Watch a video clip about the difference between traditional plasters and modern plasters.

Advice & Guidance

Inside the Building

Evidence of dampnessInternal walls: The first point to consider is that all old buildings will be damp to a certain degree. Their method of construction means that they are designed to accept moisture and then to allow this moisture to evaporate when the conditions are right.

However, if there is a possibility of excessive damp, it needs to be very carefully investigated to determine the cause.

Excessive damp will often be the result of a failure of rainwater goods or the build-up of ground levels around the building but it may be less straightforward. Begin by eliminating any obvious causes such as leaking pipework or a failed roof covering and work systematically through the potential contributory factors.

Damp in wallRemember that staining or mould growth on walls may also be caused by condensation. Once the cause has been identified, appropriate remedial action can be taken.

Action point: If you identify any new stains or damp patches, start by trying to identify the cause. Simple faults such as blocked gutters should be rectified immediately. However, if there is no obvious cause, consult your professional advisor.

Floors: The traditional flooring material for churches in the medieval period would have been stone slabs or clay tiles, though the earliest churches may have had beaten earth floors. Generally speaking, stone slabs and clay tiles were laid directly onto compacted earth and allowed moisture to pass through them. As such they were able to 'breathe' in the same way as traditionally constructed walls. The idea of using a damp proofing material to prevent moisture penetrating though the floor has only been part of normal construction practice since 1875.

Medieval  tilesTimber floors are also a common sight in places of worship and may be a feature of post-medieval alterations to the building.  Even where timber floors or pew platforms were installed the use of stone slabs or ceramic tiles for the aisles and sanctuary areas continued. The 'reinvention' of encaustic tile making in the Victorian period was perhaps a particular highlight of the renaissance of church building in the nineteenth century.

Old stone or tiled floors should not be sealed with wax or oil or covered with rubber or foam-backed carpet as they need to be able to ‘breathe', but do monitor wear and tear and ensure that they do not present a hazard.

Stone slabsLook out for loose flags or tiles and any worn, chipped or delaminated areas that require attention from a skilled craftsperson to prevent the deterioration accelerating.

Remember that historic floors may have important features, such as old encaustic tiles, ledger stones or brasses. These need special care, so seek advice on the best means of their protection.

Action point: Stone, marble and terrazzo floors should only be cleaned very occasionally with a damp mop, rinsed with clean water and dried off with a dry mop. Use minimal quantities of cold or warm (not hot) water and a little pH neutral soap if necessary.In between times, such floors should simply be swept clean.

Action point: Floor tiles can be lightly washed with clean water. If the tiles are glazed, they can be washed with a mop and water to which a small amount of pH neutral detergent has been added.

Wash off with clean water and dry with a soft cloth. Try not to use too much water and be aware that excessive washing can cause damage to the surface of the tiles. Loose grit and dust should be removed by vacuuming or sweeping to prevent it scratching the surface of the tiles.

Victorian tiles

Many places of worship have suspended timber floors or pew platforms with a void beneath them. If there is a void, you should check that any air bricks and ventilators at the base of the walls or in pew kerbs are kept clear to allow air to circulate freely under the floor.

FloorboardsThis will decrease the likelihood of dampness and associated fungal rot or insect infestation. If you suspect that there is timber decay or possible insect infestation in your building, seek advice from your architect or surveyor, rather than someone with a vested interest in a method of treatment.

Wholesale timber treatment with chemical preparations is rarely necessary but independent advice from a timber specialist (rather than a treatment company) may be required. Remember that worn floorboards or those with old evidence of beetle attack do not necessarily require repair. Any gaps or loose floorboards can be repaired by a skilled joiner.

ParquetAction point: Existing polished wooden floors should be dry polished from time to time. You can also use a (lint free) woollen cloth impregnated with a mixture of paraffin and vinegar in equal proportions to collect dust and leave the floor shiny. Unpolished floorboards should only be washed when absolutely necessary.

Use minimal quantities of cold or warm (not hot) water and a little pH neutral soap if necessary.


Rinse the area with clear water and dry off with a dry mop. Also, remember to ask your cleaning team if they have swept up any insect debris. Evidence of insect attack is often cleaned away and not reported.

Sheet materials such as carpet or vinyl can become a tripping hazard if they are loose or worn. Areas of particularly heavy use such as toilets and kitchens will need frequent attention.

Ceilings: Not all places of worship have ceilings. In many cases, the underside of the roof structure is visible from below. Inspect the ceiling or the underside of the roof thoroughly, using binoculars and a flashlight if necessary, as stains and damp patches on the plaster or timberwork may indicate a problem that requires further investigation. However, some stains may relate to a previous fault that has now been fixed. If the stains are new, the cause is likely to be a slipped slate or tile or a split in the leadwork. Where the ceiling is directly attached to the underside of the rafters, cracking can sometimes indicate problems with the roof structure.

Painted boarded ceiling Timber ceiling

Action point: If you observe new stains on the ceiling or the underside of the roof structure, consider carrying out an inspection of the roof covering. If access is safe, you may be able to so this yourself, otherwise you may need to consider obtaining the services of a professional.

Further information

© SPAB 2010