Painting Best Practice – [Timber]
There are two main classifications of timber, i.e. softwoods and hardwoods.
Softwoods come from coniferous trees (cone bearing) while hardwoods from deciduous trees, (broad leaved).
Softwoods are not durable when used externally, unless protected by a suitable wood preservative, followed by a paint, woodstain or varnish system.
Hardwoods are more durable generally and do not require preservative treatment. However, oily
types do require pre treatment with solvent to remove oily residues.
Ensure surfaces are dry, clean and free from dirt, oil, wax, polish, etc before priming and painting.
Moisture content should not exceed 18%.
Double check all vulnerable areas of old paint for adhesion, i.e. lower rails, cills, etc., and completely
remove coatings from these sections if condition is poor.
Check for any defective putty or beadings.
Allow new putty to form a hard skin before painting.
Use a suitable proprietary wood preservative on non durable, non pre-treated softwood.
Oily hardwoods should be wiped over with White Spirit to remove oily residues before priming.
Dispose of solvent soaked cloths in a lidded metal container.
Seal well all end grains.
Wet abrade where possible – it is more effective and creation of dry dust particles is reduced.
Use good quality exterior fillers outside.
Avoid painting in temperatures below 5° C or when rain is expected during application or drying periods.
Tightly re-seal lids and shake tin to form seal.
Preparation
All surfaces must be sound, clean and free from anything that will interfere with the adhesion of the material to be applied.
Prior to painting the moisture content should not exceed 18%.
Rub down new timber with fine abrasive paper to obtain a smooth finish. Lightly round off sharp edges to a 3mm radius. Dust off.
Remove all areas of detective paint coatings back to bare wood by scraping and /or use hot air paint stripper or proprietary paint remover as per manufacturer’s instructions.
Rub down exposed timber with abrasive paper to obtain a smooth finish.
Feather off edges. Dust off.
Remove excess resin from any live knots by use of a hot air paint stripper.
Wipe immediately with methylated spirit to remove residue.
Apply two coats of fresh shellac knotting to all exposed knots and resinous areas of timber.
To all non-durable, non-preservative treated bare softwood timber, brush apply a proprietary timber preservative to all exposed surfaces and end grains, in accordance with the manufacturer’s instructions.
Allow solvent to dry thoroughly before over-coating.
Scrub and swab oily hardwood surfaces with white spirit, frequently changing the face of cloths.
Allow solvent to evaporate before priming.
Rake out any defective putty fillets and cut out all rotted timber.
Replace rotted timber with new sound timber, pre-treated with suitable timber preservative, as already described.
Prime all bare timber. Including exposed putty rebates, with appropriate Albany Primer.
Wash all remaining areas of sound paintwork with a mild detergent solution to remove dirt or grease deposits.
Wet abrade surfaces with waterproof abrasive paper to form a key. Rinse thoroughly with clean water to remove all residues. Allow to dry.
Ensure all pin, nail and screw heads are sunk well below the surface and make good all surface imperfections with a suitable wood filler.
Allow filler to dry. Rub down smooth and level to existing surface. Dust off.
Remake putty fillets with linseed oil putty and allow putty to form a hard skin before painting.
Allow overnight drying between coats in the case of solvent borne paints. Lightly denib and dust off before over-coating.
An extra of Undercoat may be required to help fill surfaces on new work and also on re-paints where a contrast colour is involved.
Some strong colours may require extra coats.
