Directory of Traditional Building Skills

DIRECTORY OF TRADITIONAL BUILDING SKILLS

CONTENTS

Introduction
Do's and Don'ts in Maintaining an old Building
Regular Maintenance Checks: a basic List
[Lists of Contractors etc in the Directory are not included on this web page]

Masonry: stone and brick
Roofing: slating, tiling and thatch
Leadwork and copper roofing
Ironmongery and metalwork
Joinery
Plasterwork and renders
Glass and glazing
Tiles and tiling
Painterwork
Fittings
Remedial works
Services
Specialist surveys and photography

Introduction

It is reassuring to realise that despite modern technology, an owner with common sense and respect for the traditional materials and construction methods of a building is its greatest asset. When a building needs more than simple repair, however, it is important to use a professional practitioner to give correct guidance. The Department of the Environment encourages this by offering a high level of grant aid on professional fees incurred during the course of a building contract on many buildings which are listed or within a Conservation Area.

Satisfactory repair requires a craftsman of proven ability. The Directory is based on information recently supplied to the Society by the organisations and individuals concerned and lists people who have experience of working with historic buildings. However, whilst great care has been taken in the compilation of the Directory of Traditional Building Skills, the Ulster Architectural Heritage Society cannot accept any responsibility for the accuracy of its contents, for the consequences of using this information; or for poor workmanship carried out by any of the practitioners or contractors listed here. The Society is unable to give specific recommendations nor does the inclusion of an individual or firm in the Directory imply any form of accreditation by the Society or by the Environment and Heritage Service. The details given under 'Membership' may, in some cases, include organisations which accept members without examination. However, while they cannot always be used as a guide to expertise, such memberships generally indicate a commitment to good standards of practice...

Readers are reminded that Listed Building Consent is required before starting any work on a listed building which may alter its character - this covers any changes to the interior as well as the exterior, and includes replacing windows and doors. Further information about listed buildings can be obtained from Environment and Heritage Service: Built Heritage, 5 - 33 Hill Street, Belfast BT1 2LA, tel. 9023 5000, fax. 9054 3111.

Buildings in Conservation Areas are also protected, and advice should always be sought from the local Divisional Planning Office before starting work.

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Maintaining an Old Building:

Old buildings are more than bricks, stone, mud and mortar. In them we have material evidence of the past and a visual asset for the present and future. Inappropriate alteration or repair can cause great damage to the character and interest of these structures. Current legislation should prevent demolition and more extreme forms of alteration to the exteriors and interiors of listed buildings; but often minor works to listed buildings and major changes to unlisted historic structures are left to the owner's discretion. In such cases an appreciation of the building and its construction and the use of appropriate repair techniques will be of particular importance. Professionals with the traditional skills needed to retain the character of old buildings should then be consulted.

Most people now accept that it is important to protect those great houses and national monuments which provide reference points - either good or bad - in history. About the need to conserve more 'ordinary' old buildings there is greater doubt. Often it is felt that these structures have nothing exceptional to contribute in architectural or historic terms and that their retention is unnecessary and prevents progress. But more humble historic buildings do have something to contribute, both on an individual basis and in a wider context. Frequently it is the simpler vernacular structures that form the architectural character of an area. Their materials, for instance, are likely to relate directly to the locality in which they were built in a way that modern structures made from mass produced materials often do not. Their form may well indicate their previous use and through this the past commercial or social role of the area in which they stand. Individually, although perhaps unremarkable, they are likely to contain evidence of design and craftsmanship generally not found in modern, mechanised construction. For instance the proportions of a classical facade, the undulations in old plaster and glass or the variations in colour and texture of hand-thrown bricks and tiles are all worthy of appreciation.

To look after an old building in a careful and sensitive manner requires some knowledge of its history and constructional form. It also involves regular maintenance and the ability to distinguish ageing, which is gradual and pleasing, from growing problems. This may sound complicated but, with some good basic information combined with common sense, an appropriate approach should be possible.

There are some significant differences between traditional and modern forms of construction which should be appreciated as the basis for understanding an old building. A full explanation of this subject is not possible here - information such as the Society for the Protection of Ancient Buildings pamphlet The need for old buildings to 'breathe' can help with this - but some of the fundamental differences include solid rather than cavity wall construction, the absence of modern forms of damp proof courses and membranes, and the use of 'breathing' rather than impervious materials. In essence old buildings normally have a 'softer' form of construction which allows a greater amount of structural movement and migration of moisture. This may sound alarming, but problems are only likely to arise if maintenance is inadequate, if incompatible modern materials are introduced (such as hard cement mortars, plasters and renders which hinder the evaporation of moisture unlike traditional lime-based mortars which allow it to take place) or if structural alterations are made which interfere with the way in which a building was intended to perform.

Roofs, Chimneys and Rainwater Disposal:
Ensuring effective rainwater disposal is a crucial part of good maintenance. Water should be rapidly channelled away from roofs or other surfaces so that there is no risk of unwanted moisture penetrating the structure. It is also essential that there is a satisfactory means of taking water away from the base of the building so that it does not affect foundations or cause decay through excessive 'splash back' onto the walls.

Roof coverings are often attractive as well as functional elements of a building. Wherever possible traditional materials should be used for re-covering roofs. This should apply not only to slates and tiles, where natural/handmade types are greatly preferable, but also to thatch which should be appropriate to the locality in terms of material and detail. Slipped slates and tiles, copings to gable ends and the gradual decay of thatch should all be watched and remedial action taken when necessary.

The condition of gutters and downpipes should be regularly monitored; occasional inspections during heavy rain showers can be a revealing way of seeing how the rainwater goods cope with water from the roof. At other times stained masonry is likely to indicate that there is a defect of some kind such as a blockage or crack. At regular intervals - ideally in the Spring and Autumn - leaves and other obstructions should be cleared.. Heavy snow can also cause blockages and flooding as it melts - if this is of particular concern snow boards or other modern alternatives can be used to guard against potential blockages. Also to be considered is the condition of lead flashings to chimneys and junctions and other leadwork, such as to valley or parapet gutters and to door canopies or bay windows. Leadwork will not last indefinitely and ultimately will need to be repaired or replaced. The involvement of a specialist is then advisable.

Masonry:
The masonry of a building is not merely the structural material between the building's architectural features; the type of material used and its treatment are essential parts of the building's character. Traditionally there was, in general, an intention to create a unity in the surface of the wall rather than to emphasise the presence of bricks or stones in the construction. Thus modern 'ribbon' pointing, which creates mortar joints raised from the surface of the masonry, is almost always inappropriate for an old building. Rubble stonework was very often unified by a coating of render and/or limewash. Where used, traditional specialist techniques, such as tuck pointing where the irregularities of the bricks are first disguised by a mortar that matches their colour, and then this mortar is scored with a narrow line which is itself pointed to produce the appearance of a neat and slim joint - should be respected as an essential part of the character of the brick wall.

Regular checks should be made on the condition of the masonry and mortar joints. The mortar, traditionally lime-based in most cases, should be softer than the surrounding masonry. As such it is intended to be a 'sacrificial' element of the building where erosion will occur. It is usually felt that re-pointing is required when the depth of recession exceeds the width of the joint. The growth of vegetation near to and within the masonry also needs to be controlled as damage may result.

Any significant structural problems with masonry are likely to require professional involvement but the owner should watch for evidence of on-going movement such as the widening of joints. However, cracks and distortions are not necessarily a problem; in some cases they will have occurred early in the building's history and will not be a continuing cause for concern.

Windows and Doors:
The detail of traditional joinery is most important to the character of an old building. 'Off the peg' modern replacement doors and windows can bear a superficial resemblance to earlier examples but generally they lack the interest of the original in terms of form and detail. Particularly unsuitable are modern units in PVC-U, aluminium or tropical hardwood. Even if they make an attempt at a traditional design they are almost invariably a very poor substitute; typical unsatisfactory details include glazing bars stuck onto plate glass, fanlights incorporated into doors, over-reflective double glazing and imitation sash windows where sashes pivot rather than slide.

Contrary to some manufacturers' claims, there is also evidence that PVC-U does not have a great life expectancy. Timber windows and doors, if properly maintained, can last almost indefinitely.
Similarly old glass, including crown or cylinder types, differs significantly from modern forms. Old glass should be valued for its colour and texture; these factors can make a surprisingly important contribution to the character of windows. Retention of old glass avoids the mechanical, lifeless look that can occur with modern replacement fenestration.

Regular maintenance of traditional windows and doors should include repainting, lubricating hinges and other sliding parts and checking putty to glazing for cracks. If required, draught proofing, or secondary glazing can be installed without harming the fabric of an old window or door.

Interiors:
Interiors of traditional character should be appreciated. Modern replacement fittings such as doors, skirting boards, fitted cupboards and door furniture are likely to date quickly and lose their attraction whereas a well maintained traditional interior will retain its interest and is likely to become increasingly important to the value of the building. In most cases there should not be any major conflict between modern living and the retention of historic features.

Evidence of internal decay such as damp patches, deteriorating plaster and fungal attack to timber may indicate problems connected with the building's basic fabric and disposal of rainwater; but poor ventilation combined with the evaporation of water from baths and kettles may be responsible for some of these problems. In all such cases it is necessary to find the problem and resolve it before further difficulties arise.

A basic understanding of the form of construction, careful and regular maintenance and the use of appropriate traditional skills and materials are of fundamental importance to the care of historic buildings. With this the building is unlikely to cause problems, and the varied qualities that contribute to its historic character, whether grand or humble, can be fully appreciated.

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Regular Maintenance Checks:

Exterior:

Roofs - check for slipped, cracked or missing slates and ridge tiles, decayed flashings and dislodged chimney pots and copings.
Rainwater disposal - check for holes in, and misalignment of, gutters and downpipes; and evidence of blockages, including drains.
Walls - watch for new bulging or cracking of masonry; deterioration of brick or stone surfaces; cracking or detachment of render; excessive erosion of mortar joints; and control the spread of plant growth into, or at the base of walls.
Joinery and paintwork - check for flaking paint and cracking timber to doors, windows, bargeboards etc.
Windows - look for damage to panes, and for cracked putty.

Interior:

Roofspace - look for evidence of water penetration.
Walls and ceilings - check plaster for damp or deteriorating patches and for the efflorescence of salts. These may indicate damp problems, requiring investigation.
Timbers and joinery - look for evidence of fungal growth on, or connected with timber. A mouldy smell may indicate decay, as in some circumstances may springy timber floors . As fungal attack is most likely in dark, poorly ventilated areas, check cupboards and under stair areas, etc. Also, look for evidence of new beetle attack such as frass: adult beetles usually emerge from timber between May and August.
Pipework - check water and heating pipes (particularly in areas not normally seen) for evidence of leaking joints.

This section was written by Matthew Slocombe of the Society for the Protection of Ancient Buildings

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Masonry: Stone and Brick:

Dressed, or finely cut, stonework is comparatively rare in Ireland, it was mainly used on grand buses, churches and public buildings. Many buildings are in rubble stone, often limewashed or rendered; however for the last hundred years brick has been the predominant material.

Unfortunately through time some of the skills and appreciation of the demands in working with stone have been lost. In the recent past it was difficult to get the right advice, the right materials and the craftsmen to work sympathetically on stone. Now the climate has changed, there is a revival of interest and it is possible now to have good work carried out - there are no longer any excuses for botched repairs and alterations.

Stone buildings weather, often attractively, but pollutants can disfigure and decay. There is a long and inglorious history of attempts to slow down and stop this weathering process; many techniques have caused more damage than if the building was left alone.

Stone walls need to breathe and need to remain flexible. Lime should be the basis for mortars, grouts, washes and renders. Some superior work made use of hydraulic lime which has a degree of natural 'set' akin to cement, but most construction work made use of pure, non-hydraulic lime in the form of lime putty mixed with aggregate. This material can only harden when in contact with air and in some circumstances may take many years to set completely. The great advantage, however, is that unlike cement and the stronger hydraulic limes, pure lime putty is porous, thereby allowing moisture entering the fabric of the building to evaporate and escape. It is also flexible so accommodating minor structural movement without cracking. Lime putty is now readily available from suppliers in Northern Ireland and the Republic of Ireland.

Cement render is not a suitable material for use on a historic building and is not a cure for damp problems. A thick porous lime plaster coating will give the best weatherproofing and durability results on solid masonry walls.

Cleaning, if necessary at all, is an expert's job, a complex process that requires a sensitive touch and deep understanding. High pressure grit blasting and indiscriminate use of powerful chemicals have caused enormous damage and must be avoided. Newer, gentler methods have been developed and are already in use. Above all, a full survey of the building needs to be carried out before any decisions are made, samples taken and tests done to determine appropriate repair, replacement and cleaning methods. Then a very detailed specification should be drawn up to ensure that the work is carried out correctly; good site supervision is essential.
Stone walls are usually thick, 400-600mm is common, and inherently stable though the enlargement of openings or breaking out new ones can be hazardous and should only be carried out with professional advice. Walls do move, bend, twist and lean and in modest buildings may have little or no foundations. Such problems do not usually require panic measures but an acceptance that old structures will not necessarily be square, plumb or true. Lime mortars and renders remain flexible and can accommodate such movements. Attempts to straighten walls will both remove the character and prove enormously expensive. External French drains, damp proof membranes in floors and electro-osmotic damp proof courses can alleviate damp penetration and, in most cases, original walls can be retained.

Whilst building or repairing rubble stone walls is within the capability of good bricklayers and local masons, provided they observe and follow the pattern of the original and do not invent their own vertical crazy paving, ashlar and dressed stone is a specialist task. There are firms of experienced stone masons working in Northern Ireland who can repair and replicate fine stonework, and although much of the new stone currently used in decorative work is imported many types of building stone are available from quarries in the British Isles. Statuary and sculpture require the most skilled of all conservators.

Brick buildings abound in the urban areas of Ireland although there are few of the classic Georgian terraces left in Belfast, or indeed Ulster, to match those of Dublin. Bricks were made in local brickyards and often the names, such as Hampton, Laganvale or Annadale, were stamped into the clay. Most local bricks are bright red, a product of the local clays, but a burnt purply red which has weathered to a very deep shade, is common. They are almost impossible to reproduce in new brick but can be obtained on the salvaged brick market. Many old bricks were to an 'imperial' size, deeper than the modern metric brick and of a different, more solid character when built. Some brick companies still manufacture a limited range in 'imperial' sizes. Seventeenth and eighteenth century bricks were often quite irregular and did not follow standard sizes at all.

Traditional brick walls were solid, 9" or greater, with a variety of bonds which give both strength and character. Most modern walls are of cavity construction which inevitably means a simple stretcher bond. Extensions to old buildings should respect the original bond types, either by using 'snapped' headers or a solid wall construction with the damp kept at bay by the 'breathability' of the wall and insulation taken care of on the inner face.

Old bricks are invariably uneven. Lime mortar, as with stone, allows for flexibility and ensures that the shrinkage cracks, associated with modern hard cements, will not occur.

The classic yellow stock bricks, often used in chimneys and quoins, and the blue engineering bricks, found in plinths, were mostly imported from areas with those colours of clays and are usually very dense and of high quality. Salvaged bricks should again be the first choice but good reproductions can be obtained.

The pointing of stone and brickwork is critical to its character. A lime based mortar should be used, not hard cement, for the general principle of pointing is that the joints should be weaker than the brick or stone. Raised or strap pointing is nearly always wrong. Instead joints should be raked back to a depth of at least twice the height of the joint and the new mortar brought forward until nearly flush with the edges of the stone or brick, not covering them or smeared over the surface, and struck slightly (splayed from the top down) to throw the water off. Any mortar used in historic work should be in the range 1:3 lime putty to sand up to 1:2:9 cement to lime putty to sand. The joints can then be rubbed down with a hessian bag or a soft bristle brush when nearly dry to expose the aggregate which should be chosen to match the original in colour and texture. In rubble stone work with wide joints 'snecking', small stones set within the mortar is often found.

In ashlar work, with very tight joints, special techniques and grouts are required to pack the mortar into the joints and keep the surface clean.

Rubble stonework was rarely built to be seen and the current fashion for stripping off the render can lead to rainwater penetration as well as aesthetically being unattractive.

Research into the most appropriate ways of using lime as a material for repairing historic buildings and monuments is ongoing. Please contact the UAHS for additional information on this subject

Stonework Repairs:
This is a complex subject which requires expert guidance. The choice of techniques available is outlined below in a simplified form.

The first step in any repair scheme is to evaluate the existing state of the stonework and the degree off intervention and repair necessary. This evaluation has implications for the types of repair techniques to be undertaken and their application as exhibited by different stones or elements of the building. When various methods of repair are matched to particular stone problems, sometimes in one building or even a single façade, this is referred to as a 'palette of techniques'. The overriding principle is to retain as much as possible of the original stone.

Repair Techniques
(a) Complete stone replacement:
This an extreme measure, rarely necessary and very expensive, involving the complete rebuilding of a façade or building. It is often difficult to obtain original or compatible stone and this solution should only be used when there is complete failure of the stone or metal fixings.

b) Replacement of individual stones:
Weathering of stone is endlessly variable and individual stones may fail for many reasons - surface spalling, fixing failure, structural movement etc. Geological matching is critical to ensure compatibility of future weathering. Stones can be replaced either to full depth or, more commonly, to 75-lOOmm thickness, depending on the amount of decay of the original stone. Fixings may be necessary and should be of stainless steel to avoid corrosion.

c) Indenting:
Where only a small section of an original stone is damaged - e.g. by rusting around a railing fixing - it is more appropriate to replace only a small section of stone. The new stone needs to be geologically matched, as noted above, to a similar 75-100mm depth, and should be tightly butted to the original, without expressing the joint, and fixed as necessary. In finer work much smaller indents are possible, often held in place with epoxy grouts

d) Render repairs:
Large scale render or 'plastic' repairs are now largely discredited though this is a useful technique for small scale repairs to complicated carvings or sculpture. The renders must be of a 'soft' lime based mix to avoid accelerated weathering of surrounding stone. Stainless steel wire cages can be used to build up profiles. This is a technique for expert conservators, not a cheap alternative to correct stone repairs.

e) Consolidants:
Chemical consolidants can delay weathering of stone and help delay or avoid replacement. However, the associated chemistry and geology is complex and specialist scientific and laboratory assistance is required with full testing before application.

f) Redressing:
When surface failure has occurred a technique sometimes considered is the redressing of the stonework to its original profile. This is a skilled stonemasons' task. It is possible to reface chemically consolidated stonework as discussed under item (e), particularly rock faced walling that shows facial deterioration. Generally only 15-25mm of the decayed stone is removed to allow realignment to the original profile. This technique is used for decayed stone deeply embedded within a wall which itself has minimal decay yet is disfigured. Door cases and window cills are particular examples on which this technique can be used.

See also
Leadwork (for flashings etc.)
Metalwork (for metal cramps and fixings)
Plasterwork (for external renders)
Remedial Works (for DPCs and other treatments)

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Roofing: Slating, Tiling and Thatch:

Thatch is the traditional roofing material of Ireland and was almost universal in modest houses until the mid nineteenth century. Locally available split stone or slate was used but it was not until the widespread availability of cheap Welsh slate that the major changes occurred. Slate required little maintenance, was easily worked, attractive, and remained the main roofing material until very recent times. Widespread use of clay and concrete tiles has surpassed the use of slate but it remains the best material for repairs and extensions to old buildings.

Thatch has declined alarmingly - there are now fewer than 200 inhabited thatched buildings in Northern Ireland. Concern is so great for their survival outside museums that the Environment and Heritage Service are offering 75% grants towards thatching and maintenance. Old problems of damp and mould are easily solved today and while regular maintenance is required the benefits of beauty and character plus the grant available can swing the financial balance. There has been a great revival of interest in thatching in Britain and this is spreading to Northern Ireland. Thatchers are now more easily found and there is no doubt that the craft will develop with the revival of interest in thatching.

Natural slate is also enjoying a revival and with the high cost of new slate a market-led demand for salvaged slate has emerged. When re-roofing is necessary careful choice is required to avoid a patchwork quilt of blues and greys as there are considerable differences in colour. It is wise to avoid mixing slates from different sources so the original ones should be kept together and used on the most prominent elevations. Delaminated slates or ones with splits or overlarge nail holes should be discarded. Variations in detail in the roofscape such as rows of particularly large slates at the eaves, called queens, diminishing courses, that is slates getting gradually smaller towards the ridge, and the ridge materials (stone, clay or lead) are of immense importance to the character of the building and should be retained. It is vital to check roofs regularly for slipped or missing slates and to repair promptly.

Westmoreland or Norwegian green slates were popular in Ireland in the inter-war years and it is still possible to get new slates to match. Clay tiles are a very old roofing material rarely found in Northern Ireland until modern times when the 'Rosemary' small plain tile became popular. Cedar shingles enjoyed a brief boom in the 1950s but in general have not fared well in the damp climate.

In general natural slate roofs should have a minimum of 35° pitch, rising to 45° or greater for small slates. Where it is not possible to lay natural slate, a different material such as lead should be used.

Finally, painted corrugated metal sheeting is a traditional roof in the country, mainly over barns and out-buildings, but often over the top of thatch on houses. Black, green or red lead are the common colours and their use should be considered on all rural building groups.

See also
Leadwork (for flashings)
Remedial works (for chimneys)

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Leadwork and Copper Roofing:

Leadwork is still often carried out by a plumber, recalling the origin of the trade. Lead is an extremely durable and flexible material but it does demand expertise. Good detailing and practice are essential to ensure excessive thermal movement does not open joints, sag flashings or stretch large flat sheets so that they split open.

Old buildings sometime have complex roof structures with hidden gutters and valleys. Leaks are sources of problems which may be out of sight, while slow leaks saturate roof timbers and may lead to dry rot.

Valleys and valley gutters should be broad, laid to good falls and easily cleaned. Overflows should be positioned in prominent locations to warn of gutter blockages; regular maintenance is essential. In important buildings moisture sensitive alarms can be installed underneath hidden valleys to warn of damp penetration. Flashings on chimneys, parapets, abutments etc. all require well detailed lead of appropriate thickness, size and design.

The Lead Sheet Association publishes details of good practice, carries out research and offers an advice service. The Lead Contractors Association publishes a directory of specialist leadworking contractors and has four members in Northern Ireland.

These publications can be obtained from:

The Lead Contractors Association and the Lead Sheet Association
St John's Road
Tunbridge Wells
Kent TN4 9XA
Tel: 01892 513737
Fax: 01892 535028

Copper roofing is the traditional material for domes and cupolas, and correct installation is a skilled trade. It is a versatile and very attractive material, and can now be supplied in prepatinated form to avoid the problems associated with unsightly weathering in the early years.

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Ironmongery and Metalwork:

Early door and window furniture originated with the local craftsmen, blacksmiths and metal workers, and so are often unique to an area. Factory made ironmongery gradually evolved until the Victorian era when a complex variety of door and window fittings were mass produced. Many of these are again available as some firms specialise in exact reproductions of the original.

Old door furniture can be restored and if the locks fail to match modern security requirements a discreetly placed deadlock can supplement them without interfering with the character. Replacement ironmongery and fittings must be chosen carefully to match the period of the building.

In most traditional buildings gutters and downpipes are of cast iron, usually with either a half round or ogee faced box section. Although long lasting, cast iron eventually rusts away at the joints and owners often find that their gutters leak and are difficult to repair. Replacement in PVC or extruded aluminium is not the answer for old buildings though some cast aluminium systems do match the details correctly and eliminate the maintenance problems of cast iron. On historic buildings there is no substitute for replacement in new cast iron which is available with all the fittings, brackets and hoppers to match the original. One common problem is when guttering in one terrace house needs to be replaced for it is difficult to patch an existing gutter. Some firms specialise in glass fibre based junction pieces for those awkward areas and this can avoid the replacement of guttering that is otherwise adequate.

Stonework often has hidden metal fixings, cramps and ties and these are invariably of iron rather than the more stable bronze. Damp penetration over the years rusts these fixings and they expand which causes the stone to crack and explode. Extensive replacement with stainless steel fixings may be necessary in serious cases but good maintenance of pointing and flashings can prevent serious problems occurring.

Restoration of industrial machinery is becoming more widespread and with it the recognition of the specialist repair and maintenance skills involved. It requires a unique blend of artistry and craft to manufacture replacement parts from the most basic of materials and to reassemble long disused machinery into working order. It is important to ensure that this machinery works thereby keeping the skills alive.

Metal balustrades, balconies, gates, railings, windows, rooflights, light brackets and a host of other fittings can be repaired or reproduced. Specialist companies produce exact copies from Victorian catalogues and skilled metal workers can repair or recast broken or missing pieces.

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Joinery:

Of all building elements windows, doors, their fittings and embellishments can usually tell more of the history of a building than any other. Unfortunately many Georgian terraces, Victorian houses and Edwardian villas have had their picture rails, deeply moulded skirtings and architraves removed, but fashions change and many people now want to restore some of the character of their buildings.

Wood is still the most versatile construction material known and for interior fittings is unsurpassed. Good joiners can make anything from a drawing, a scrap of the original or even a photograph. There are ranges of standard mouldings, in many cases these will be appropriate, but local and regional variation is important and particular mouldings may be specially cut. It is usually not much more expensive to do this particularly when long runs are involved. The scale and proportion of the room should determine the complexity of the mouldings, otherwise the joinery becomes grander than the building. For replication purposes examples may be found from other houses of the same period which have not been altered or from museums or photographs. Sometimes details on the outside of the building were replicated inside. Often mouldings were covered up rather than torn out and may be found tucked away under the stairs or in the attic.

Windows deserve a special mention as they are probably the most important factor in the appearance of a building. Timber sliding sash windows, the glazing often divided into small rectangular panes, are the most common traditional window type in Ireland. They look marvellous and give efficient ventilation control and ease of escape in the case of a fire.
However, they have a reputation for being draughty and hard to maintain. These problems are exaggerated by salesmen of PVC-U replacements who claim their reproductions look the same and as a result, a rash of replacement windows is sweeping the country. Sometimes thin strips are inserted between two panes of a double glazed unit in an attempt to replicate the pattern of glazing bars, but they fail miserably, fool nobody, are awkward and clumsy, an insult to an old house and stomach turning pastiche in a new one. In addition, there is growing concern over the environmental implications of the use of PVC-U and the toxic waste it can give off in fires.
It is always preferable, and often cheaper, to repair rather than to replace original windows; exact replacements of fine glazing bars and mouldings can be made. Details like the width of frame showing around the window on the outside are of historical importance and should be faithfully matched. Traditional sash windows can be fully draught proofed, easily and inexpensively, with a comprehensive system of brushes and seals. Fitting 'Simplex' sash hinges allow the windows to be cleaned from the inside. In the event of decay, hardwood sections painted to match the original, can be inserted as in many cases it is only small areas of the sash, usually the cill member, that have decayed.

Weights, sash cords and pulley wheels can be overhauled and replacements are also available Some very small windows never had weights, instead a piece of wood jammed the sash open. Modern spiral balances are an appropriate replacement in some circumstances, but in listed buildings the original system should be replicated.

Leaded windows have also been in use since very early times. In the late eighteenth century some of the simpler forms of leaded windows were copied in cast iron but these forms are rare in comparison to the vertically sliding sash windows.

It is difficult to insert double glazing on small paned sash windows without increasing the size of the glazing bars. Double glazing is the least economic way of insulating a building; it is better to draught seal the windows. Shutters or heavy curtains may be used, radiators placed under windows and an extra layer of insulation added to the roof. Secondary glazing can also be effective and does not destroy the character of a building.

There is an endless variety of traditional door types, both sheeted, and framed and sheeted, or panelled, generally with four or six panels. Some modern 'off the peg' doors are good but others are inappropriate reproductions and have no place in old buildings. Traditional door sizes rarely match 'off the peg' doors and the opening itself should not be changed - the original widths and heights are more important than modern standardisation. Many panelled doors were unnecessarily ripped out, or sheeted over, to improve fire resistance. It is perfectly feasible to upgrade an existing door without losing its character; however the Fire Authority often require test certificates, mainly in public buildings, so new fire resisting panelled doors may have to be made in some instances. Architraves and jamb wall panelling that frame the door should be retained or replicated.

Doors were invariably painted, though they were sometimes grained and the modern preoccupation with natural pine, though attractive, is historically incorrect. External doors, except in the rare cases where they were made from oak, walnut, teak or other exotic woods, must be painted.

External joinery, especially fascias and barge boards, require maintenance and should be made to a high specification if replication becomes necessary. Treated softwood, exterior plywood, hardwood and exterior timber particle boards are all useful and should be painted. Decorative timber barge boards, generally Victorian, are very important features to a building and should be retained.

Finally, the conservation of historic buildings should not be at the expense of the world's forests; all timber used should be specified as coming from a sustainable source. There are difficulties in verifying such claims at present but it is expected that, in the near future, a reliable identification system will be established.

See also
Glass and Glazing

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Plasterwork and Renders:

Until the 1930s lime based plasters were standard and so most old buildings are plastered internally with three coat lime plaster, either directly onto the brick or stone (on the hard) or on horizontal laths on timber framing or joists. The backing coats were generally reinforced with hair or vegetable fibres (fibrous plaster) especially the fine, run (made in situ) cornices which were common even in modest buildings. Decorative plasterwork of the eighteenth and nineteenth century can be quite stunning.

Excessive movement in weakening ceiling joists causes cracks, and damp penetration can crumble the surface. Both problems cause the plaster to detach from the laths and eventually fall off. Lath and plaster ceilings and walls are difficult to patch and much fine plasterwork has been lost through lack of timely maintenance. Rot in supporting timbers has long been the excuse for wholesale stripping out of plaster but non-destructive methods are possible combined with the removal of the source of the problem and the insertion, where necessary, of ventilating voids. At the very least cornices and ceiling roses can be securely fixed and repaired in situ.

Cornices, roses and other features are all available as pre-formed mouldings and good plasterers can make up and repair run mouldings. Most fibrous plaster companies can replicate the patterns of cornices and ceiling roses from damaged work or make models from contemporary properties.

For repairs to ordinary, as well as more important historic buildings, plaster made from lime putty and fine sand should be used. In certain circumstances, for example where a wall is very damp, it may, however, be expedient to use a bagged, lime based plaster, such as Limelite from Tilcon which retains some degree of 'breathability' and flexibility after setting.

External renders vary from simple work lined out to resemble stonework, to elaborate stucco pilaster cornices and mouldings. Early examples are in lime based render but by the mid nineteenth century 'Roman Cement', a naturally occurring clay and lime mix, was the most common material; it is not available today.

Renders are subject to thermal stresses and movements in the building fabric. In order to accommodate such movement without cracking and to allow water which is drawn into the fabric to evaporate off, renders, like plasters, should always be lime based. The addition of cement as a gauging material, although common place, is not generally regarded as good conservation practice. In any event, the proportion of cement to lime should not exceed 1:2. If the mix is too cement strong, it will crack, let in water which is unable to escape and eventually detach from the wall.

Many renders contain a stone aggregate. Dry dash, or pebble dash, where the stones are flung on to the wet base coat, is an inappropriate finish for any historic building. A traditional wet dash, where the aggregate is mixed into the render before it is applied to the wall is more suitable. The exact size and type of stone and the texture and colour of the sand used is critical and should be matched to the original work where possible.

Traditional smooth rendered walls, sometimes with 'ashlar' lines marking the 'courses' to resemble stone, were intended to be painted, unless it was already self-coloured by the addition of coloured sands in the render mix.

The successful use of renders and plasters made from lime putty without the addition of cement requires particular skills, both in their specification and their application and after-care on site. Please contact the UAHS for further advice on this subject.

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Glass and Glazing:

Window design developed with technical advances in the production of glass. Early blown glass was replaced by spun glass in the eighteenth century and is still to be found in many historic buildings. It is characterised by irregularities, bubbles and defects. Modern sheet or plate glass, developed by the nineteenth century, is largely free from such defects and so is no match for historic glass. Spun glass is becomingly increasingly valuable and period glass is now available; for vernacular buildings agricultural glass may be used.

Nineteenth century float glass allowed larger and more regular panes and simplified glazing patterns. Inexpensive stained glass became available with a range of etched and patterned glasses and was widely used in hall doors, stairs and landings. Stained glass repair is best left to specialist craftsmen. The lead that separates the glass is prone to distortion, sagging and expansion buckling, especially in the larger frames. Sometimes the only solution is complete re-leading although it may be possible to sandwich an old, fragile window between sheets of plain glass. Conservators retain stocks of old glass for repairs.

Modern safety regulations can demand that toughened or laminated glass is used in doors or low windows where a change of use or major renovations require Building Control Approval. This may be too thick for the old mouldings and its greenish colour changes the character. Secondary glazing or internal balustrades may be alternative solutions which preserve the character of the original.

Historically, glass was invariably putty glazed and modern timber slips are inappropriate. For sound insulation internal, secondary glazing is most effective and although inappropriate for fine interiors it does retain the integrity of the original windows.

See also
Joinery

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Tiles and Tiling:

Although pounded earth floors were still common in rural vernacular houses until recent times, it is more usual to find slabs of stone, slate, marble and clay 'quarry' tiles laid on ground floors in halls, kitchens and sculleries, with boarded timber floors on joists in the more 'important' rooms and on the upper floors. Original tiled floors add great character to a building, but because they are often laid directly onto the earth, they can be damp and cold. The comfort level can be transformed and the appearance retained by lifting the tiles and re-laying them over a damp proof membrane and rigid insulation on a concrete screed. New and salvaged slate and quarry tiles are available. Laying old tiles may be more costly than putting down modern materials because, like many natural products they may be irregular in shape and thickness but the quality and look of the finished floor should repay this extra effort.

Quarry tiles, which are unglazed, need to be sealed after laying and cleaning to prevent them absorbing stains. The traditional method was to use linseed oil and wax polish. This will make the floor shine but is very labour intensive and a modern cold wax polish is a suitable alternative. Tiled floors should never be treated with any kind of polyurethane coating. This gives a completely inauthentic appearance and may cause the tiles to 'sweat' making for long-term problems by trapping moisture beneath the floor.

The Victorians were fond of small clay floor tiles, commonly laid in complex mosaic patterns, for front halls, hearths, garden paths and churches. They are durable and easy to maintain and should be retained wherever possible. Such geometric tiles are still being made.

Wall tiles have a long history but Victorian mass production, especially for fireplaces ensured widespread popularity. An enormous variety of mouldings and designs created interiors of some opulence in both private and commercial buildings. Wonderful Art Nouveau tiles with stylised plants became common in domestic interiors and new precise reproductions are available.

0ld tiles are often very firmly fixed and can easily be broken, so great care is needed when stripping an area for re-use. Rather than replace a large area of original tiles, it may be preferable to repair any broken or damaged ones in situ, clean them thoroughly but gently and re-grout.

External tiles made of terracotta or 'faience' were frequently used during the late nineteenth and early twentieth centuries. This material is fragile and easily damaged by clumsy cleaning or repairs and specialist advice should be sought before starting work.

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Painterwork:

Paint has long been used for the decoration and protection of timber, metal and plaster coatings, and the correct specification is a complex task. Painted surfaces on old buildings will have been built up in many layers and careful stripping back of a small sample area will give clues to a building's decorative history. Caution must be taken when rubbing down old paintwork to avoid inhalation of toxic dust, particularly on timber, because of the former use of lead-based paints. Currently the use of lead paint is restricted by stringent Health and Safety regulations.

Putting together a new, historically correct painting scheme is a specialist task for a major building, but for a building owner wishing to redecorate, the same principles apply:

1. Walls should also be allowed to continue to breathe. If water does penetrate a wall, sealing with 'waterproof' paints will only temporarily mask the problem or make it appear elsewhere. Breathable paints for both internal and external use are available.
2. The quality of a finished scheme relies on thorough preparation of the surfaces - rubbing down, cleaning, stopping and priming. The top coat will not hide deficiencies in the preparation.
3. Choosing the appropriate paint system for the particular material is vital, including the choice of primers.

Internal paint work varies from simple colour washes to highly decorative tromp l'oeil. Several commercial companies are now offering a comprehensive range of 'historically accurate' paint colours, but for a very intricate and valuable interior, scientific analysis may be necessary in order to reproduce a colour exactly.

Internal timber surfaces in public buildings may need to be treated to reduce the surface spread of flame. This is achieved by applying approved intumescent paints or stains. The work must be carried out in accordance with the manufacturer's instructions in order to guarantee the system meets the required protection level. The work should also be carried out in relatively warm conditions to avoid clouding the varnish.

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Fittings:

Perhaps in Ireland more than elsewhere, the hearth is the traditional centre of the house and even in more modern homes the fireplace is one of the most important architectural features. The fashion in the 1960s and '70s to renovate and modernise, saw chimneys blocked and high quality marble, slate, cast iron and wood fire surrounds discarded. The present owners of many of these house now want to have a real fire and the greatest threat today is the theft and illegal sale of fireplaces to meet a growing demand.

The legitimate salvage trade has however ensured the survival of many of these discarded gems. They are experts at restoring and rebuilding original fireplace surrounds and firebacks, often piecing together broken fragments. They are expensive and will look incongruous in a modern house, but chosen carefully to take account of the age and style of the house and installed correctly, it will add to the value of the property. A good joiner or mason will be able to make a fire surround to fit your requirements exactly and several manufacturers are now producing 'off the peg' ones which may be suitable. The legitimate salvage trade should reveal the source of the fireplace allowing the buyer a clear conscience. Hearths were often slate or stone, again this can be obtained today, often with a metal fender. A dog grate in a firebrick lined recess suits larger rooms, and for smaller rooms, a small fire basket set into a cast iron surround is generally the most appropriate.

Few buildings in Ulster have working external clocks. However, clocks, chimes and bells add a public dimension to a building and where already in place, they should be restored and maintained in working order. Incorporating clocks in new buildings should also be encouraged. Modern technology has replaced labour intensive wind-up pendulums and manually struck bells. There are firms who specialise in the repair and replacement of traditional clocks and for new projects, can offer electronically created chimes and peals.

Interior fittings - the cabinetmakers' skill - are generally outwith the scope of this Directory but occasionally their special skills are used for high quality doors, panelling and fitted furniture in high quality timbers such as walnut, rosewood or maple.

Textile restorers may also be needed to care for fabric panels, curtains and carpets. This is a specialist skill and should not be left to general cleaners.

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Remedial Works:

Building repair technology has become increasingly complex in recent years and there is a confusing array of specialist systems designed to counteract rot, decay and damp. In many cases though, the temptation is to go for a technical solution when perhaps more basic, common sense methods may be less destructive to the building's fabric and occupants and equally effective. Retention of the maximum amount of original fabric must always be the guiding principal. Good remedial specialists should recommend the best system for each individual problem, but a few general guidelines may be useful.

Damp proof courses are rare in old buildings, although a layer of slate or bitumen is sometimes seen running through the wall. Rising damp is often caused when the ground level outside the building is above the floor level inside and dampness is able to penetrate through the walls. Lowering the ground level and providing an external 'french' drain, a perforated pipe laid in a gravel bed around the building to take away excess surface water, and putting in vents to allow ventilation under suspended timber floors will generally alleviate the problem. Gentle background heating inside the house will help to dry out the walls. Most injected chemical DPCs will only work on narrow brick walls. A typical rubble stone wall has voids and rubbish in its core and an injected DPC cannot form a continuous barrier, although specialist grouts are available for filling larger voids. Many old buildings have survived for hundreds of years without a damp proof course but if it is deemed necessary, the best option is an electro-osmotic system, where a titanium wire carrying a very low electric voltage is chased into the plaster around the external walls. Results can be variable on very thick walls, but it is by far the least disruptive method and does not introduce potentially damaging chemicals into the fabric of the building.

Treatment for dry rot, woodworm and other fungal and insect attack is another controversial area. The discovery of dry rot in particular is often accompanied by panic and hysteria. The injection of large quantities of toxic materials and hasty over-zealous remedial work has resulted in the loss of many fine interiors. Dry rot will only survive in damp, warm conditions where there is little air movement, in badly ventilated floor voids and behind window shutters for example. If the source of the water is removed and the ventilation of fresh air improved the dry rot will die. There are few experts who will adopt such a studied yet simple approach. Insurance premiums and demands of mortgage companies often lead to radical stripping out of wholly unaffected timber and plaster which may well be unnecessary. A general change of attitude is long overdue. Good maintenance is the best remedy - gutters should be kept free of leaves and debris, broken downpipes and overflows repaired and pointing and flashings, especially on flat roofs and in hidden valleys, should be checked regularly. Wet rot and woodworm are easily eradicated without great loss of original fabric.

Repairs to chimneys can sometimes seem a black art rather than a scientific process. Flues in old houses were rarely lined and often roof timbers were built into the chimney breast and exposed to smoke. Over the years these can become charred and in some instances can smoulder without detection. This is one of the commonest causes of fires in old buildings, especially if modern closed high output fires burning high temperature smokeless fuel are introduced. This type of fire and 'coal effect' gas fires must always have a lined flue. Inserting a flue liner into an old chimney and filling the voids with insulating material can be a dirty and awkward job and is best left to an expert. Even if the flue stays unlined for an open fire, it is sensible to remove built-in timbers, especially in thatched houses.

Large chimneys are divided into multiple flues which are separated from each other by thin brick divisions called 'feathers'. Flue gases gradually eat away at the brick and can cause the 'feathers' to crack and eventually collapse, blocking a flue or opening a smoke passage from one flue to the next. Bird's nests, accumulated soot and broken 'feathers' can combine to block or even destroy a chimney. Tell-tale signs are smoke coming out of more than one chimney pot when only one fire is lit or smoke coming out of one fireplace when the only fire lit is in the room next door. Coal that is not being burnt correctly in a closed fire will produce invisible and highly toxic flue gases of odourless carbon monoxide which can spread throughout the house if left unchecked. It is always a wise precaution to have chimneys swept annually and to consult a 'chimney doctor' or the Coal Advisory Service if you are lighting fires for the first time or are aware that there might be a problem.

If it is necessary to rebuild a chimney, the original corbelled courses around the top should be replicated and either the old pots or matching new pots reinstated. Excellent reproductions of traditional terracotta pots are available. Redundant flues must be fitted with a ventilated cap to the pots and a grille built into the chimney breast to prevent damp and condensation. Even unused chimneys add great presence to a house and the temptation to demolish them when the central heating is installed should be resisted.

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Services:

The introduction of any new services into an old building demands skill and sensitivity. Considerable ingenuity is required to conceal pipe and cable runs to avoid damaging plaster cornices and skirtings whilst allowing for regular maintenance and access if something does go wrong. Carefully chosen positions for service entry points, soil vent pipes, over-flows and internal fittings such as smoke detectors, radiators and electrical sockets can make all the difference to the visual success of a project. In old buildings this is usually best worked out on site in collaboration with the builder or contractor.

Time and care should be taken in choosing new light fittings, electrical switches and sockets. In the absence of any original light fittings, which could be repaired or matched, these can be either reproduction or modern. Both types can be appropriate, although many off the shelf 'period' fittings are poorly designed. Well made, authentic reproductions are available, but they can be expensive and in many cases, small, discreet modern lights will be more sympathetic to an interior than ornate reproductions. It is possible to adapt brass 'dolly' light switches to modern standards when re-wiring but generally sockets should be replaced and simple, plain fittings are to be preferred. Indirect, diffused lighting is often kinder to old interiors, and early houses which did not have gas or electric lighting may be best respected by using table lamps. Wall lights can avoid damaging delicate or decorated ceilings.

Installing central heating into historic buildings can create problems; drying out timber which leads to panelling and doors warping and causing excessive moisture to be drawn through walls. The absorption and evaporation of water in and out of an old building is generally in a state of balance, this is what is meant by a building 'breathing'. Introducing a new system can upset this equilibrium and central heating should always be used sparingly at first to allow the building to slowly warm up and readjust itself. If extensive restoration is being undertaken, an under floor heating system may be the solution for an early building where radiators would not be appropriate. Second-hand or new cast iron column radiators suit later buildings and decorative radiator cases can be used to advantage.

Thatched buildings must be kept dry all year round and a system of background heating, such as storage radiators should be considered if the building is only used sporadically.

Satellite dishes are totally out of place on historic buildings and indeed putting a dish on a listed building requires Listed Building Consent. Television aerials should be positioned in attics.
It is traditional, through expediency rather than design, to run the electricity supply into a building along the eaves, but in general the common tangle of wires, especially in urban areas, bringing services into a building can mar its appearance and all efforts should be made with NIE and BT to have the cables put underground.

The introduction of complex security systems into historic buildings and compliance with Building Control regulations regarding fire safety and means of escape will often pose difficult problems. Conditions on the Building Control Approval can be amended or waived in certain circumstances and it is always sensible to discuss these issues on site with the official concerned. Most requirements can met with willingness and imagination.

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Specialist Surveys and Photography:

An accurate and appropriate survey of any building is the basis for informed decision-making on a project and is usually the first step in establishing the nature and extent of the work required. Surveys range from simple recording in plan, section and elevation, to highly technical, non-destructive techniques to locate hidden problems.

For most buildings, a traditional, measured survey will be sufficient but care must be taken not to overlook important details. Few old buildings are true and square, and it should not be assumed that rooms are perfectly rectangular - a .series of diagonal measurements will give an accurate picture of the real shape of the spaces, both internally and externally. When extensive work is planned, it is important to record the size, shape and location of all interior fittings such as skirtings, architraves, dadoes, cornices and other mouldings. Once demolitions commence it is more than easy to forget where exactly such items belong: labelling each piece of joinery as it is taken down helps to prevent mistakes later.

Rectified, or corrected photography can be a valuable tool for recording the elevations of large and complex buildings. At its most refined, this technique is called photogrammetry, where the photographic information is stored on a computer disc and used to generate highly accurate drawings in two or three dimensions.

Other tools, such as X-ray, infra-red and ultra-sound can be used to detect hidden problems such as voids or corroded metal fixings within the fabric of the building itself. The most common are magnet-based 'cover meters' and impulse radar. The successful use of these techniques requires specialist advice, and they are normally only employed on the most intricate and important of structures where the high cost can be justified. However, such costs may be offset by the early identification of problems before they become serious defects, requiring major intervention to remedy.

Access for surveying is often a problem and the cost of scaffolding can greatly outweigh the cost of the survey. Mobile hoists are in general use, but for very awkward buildings, roped access techniques are often more effective, allowing even the most hidden parts of a building to be thoroughly investigated and recorded.

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