Advice & Guidance
Paint
Traditionally,
external oak doors were left untreated though there is some evidence
that they
may once have been limewashed. Though
some people now favour regular treatment with linseed or tung oil this
is not
always necessary. Left to its own devices oak will weather to an attractive
silvery
grey colour and will withstand the elements quite adequately.
On the other hand, softwoods, such as pine and fir, which were commonly used from the Georgian period onwards, are generally less durable and need to be painted to protect them from decay.
In the past, builders and joiners would have used lead paint to protect such surfaces. Lead paint comprises lead pigment (usually lead carbonate - known as ‘white lead') bound in oil.
This
white coloured paint could be used
in its natural state or tinted with various pigments. Historically, linseed oil was used as the
binder with turpentine added to determine the required finish - either
matt or
semi-gloss.
Lead paint was popular until the 1960s, particularly on timber and metalwork. However, toxicity concerns mean that the supply of lead carbonate based paint is now restricted by law for use on certain listed buildings, scheduled ancient monuments and works of art.
Where care is taken, its careful application is still a valid choice, especially for the protection of C18 and C19 joinery and the conservation of important historic interiors.
However, those responsible for the fabric of places of worship do need to be aware of the risks that arise from the inappropriate sanding down or removal of lead paint during redecoration, as older painted surfaces may well include many layers of lead paint.
Dealing with old lead paint
Consider whether your
building might have
surface finishes containing lead paint. Old
lead paint frequently has a creamy or soft colour and rather than
splitting and
peeling, it may develop a fine, rectangular pattern of
cracking.
The presence of lead paint can be confirmed
with a DIY test kit or by professional analysis.- If you think that lead paint may be present, consider how to approach any necessary redecoration. It may be safer to renew or overcoat lead paint than to attempt its removal. Seek advice from your professional adviser if necessary.
- Ensure that any volunteers, craftspeople or professionals undertaking the removal of lead paint have carried out a thorough risk assessment and put in place appropriate safety measures.
- Be aware that children are particularly vulnerable to lead poisoning.
Choosing a paint system
Lead paint: If your building is Grade I or II* listed (Categories A, B and C(S) in Scotland) you are permitted to use traditional lead paints, although their use is strictly controlled by the Environmental Protection (Controls on Injurious Substances) Regulations 1992.
The benefits of lead paint are its unrivalled durability on timber, its flexibility and its ability to ‘breathe'. Its texture, depth of colour and mellow
appearance are also difficult to emulate with newer alternatives and it emits
less environmentally harmful volatile organic compounds (VOCs) than
modern
oil paints.
However, if your building is not Grade I or II* listed or you are concerned about the toxicity of lead paint you might consider using one of the following alternatives:
Linseed oil paints: These paints have been in use for many years and are both durable and aesthetically pleasing. Most are also solvent free.
The downside of linseed oil paints is that they take quite a long time to dry and require some skill to apply successfully.
Water-borne acrylic paints: These paints can be glossy or matt and do not contain solvents. They tend to be quick-drying, flexible and easy to use although they need to be applied to clean wood, which is free of old failing paint layers, to achieve their best performance.
If you are unsure about the most appropriate choice of paint for your building seek advice from your professional adviser.
Caring for external painted timber surfaces
Painted external joinery can deteriorate rapidly if paint finishes are not maintained. You should inspect all external timberwork, including any fascias and bargeboards, annually.
Take note of the condition of any paintwork. Blistered or flaking paint will allow water to penetrate into the timber where it may become trapped, leading to decay. Also look closely for any signs of cracked and rotten wood.
Action point: If areas of softwood have previously been painted, make sure that the integrity of the surface is maintained. This will probably mean repainting external timberwork every few years. The frequency of any repainting will depend on the paint system chosen and the exposure of the site.
Further Information
Further information about lead paint can be found in SPAB Technical Q&A 30: Lead Paint on the SPAB website.
'Paint, Wood and Weather' by Colin Mitchell-Rose is available on the Building Conservation Directory website.
'The Case for Micro-porosity – does it hold water?' by Peter Kaczmar is available on the Building Conservation Directory website.
The Health and Safety Executive (HSE) has a new section on its website devoted to advice about lead safety.
The British Coating Federation (BCF) offers advice on dealing with old lead painted surfaces in its guidance booklet.
© SPAB 2010
