10 Ways to Ruin an Old Building

Jonathan Taylor

1 Employ consultants and contractors who do not specialise in historic building work

The importance of old buildings is not in question. Historic town and city centres across the British Isles attract millions of visitors every year, and houses within areas that contain few post-war alterations command significantly higher values than similar houses in areas which are broken up by modern developments. Their appeal lies not only in their sense of history but also in their visual character and interest: the rich variety of colour, texture and form, the individuality of natural and hand-made components, the abundance of intricate details from fine glazing bars to decorative railings and street furniture, and the softness of mature landscaping.

Despite extensive redevelopment which damaged so many historic centres, particularly in the 1960s and ‘70s, almost all our towns and cities retain pre-20th century historic cores, and around one in five buildings today pre-dates 1914. In those urban centres where historic integrity is strong, the character is maintained not only by planning control but also by peer-pressure and increasing recognition that insensitive alterations will damage the financial value of the owners’ properties. However far more old buildings have been hidden under a veil of alterations, and in many cases poor alterations and a lack of maintenance threatens their survival.

Today major redevelopment in historic centres is rare, and the greatest threat comes from the small, insidious ‘improvements’ often made by well intentioned but misinformed owners, their contractors and consultants, as well as from a lack of regular maintenance. Traditionally constructed buildings do not perform in the same way as modern ones and need to be treated differently, at every stage of their conservation and repair. Modern materials and construction techniques are often incompatible with traditional ones, and repairs which are suitable for modern buildings can lead to the deterioration of historic building fabric. Relatively few contractors and consultants have the expertise required to deal with the special problems of historic buildings, and even relatively harmless techniques can damage historic materials in the wrong hands.

A few simple alterations have made one half of this attractive Victorian house look modern, and the loss of the garden and its front wall have added to the erosion of a conservation area (Kit Wedd)

2 Do not carry out any essential maintenance work

If huge repair bills are to be avoided and important historic fabric protected, owners need to clear gutters of leaves in the autumn; roofing slates and tiles need to be replaced, flashings maintained and chimneys pointed and capped to prevent water entering the fabric of the building, causing decay.
Air bricks and vents need to be kept clear of weeds to ensure that cellars and sub-floor cavities are kept well ventilated to prevent condensation, which also causes decay.
Pipes, washing machines, shower trays and other potential sources of water within the building need to be checked for leaks for the same reason.

Visible signs of decay caused by poor maintenance

3 Use cement in place of lime for mortars

Masonry which is traditionally constructed is bedded in soft lime mortar and is relatively flexible: pointing with a hard cement restricts its movement, causing stress in the surface of the wall where it is bound by the cement, and the face of soft stone and brick will fail as a result.
Cement mortars are also impermeable - that is to say that they do not allow the structure behind to 'breathe': moisture is forced to evaporate through the stone or brick, and in extreme cases may cause these materials to deteriorate.
Cement mortars may also be visibly different, both in colour and detail: being hard they can be made to project forward from the face of the wall, or may be smeared across the edges of stones, changing the appearance of the wall as a whole.

A timber framed house with panels re-rendered using a hard cement; the panels allow rain to penetrate the walls at their junction with the exposed timbers but the hard render restricts its evaporation, causing extensive decay (Robert Demaus)

4 Paint or coat surfaces which were originally left natural

Cementitious coatings and most modern paints and stone consolidants are not porous and will lock moisture in the walls: evaporation is concentrated at cracks where any salts present crystallise, causing decay.
Damp patches may appear on the inside wall as more moisture is forced to evaporate here.
Certain materials will deteriorate rapidly as a result of the increased moisture levels, including cob, daub and other earth mixtures, and timber is more likely to rot.
All non-original coatings hide the original colour and pattern of stone and brickwork and modern coatings and claddings such as stone cladding, pebble-dashing, and other modern cementitious coatings make old buildings look (at best) modern and ordinary.

Evaporation of moisture from a wall is concentrated by an impermeable coating at cracks, leading to localised stone decay due to salt crystallisation. The use of colour to emphasise the drain pipe is also questionable

5 Extend or alter the accommodation in a manner which conflicts with its style

Badly designed extensions can dominate the existing building by virtue of their size or style, or a change in material or finish.
Internal alterations which involve the loss of the original layout of rooms, decorative features or principal features such as fireplaces and staircases damage the character of the interior.
Covering the garden with tarmac to create forecourt parking damages the townscape and the setting of a building.

This early 18th century cottage with dressed stone windows has been altered and extended many times this century, most recently with the top-heavy dormer windows and the porch (see next illustration)

6 Introduce mix-and-match ‘period style’ detail

The addition of reproduction features for uses never originally intended, such as 'carriage lamps' on either side of a front door, external shutters particularly where they are fixed to the walls and clearly serve no functional purpose, and ‘bulls-eye’ glass panes make old buildings look cheap and phoney.
Poor 'period-style' features such as front doors with press-moulded panel mouldings, black rubber seals, fanlights within the door itself, stuck-on strips in imitation of leaded lights, and other fancy details look incongruous in a genuinely historic building.
The ‘restoration’ of features where they never existed confuses the history of a building; for example, the introduction of fine plaster mouldings in attic rooms, basements and other rooms where features were once simple and functional.

These details have been chosen to look 'quaint’, but would be more in keeping with the character of a modern housing estate than this 18th century cottage

7 Replace original components unnecessarily

Replacement windows are rarely necessary: decay is usually limited to the bottom few inches of the frame and new timber windows are liable to decay more quickly than the originals would if repaired.
The removal of all timber within one metre of any visible sign of dry rot (which is still advocated by many) is excessively devastating and unnecessary as the reintroduction of dry, ventilated conditions alone will prevent its growth.
Old and original structures which have distorted through old settlement and are now stable may need repair, but rarely need to be replaced.
Replacement plastic windows in particular (see 6 & 7 above) fail to match the appearance of old windows: they invariably have larger, heavier sections than timber windows; black rubber gaskets are visible around the glass; and fine glazing bars cannot be incorporated convincingly. Their claim to be 'maintenance-free' is also misleading as plastic, like paint, becomes scratched and disfigured by dirt in time, and it will eventually need to be painted regularly to maintain its appearance.

New plastic windows in particular detract from the character of old buildings

8 Position modern services and equipment intrusively

Satellite dishes, air-conditioning units and extractor fans are alien features, which, where necessary, can usually be positioned discreetly.
Electricity wires, telephone cables, lightning conductors and other services need to be installed tidily without snaking across walls and decorative features; careful planning may avoid the need to chase service runs into the original structure.
Modern fixtures such as radiators, smoke detectors and other interior service fittings can be painted to blend with the prevailing colour of the wall to which they are fixed, and in some cases may be hidden altogether without affecting their performance.

Satellite dishes need to point in a particular direction, but they do not need to be on the front of a house, nor do they need to be coloured black

9 Use cleaning methods which damage original surfaces

Sand-blasting and even the most gentle air abrasive cleaning can remove the surface from stone or brick, particularly in the wrong hands and should never be used on timber.
Chemical cleaning agents such as acids and alkalis react with stone and brick as well as dirt layers, causing damage, and all can leave harmful residues behind
Water even under low pressure soaks masonry and can cause surface staining and efflorescence (salt crystallisation), and in the worst cases may lead to the decay of masonry.
Paint-stripping doors by immersion in a caustic bath damages wood and removes glue from joints.

Dipping in a bath of caustic soda is by far the cheapest way to paint-strip doors, but also the most damaging to the timber and the joints in particular

10 Overload an existing structure

Replacing slates with concrete roofing tiles can cause rafters to bow and even collapse under the increased weight unless the structure is reinforced.
Underpinning part of a building can move loads onto other parts of the structure, exacerbating settlement damage, and is often carried out unnecessarily.
Removing low ties of a roof truss (the horizontal beams which run at eye-level across the attic, at right angles to the ridge) can cause the roof to spread and collapse.
Removing chimney breasts, walls and other structural features can also damage the structural integrity of the building.

The tie beams literally tie the two sides of the roof together. Their removal to make an attic usable can lead to the collapse of the roof (the location of the tie beams removed in the past is indicated by the dotted lines)

THE CAREFUL ALTERNATIVE

CONSERVATION

Taken out of context, this long list of don'ts would no doubt cement many people’s view that conservation is all about freezing buildings and places in a perpetual time warp at the expense of any function. However, conservation encompasses a broad range of measures and approaches to historic buildings, and at its best conservation is an extremely creative process.

Within the field of building conservation, the term 'conservation' may be defined as the process of protecting a building and its surroundings from any change that might involve a loss of historic fabric, historic importance or character. This process is made more complex by the fact that most buildings have an active function, and the need to accommodate the function is a recognised facet of building conservation.

A distinction needs to be made between conservation, preservation and restoration, which are often erroneously used to mean the same thing. In the field of building conservation the term 'preservation' is generally used to distinguish a particular type of conservation work sometimes referred to as ‘conservation as found’, in which the fabric is preserved in the state in which it was at the start of the project. Conservation, on the other hand, may involve an element of alteration, for example; to maintain the functional use of the building, or to prevent its further decay.

Restoration is another term used erroneously to mean conservation. Here the issues are more complex, since some restoration work may involve stripping away historic alterations to reveal earlier fabric, and in most restoration work new material is introduced to match missing components. In this respect the aim of restoration is clearly different from that of conservation, and some restoration work may actually damage the historic character of the building. Nevertheless, most conservation work involves some element of restoration, particularly where essential repairs are carried out to match the original form of a decayed component, where the aim is primarily to conserve fabric.

Although conservation does not mean freezing a building in its present state for perpetuity, it does mean that all alterations must be carefully justified beforehand, taking into account not only the affect of the works in the short term but also their consequences for the building, its character, historic interest and its functionality in the future. Historic architecture can often be adapted to meet modern requirements without loosing any historic fabric or with alterations which are designed to be 'reversible'. Where buildings which are listed or in conservation areas are concerned, the degree of alteration permitted by local authorities will vary according to the importance of the building and the components affected and how essential the alteration is to the function of the building.

Developing a caring approach to old buildings is essential to the whole community. Historic architecture affects us all, whether we live in an old building or neighbourhood, shop in historic urban centres, or enjoy sightseeing. Neglect, decay and insensitive alteration has a real impact on the quality of our surroundings.

This article is reproduced from The Building Conservation Directory, 1998

Author

JONATHAN TAYLOR is the editor of The Building Conservation Directory and a co-founder of Cathedral Communications Limited. He studied architectural conservation at Heriot-Watt University, Edinburgh and has a background in architectural design, conservation and urban regeneration.

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