 3.10 below show the defects and its possible causes.


Blocked gutters and/or downpipe.
Perforated or joints no longer holds.
Wrongly positioned.
Climatic conditions.

Table 3.10 Defects at Gutters.

The symptoms of leaking gutters are water may leak or overflow from points along the guttering. In some cases, it may cause dampness on external and internal surfaces. (NBA, 1989:50-51).

3.4.11 Rainwater Pipes

The type of defects that normally occur at rainwater pipes are blocked, leaking, perforated and bowing. Tables 3.11 below show the defects and its possible causes.


Blocked by rubbish.
Blocked by plant growth.
Cracked through corrosion.
Displaced through impact.
Bimetallic corrosion.
Thermal expansion.

Table 3.11 Defects at Rainwater Pipes.

The symptoms of blocked and leaking rainwater pipes is water fills the blocked pipe so the gutter eventually overflows. Stains and discoloration may occur on the leaking pipe around joints or on wall behind pipe or gutter. Moss, fungus or even plants may grow from joints or damaged section of pipe. (NBA, 1989:52-53). Sometimes metal downpipes are found to be perforated and leaking. There may be a mass of spongy material in the vicinity of the leaks. If the rainwater is made of plastic, it may be found to be in bowed conditions where the extent of the bowing being greater during hot weather. Initially the bowing will be temporary, but in the course of time it may become permanent. (Eldridge, 1976:366-369).

3.4.12 Windows

The type of defects that normally occur at windows are timber decay, deterioration of paint and putty, distortion of timber and metal frames, staining surrounding, cracking of glass and discoloration. Table 3.12 below show the defects and its possible causes.

1.Timber decay.
2.Deterioration of paint and putty.
3.Distortion of timber.
4.Distortion of metal frames.
5.Staining surrounding.
6.Cracking of glass.
7.Glass discoloration.

Growth of wet rot fungus.
Lack of adhesion due to moisture.
Woodwork not regularly painted.
Uneven application of paint.
Poor fit after shrinkage.
Joints have opened up.
Thermal expansion.
Rusting of steel framework.
Chemical action.

Table 3.12 Defects at Windows.

The symptoms of timber decay are the timber cupped and the underlying areas are soft and friable, sometimes with discoloration of the paintwork. The cupping is more readily visible on broad surfaces such as sills, but can be seen on the narrower transoms and mullions, especially when their width is compared with similar parts that have not become decayed. There may be cross cracking accompanied by darkening of the timber. The lower parts of the frame may have the appearance of being eroded. Deterioration of paintwork and putty is paintwork flaking or peeling off with putties loose, cracked or missing and timber may be soft. Distortion of timber and metal frames is generally too obvious where the joinery is distorted with consequent gaps, lack of fit and draughts. For steel window frames, panes of glass are sometimes found to be cracked or may even be heard to crack. The frames are generally old, show signs of rusting often appreciable in extent, and the putty may be lifted out of its original position. In severe cases the whole frame may be distorted, usually having bowed outwards and might also leave staining at their surroundings. Finally, glass discoloration can be seen when viewed at an oblique angle. (Eldridge, 1976:239-255).

3.4.13 Doors

The type of defects that normally occur at doors are timber decay, deterioration of paint and putty, delamination of plywood panels, distortion of timber and faulty operation. Table 3.13 below show the defects and its possible causes.

1.Timber decay.
2.Deterioration of paint and putty.
3.Delamination of plywood panels.
4.Distortion of timber.
5.Faulty operation.

Wet rot.
Lack of adhesion due to moisture.
Joints have opened up.
Changing of moisture content.
Differences in atmospheric conditions.
Dry conditions and poorly made joints.
Broken or loose of parts.
Swollen or warped door.

Table 3.13 Defects at Doors.

The symptoms of timber decay are flat timber surfaces seem to be deformed and underlying areas are soft and break off easily. Paintwork may be discoloured. The deformation is particularly noticeable if comparison is made between affected and unaffected areas. Deterioration of paintwork and putty is flaking or peeling paintwork with loose, cracked or missing putty and soft timber. External delamination of plywood panels is the outer plywood of the door or panel is wrinkled and becoming detached from the main part of the panel. Where the entire door or panel is plywood, the top plywood may be broken or in severe cases all plywood may have split open at the edges. Paintwork is inevitably in poor condition. Lastly distortion of timber is the door may be warped or swollen so that it no longer fits flush against the door frame, or it may be out of square and catch against the frame or threshold, or both symptoms may be evident resulting a faulty of door operation where doors may stick and not open easily or close properly. (NBA, 1989:64-67).

3.4.14 Timber Structure and Ironworks

The type of defects that normally occur at timber structure and ironworks are dimensional changes, timber decay, deterioration of paint and putty, peeling finishes, dry rot, wet rot, woodworm and metal corrosion. Table 3.14 below show the defects and its possible causes.

1.Dimensional changes.
2.Timber decay.
3.Deterioration of paint and putty.
4.Peeling finishes.
5.Dry rot.
6.Wet rot.
8.Metal corrosion.

Changes in moisture content.
Dry rot and wet rot fungus.
Lack of adhesion due to moisture.
Breakdown of adhesive.
Loss of strength.
Lack of ventilation.
Humid conditions.
Fungi feeding.
Insect attack.
Atmospheric corrosion due to damp.
Chemical corrosion.
Water trapped.
Metallic corrosion.
Stress corrosion.
Metal cracks.

Table 3.14 Defects at Timber Structure and Ironworks.

The symptoms of dimensional changes are gaps or cracks may appear at the joints of components and structure. Gaps may also occur at the junction of timber structure with other building materials. The timber may twist or warp-causing movement of any materials fixed to it. Timber structure, which has been affected by dry rot, is light in weight, loses its strength and crumbles readily, and has a dull brown colour. It can be found to have a split in cubical or brick shaped pieces formed by a combination of deep longitudinal and transerve cracks. The early symptoms of this timber decay may be a characteristic musty, mouldy smell with, later on, the presence of reddish brown dust and the appearance of flat mushroom like growths through joints in the timber. When the timber is opened up a considerable amount of fungal growth may be revealed. Meanwhile timber structure affected by wet rot is usually limited to the ends of joists or rafters, the sides of timber in contact with wet walling materials or timber that has remained wet for an appreciable length of time. The decayed timber is dark in colour and any cracking is less deep than timber affected by dry rot. If the timber structure is painted the cracking will often not be seen, though the timber may have shrunk or become cupped. Sometimes the paintwork is flaking or peeling off followed by putties loose, cracked or missing and the timber may be soft. There are usually few signs of the fungus itself and fruiting bodies are seldom seen in buildings. The affected timber structure is very week. The symptoms of woodworm or insect attack are disfigurement of the surface of timber structure by the appearance of small circular or oval shaped holes and a gradual reduction in strength, sometimes to the point of complete destruction of the sapwood. Where decay is present longhorn beetle commonly known as woodworm may also attack the heartwood. There may be some sawdust like material in the vicinity of the holes. Lastly the symptoms of metal corrosion vary considerably, not only from one metal to another, but even for the same metal. They include expansion of the full thickness of the metal like rusting of steel and the corrosion of aluminium alloys, perforation of the metal ranging from pin holes to large areas, surface pitting, surface discoloration like rust stains, green stains on copper and surface dullness. Corrosion product is usually present, but may not always be correctly identified. (Eldridge, 1976:401-419).

3.4.15 External Wall Finishes

The defects that normally occur at external wall finishes is flaking and cracking of rendering, blistering flaking, peeling, checks, chalking, blooming, wrinkling, balling and colour variability of paintwork, deterioration of varnish, algae, lichen and moses. Mould growths, preferential and pattern staining and dirtying, lime bloom and stains. Table 3.15 below show the defects and its possible causes.

1.Flaking of rendering.
2.Horizontal cracking rendering.
3.Random cracking of rendering.
4.Blistering, flaking, peeling, checks, chalking, blooming, wrinkling, balling and colour variability of paintwork.
5.Deterioration of varnish.
6.Algae, lichen and moses.
7.Mould growths.
8.Preferential dirtying.
9.Preferential and pattern staining.
10.Lime bloom.

Shrinkage of top and bottom coats.
Frost action.
Chemical action.
Sulphate attack.
Cracks of brickwork.
Shrinkage of rendering.
Chemical action.
Climatic conditions.
Chemical or alkali attack.
Shrinkage of paint film.
Entrapped water.
Damp background.
Loss of adhesion.
External atmospheric condition.
Dampness in timber.
Damp conditions.
Supply of mineral salts.
Damp air.
Uneven flow of rainwater.
Air pollution.
Unusual flow of water falling.
Algae growth.
Wet weather.
Polluted atmosphere.

Table 3.15 Defects at External Wall Finishes.

The symptoms of cracking of the rendering with no particular pattern, except that in the later stages there may be a number of horizontal cracks. When tapped the rendering will probably be found to be hollow in places and some areas may have fallen off. The cracks are more prominent than surface crazing of the rendering. Cracks in the rendering are predominantly horizontal. These cracks by distance appear to correspond to the position of the mortar joints in the brickwork. The rendering itself is usually adhering well to the individual bricks. Areas of rendering, sometimes no larger than a single brick break off from the brickwork, generally revealing relatively soft brickwork. The effected areas are in random spots on the wall. The topcoat splits away from the undercoat, sometimes cleanly but sometimes with a thin film of the undercoat adhering to it. The effected areas may vary from small to very extensive. In the early stages, blisters from which when opened may be found to contain water. At later stages the paint film cracks and peels back from the cracks. Efflorescent salts may be present under the paint film. The symptoms of algae, lichens and mosses are coloured vegetable growths on external surfaces especially where there are moist conditions. Meanwhile mould growths are grey, green, black or brown spots or patches, which may spread to form a furry layer on the surfaces of brickwork. It will cause pink or purple discoloration of paint films and the affected areas will generally be damp, or will have been damp. The symptoms of preferential dirtying at external surfaces is dirty in the course of time where the extent depending upon the capacity of the surfaces to retain the dirt that falls on them. Uniform dirtying of a surface may not be obvious, but if the surface is subject to preferential flow of rainwater the dirt will be redistributed so that parts of the surface are clean and others very dirty. Dirty surfaces may weather at a faster rate than the clean surfaces. Preferential staining usually takes the form of long narrow streaks, emanating from features, which are either horizontal or sloping. Theirs’ appearances vary from streak which is cleaner than the remainder of the walling to those which are much dirtier and which may be discoloured green. Trims to roof are common positions for the starts of the streaks. Pattern staining is the upper part of the external wall shows a pattern of the roof construction behind the wall, more usually when this is a pitched roof behind a parapet wall. Lime bloom is a white stain occurring on surfaces close proximity to concrete. It is relatively slow in appearing and does not wash off with water. Lastly stains on external surfaces occurring immediately below copper components and commonly seen on surfaces connected with copper. It is slow in appearing and not removed by washing. (Eldridge, 1976:193-215).

3.4.16 Internal Wall Finishes

The type of defects that normally occur at internal wall finishes are cracking, loose, blowing or pitting plasterwork, discolour and blister decorations, tiles loose or falling off, peeling and flaking paintwork and mould growth, preferential dirtying and pattern staining. Table 3.16 below show the defects and its possible causes.

1.Cracking plasterwork.
2.Loose plasterwork.
3.Blowing or pitting plasterwork.
4.Discolour and blister decoration.
5.Tiles loose or falling off.
6.Peeling and flaking paintwork.
7.Mould growths.
8.Preferential dirtying.
9.Pattern staining.

Initial shrinkage.
Background movements.
Moisture movements.
Thermal movements.
Poor adhesion.
Thermal expansion.
Effects of water absorbing.
Impurities in mixture.
Wetting of surfaces.
Presence of moisture or dampness.
Rain penetration or condensation.
Chemical reaction.
Mould growth.
Unfitted sealing plate.
Shrinkage of background.
Expansion of tiles.
Use of unsuitable adhesive.
Damp and wet conditions.
Poor preparation of previous surface.
Efflorescence under paint film.
Damp surfaces.
Air pollution.
Differences in temperature.

Table 3.16 Defects at Internal Wall Finishes.

The symptoms of crack plasterwork which may be long, but only fine, and which appear at the junction of floors, walls and ceilings, and may also outline the joints of plasterboard sheets or plasterwork. The full thickness of plaster has come away from the background leaving loose areas sound hollow when tapped, and cracks will often be evident. The plaster may bulge or sag, and in extreme cases, will have fallen away. Blowing and pitting of plasterwork is a small conical shaped craters occur in the surface of the plaster generally with a small piece of foreign material in the base. Initially, loose pieces of plaster may be found. Discoloration may be localised or general. It is usually permanent but may be temporary where dampness is present. Some discoloration is distinctly brown, pink, purple or black. It is particularly important when decorations are discoloured around brickwork. Meanwhile blistering is usually localised and occurs on paint films or wallpapers. The blisters are quite often temporary and when broken may create sticky yellowish runs. Some tiles may sound hollow when tapped and may fall off. Paint may also peeling off in large sheets or flaking off in smaller pieces. The symptoms of mould growths are grey, green, black or brown spots or patches are seen on internal decorations, which may have spread to form a furry layer. Paintwork may show signs of pink or purple discoloration. Affected areas are likely to be damp. Lastly preferential dirtying and pattern staining is where the surfaces is sometimes showing distinct areas which are dirtier than others. The pattern may depend on what is behind the surface. (NBA, 1989:80-85).

3.4.17 Ceilings

The type of defects that normally occur at ceilings are cracking and loss of adhesion, shrinking cracks, full thickness of plaster loose, top coat of plaster loose, damp, dirty patches and peeling and flaking finishes. Table 3.17 below show the defects and its possible causes.


One thought on “Historic Building Conservation Dissertation Examples

Leave a Reply

Your email address will not be published. Required fields are marked *