Guidelines and Technical Advice for Works on Historic Buildings

This advice and guidance is concerned with works that affect the special interest and character of listed and historic buildings.

Some of these works could require Listed Building Consent. Please always consult with us if you are unsure if the works you propose to carry out to a listed building may require consent.

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They summarise the characteristics and features, which make up the special interest of most listed and historic buildings. This should be given full weight in the process of judging any proposed works and LBC applications.

However they are not a manual of repair and should not be used as such.

Please use the links below for more information on each topic.

Other useful sources of information

We have also published a document called Looking after your historic building, available here in five parts: part 1part 2part 3part 4part 5.

Technical advice and best practice for works to historic buildings can be found on the Historic Environment for Local Management (HELM) website which includes information and guidance available from English Heritage, local authorities, amenity groups and relevant bodies.

The Society for the Protection of Ancient Monuments website provides a variety of technical services and resources for the general public to encourage excellence in the restoration and repair of historic buildings.

Old buildings porous nature allows water absorbed by the fabric to evaporate back out. As a result lime-based materials should be used as they allow structures to breathe.

In contrast modern cement is an impervious product that forms waterproof barriers that restrict evaporation, and is therefore an inappropriate material for use in old buildings.

Limewash

Limewash is a simple type of paint made from lime and water, and is available in various colours. The benefit of limewash is that it allows solid walls to breathe and retains the texture of any underlying stone. 

It can be used externally and internally and is suitable over lime plaster or render, earth and stone walls, timber and most old limewash.

Limewash is however unsuitable for impervious materials that fluid cannot pass through such as flint or hard brick, and is also not suitable on sandstone.

Repointing should ideally not be carried out until the mortar has weathered back to a depth equivalent to the joint width, or is very loose.

In old buildings a lime mortar should be used, as being more permeable than stone or brick it allows the building to breathe. Modern cements produce a hard finish, which produces an impervious waterproof surface that often damages the softer masonry. It can also sometimes result in external cracking and internal damp, so should not be used.

All attempts should be made to match the new pointing with the style, texture and colour of the original, unless that is inappropriate repointing itself. The production of mortar samples and trial panels is strongly encouraged.

Pointing should only be cut out by hand. It should not be cut out with mechanical cutters, such as angle grinders etc, as this makes the joints unacceptably wide, and may score the masonry.

Where possible repointing in the winter should be avoided. Whatever the time of year you must ensure new work is adequately protected from frost, rapid drying (by the wind or sun) and rain.

Stone, Brickwork, Cob etc

Walls are the main structural fabric of a building. Alterations to wall surfaces are usually the most damaging that can be made to the overall appearance of a historic building.

External alterations or repairs should respect the existing fabric and match it in materials, texture, coursing, quality and colour. Ideally a sample panel of any new external walling should be initially built to ensure that these concerns are satisfied.

Stonework or brick should not normally be rendered unless the surface was rendered originally.

Every effort should be made to retain or re-use facing stonework, brickwork, slate hanging, weatherboarding etc.

Any new materials that may be required should be carefully sourced to ensure that they match, as close as possible, the existing original texture, coursing, quality and colour.

Cob and other earth walling should be carefully maintained. Expert advice should be taken if there is a need for repair.

Cleaning Stone and Brickwork

Cleaning is justified in certain circumstances, but in many cases will do more harm than good. It risks damaging the stone and brickwork, can remove a building's sense of history, and may bring only short-term benefits.

Cleaning can be appropriate when there is a need, for example, to remove inappropriate paint finishes, graffiti or very heavy soiling.

The method(s) of cleaning must be carefully chosen in consultation with a specialist.

  • Abrasive techniques will probably remove the protective fire skins from the bricks, leaving the softer inner parts vulnerable to decay.
  • Water-based methods can sometimes cause unsightly efflorescence (white deposits) or damp penetration.
  • Chemical cleaning can sometimes produce staining if not properly washed off.

The method of cleaning must be appropriate to the type of stone or brickwork, so an on-site trial should always be conducted first.

External Painting and Finishes

Cement based or other waterproof and hard gloss paints should not be used on surfaces covered with traditional render.

The correct finish for stonework, traditional renders and plasters is limewash (although much 19th century stucco has traditionally been coated in oil paint).

When inappropriate paint has been applied, expert advice should be obtained on suitable methods of removal.

Repainting with lead-based paints may be historically correct, but is now restricted to Grade I and II* buildings and the intention to use it on any such building must be notified to English Heritage

Timber Frames

With timber-framed buildings, the complete structure has to be taken into consideration, i.e. walls, roof and internal partitions.

Repair to timber frames, including roof structures, should be kept to the essential minimum. Traditional fixing and repair methods should be continued.

Proper attention should be given to the in-filling panels which are an integral part of any timber-framed building, and also to the surface of the timbers.

The original tool marks are often visible, as well as carpenters' marks, graffiti and smoke-blackening. Such features are always destroyed by sand-blasting and sometimes by painting or other cleaning, which should not normally be permitted.

Door and Window Openings

Door and window openings establish the character of an elevation and should not generally be altered in their proportions or details, especially where they are a conspicuous element of the design.

The depth to which window frames are recessed within a wall is a historical feature of importance and greatly affects the character of a building. These should also be respected.

Any proposed new door or window openings should ideally incorporate the same details, features and materials of any original existing examples i.e. granite lintels, sills, quoins etc.

The installation of plastic (UPVc) windows or doors in listed buildings is not acceptable.

As the thickness of frame members tends to be greater in plastic windows than in traditional timber ones it almost always damages the character and appearance of historic buildings. Therefore timber windows, doors and frames should be installed.

Also, it is usually impossible to install double-glazed units in existing frames or to replicate existing frames with new sealed units without making noticeable changes to the profiles of glazing bars, stiles and rails.The new glass in such units may also significantly alter the appearance of the window.

Such changes are rarely acceptable in listed buildings, therefore in almost all cases single glazing should be used in listed buildings.

Draught-proofing and weather stripping are visually more innocuous changes, as well as being thermally efficient and cost-effective. Secondary glazing in a removable inner frame is another acceptable option for some windows.

Additionally internal timber shutters are another alternative, and were often originally part of many historical buildings.

Windows

Old windows are a key feature in historic buildings, contributing massively to a buildings architectural importance.

As a rule, windows in historic buildings should be repaired, as repairs retain original fabric. If beyond repair they should be replaced like for like.

Sash windows, which are regularly found in local old buildings, can be overhauled. There are many good companies that specialise in this type of work.

In many cases only a part of a window will need repairing e.g. the sill, frame etc. An added benefit of keeping old windows is that the timber used is frequently superior to that used today and often results in lower long-term costs and maintenance.

Any old glass and ironmongery should ideally be kept, as they are another important aspect of a buildings character.

Technical advice and guidance on the maintenance, repair and design of windows, that will preserve or enhance the character of a historic settlement, is available for Camelford in North Cornwall.

Doors

Original doors are an important aspect of the character and authenticity of a building.

Existing doors can frequently be repaired, and replacement should therefore be a last resort.

If renewal is unavoidable they should be like-for-like in terms of style, materials and finish.

Old door furniture should ideally be retained as old knockers, knobs and locks etc can make a small but valuable contribution to a buildings quality. This also applies to features such as fanlights, pediments, columns, pilasters, cornices etc. 

Window and Door Finishes

Paint is usually the correct finish for timber windows and doors. Staining is not a traditional finish and should not normally be used.

Early windows of oak were commonly limewashed or left unpainted and these should not now be painted but left to weather naturally.

The roof is nearly always a dominant feature of a building and the retention of its original structure, shape, pitch, cladding and ornament is important.

Slate

The character of slate roof coverings should not be damaged, with the patterning and coursing being retained and, where necessary, restored with matching materials.

Consideration should normally be given to re-slating when repairs are no longer cost effective.

The local vernacular style of slating is often wet or dry laid scantle, incorporating diminishing courses and random width slates and should ideally be replaced like-for-like.

Other natural slates are considered for re-slating, with each application being treated individually.

All attempts should be made to salvage and re-use as many old slates as possible.

New slates should match the type, colour, texture, size and thickness of the existing examples as close as possible. Slates should preferably be fixed with either timber pegs or copper nails. Ridge and hip tiles should, in most cases, be made of clay and be angular in design

Thatch

When roofs are re-thatched, this should normally be done in a form of thatch traditional to the region, and local ways of detailing eaves, ridges and verges should be followed.

It is important to keep lofts draught-free and clear of old thatch and other combustible material.

Chimneys in use should ideally be swept twice a year and the stack should carefully be monitored, especially in the roof space. It is important to promptly address any concerns with a competent Thatcher.

Chimneys

Chimney stacks are both formal and functional features of the roofscape, and can be important indicators of the date and internal plan of a building.

In many cases chimneys perform a vital structural function and also act as a form of ventilation. They should therefore ideally be retained, even when no longer required.

Chimney pots can sometimes be valuable decorative features in their own right, and are also functional features of a building.

Rainwater and Ancillary Goods

It is important to maintain gutters and ancillary items such as flashings in good working order. The emphasis should be on matching details appropriate for the locality and building's age.

The detailing of existing hips, valleys, ridges, dormers, eaves and abutments should therefore be recorded before any works are carried out to them.

Ideally, cast iron or aluminium gutters should be used.

When fixing rainwater goods to agricultural buildings, brackets should be used instead of fascias. Brackets should also be used as fixings if the use of fascia boards would obscure original lintels.

Rainwater goods are usually best painted in unobtrusive colours.

Technical advice and guidance on the maintenance, repair and design of roofs, that will preserve or enhance the character of a historic settlement, is available for Camelford in North Cornwall.

The plan and footprint of a building is one of its most important characteristics.

Interior plans and individual features of interest should be respected and left unaltered as far as possible.

Internal spaces, staircases, panelling, window shutters, doors and door-cases, mouldings, decorated ceilings, stucco-work, and wall-decorations etc are part of the special interest of a building and may be its most valuable feature.

There are some standard external fixtures to historic buildings that require careful consideration as they can often affect their character.

These include:

  • satellite dishes
  • meter boxes
  • burglar alarms
  • security and other floodlighting
  • video cameras
  • central heating and other flues, both standard and balanced.

Undamaging fixings and visually unobtrusive positions should therefore be found.

The poorly thought out introduction of services, such as mains electricity, telephone or gas, can be detrimental to the structure, appearance and character of a building. Long runs of surface wiring and any external gas piping should be avoided unless chasing-in would destroy historic fabric.

The introduction of new services to historic interiors must also be handled with care, and any false floors or ceilings for concealing services, computer trunking.