Advice for works to historic buildings

Cornwall Council, Town and Parish, and the Police and Crime Commissioner elections information and results.


This page is about carrying out works:

  • to historic buildings and
  • in historic places. 

Works to Listed Buildings may need Listed Building Consent. External works to buildings in a Conservation Area may need planning permission. 

Our Do I need planning consent or building regulations? service can help you check.

The contents link to our information on:

  • historic building techniques and materials and
  • external sources of information 

Other sources of information

External Walling

Stone, Brickwork, Cob etc

Walls are the main structural fabric of a building. Changes to wall surfaces affect the appearance of a historic building. As such, the selection of a suitable contractor is the most important decision.

External alterations or repairs should match in materials, texture, coursing, quality and colour. Development officers may ask for a sample panel of any new external walling.

Re-use facing stone, bricks or slates where possible.  Every effort should be made to retain or re-use facing:

  • stonework
  • brickwork
  • slate hanging
  • weatherboarding etc.

Consider the existing original texture, coursing, quality and colour when introducing new materials.

The maintenance of cob and other earth walling is imperative for its longevity.

Cleaning Stone and Brickwork

Cleaning can do more harm than good but may be necessary in certain circumstances.

Cleaning can be appropriate when there is a need to remove poor paint finishes or graffiti.

Consider the method(s) of cleaning in consultation with a specialist. It should consider the type of stone or brickwork. Perform small on-site trials.

  • Abrasive techniques remove the protective fire skins from bricks. This leaves the softer inner fabric vulnerable to decay.
  • Water-based methods can cause efflorescence (white deposits) or damp penetration.
  • Chemical cleaning can produce staining if not well 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.

Pointing

Repointing is necessary when the mortar has weathered below the face of the stone or is very loose.

Historic buildings need lime mortar, allowing the building to breathe. Contra, modern cement forms an impervious surface. It damages soft, historic masonry and holds moisture in the stone.

The removal of pointing with mechanical tools can damage the stone and widen the joints. Only hand tools are suitable. Development officers may ask for a method statement to describe the works step by step.

Pointing should match the style, texture and colour of an original quality finish. As such, development officers may request the following details:

  • specification of aggregate
  • specification of mortar
  • sample photographs of trial panels.

Protect new lime pointing from frost and rapid drying (by the wind or sun) and rain. Avoid repointing in the winter where possible.

External Painting and Finishes

Avoid cement based or hard gloss paints on traditional render.

Limewash is often the correct finish for stonework, traditional renders and plasters. 

Seek expert advice to remove inappropriate paint.

Some listed buildings still use lead paint: Paint Legislation and Historic Buildings. If you are restoring a Grade I or II* listed building you need to notify Historic England to use lead paint. For more information, follow this link:

Sourcing Lead Paint | Historic England

Lime in Old Buildings

Historic buildings need to breathe. Any water absorbed by the fabric needs to evaporate back out. Lime-based materials allow structures to breathe.

Cement render and paint prevents this evaporation and can lead to internal damp.

Historic Environment for Local Management (HELM)

Limewash

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

Limewash is suitable for historic building materials:

  • lime plaster
  • render
  • earth
  • stone
  • timber.

Limewash is unsuitable for impervious materials:

  • flint
  • hard brick.

It is also not suitable on sandstone.

Timber Frames

The individual parts of a timber-framed building are interdependent.

Necessary repairs should use traditional fixing and methods.

In-filling panels are an integral part of any timber-framed building.

Original tool marks, carpenters' marks, graffiti and smoke-blackening are valuable. Practices like sand-blasting removes these distinctive characteristics.

Windows and Doors

The size, proportion and position of openings give clues about the history of a building.

Windows are the eyes of a building. We take in a lot of details without realising and this forms our impression and the character of a building. The following are important details:

  • the size, proportion and position of the opening
  • lintels, sills and quoins
  • the depth a frame is set into the opening
  • the material and section of the frame
  • pattern, thickness and section of glazing bars
  • thickness of the glazing.

Repairing or replacing windows

The timber in historic windows is slow grown and high quality. A joiner can often repair them. You need a joiner's report to get Listed Building Consent to replace them. When a joiner confirms they are 'beyond repair', replace them 'like for like' (see the details above).

Re-use historic glass or ironmongery, another important aspect of a building's character.

Follow these links for more information on traditional windows:

Historic England - Windows - their care, repair and upgrading

Technical advice and guidance on the maintenance, repair and design of windows

Doors

Original doors and their detailing contribute character and authenticity to a building.

As with other historic joinery, repair existing doors. Replacement 'like for like' is a last resort (see the details above to understand 'like for like'). Details particular to doors are features like:

  • fanlights
  • pediments
  • columns
  • pilasters
  • cornices.

Door furniture like knockers, knobs and locks can often be re-used.

Window and Door Finishes

Apply linseed oil to protect timber.

Suitable paint types can form a protective finish for timber windows and doors. Staining is not traditional.

Leave oak windows untreated and weather to silver.

Roofing

The roof is a dominant feature of a building. Its original:

  • structure
  • shape
  • pitch
  • cladding and
  • ornament are important features.

The selection of a suitable contractor is the most important decision.

Slate

The type, patterning and coursing of slate contributes to its distinctive character.

The local vernacular style of slating is often wet or dry laid scantle. Like for like will note detailing like diminishing courses and random width slates.

Re-use slates and ridge tiles where possible.

New slates should match the:

  • type
  • colour
  • texture
  • size and
  • thickness.

Fix slates with timber pegs or copper nails, not clips. Ridge and hip tiles are often clay and angular in design.

Thatch

The type and detailing are particular to an area. Re-thatch in the local ways of detailing eaves, ridges and verges.

Maintain chimneys and check the stack often.

Chimneys

Chimney stacks are formal and functional features of the roofscape. They can be important indicators of the date and internal plan of a building. Chimney pots are functional as well as decorative.

Chimneys are often structural and provide ventilation. So, keep the stack even when they are no longer functional.

Rainwater and Ancillary Goods

Maintain gutters and ancillary items such as flashings. Failure to do so is the most common cause of damp to historic buildings.

Record the following details before doing work:

  • hips
  • valleys
  • ridges
  • dormers
  • eaves and
  • abutments.

Cast iron or aluminium gutters are suitable for historic buildings.

For agricultural buildings, use brackets instead of fascias to fix rainwater goods. For historic buildings fix with brackets if fascia boards would obscure original lintels.

Rainwater goods are usually best painted in unobtrusive colours.

Follow this link for more information:

Technical advice and guidance on the maintenance, repair and design of roofs.

Interiors

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

Leave Interior plans and historic features of interest unaltered as far as possible.

Minor Additions and New Services

The following are external fixtures that  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.

Consider the fixing and position of these additions.

New internal services are likely to need Listed Building Consent.

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