There are 3 main types of finish which can be used on most exterior timber
- Clear finishing
Some time spent considering options now, can save much time and effort in the future.
- Preserves the natural colour and grain pattern of the timber.However it will not cover
any existing discolouration or
damage, is not recommended
for rough sawn timber and will
require regular maintenance
Clear coating is usually
recommended only for new
timber or timber otherwise in
good condition. The life of a
clear finish can be greatly
enhanced by the application
of an exterior stain before clear coating.
- Solid cover painting, whether by acrylic or enamel, is generally recommended for all timber surfaces, new or old. A high quality 100% acrylic will provide the ultimate in exterior durability and ease of maintenance. It will add colour and life to almost any surface whilst allowing the natural texture of the surface to show through. Other specialized Outside Finishes such as Decking Finish and Garden Furniture Finish offer similar advantages but are formulated especially for the surface designated.
A coat of Wood Preservative, if applied BEFORE an oil based stain, paint or clear, will give greatly enhanced water repellency. Do not use if using a water based topcoat.
Handy Hint: It is strongly recommended that if at all
possible new timber should receive at least one
coat of the desired finish BEFORE CONSTRUCTION.
This will ensure all surfaces are protected. The final
coat can be applied after construction is complete
Previously Painted Surfaces - Test the Surface.
Ensure that the surface is in a sound condition by
testing at random its ability to withstand recoating
without lifting or peeling of the old paint system.
Cut a small "x" through the topcoat, and place a piece of tape over the cut. Peel off the tape. If the tape pulls the paint away, the surface is unsound.
Test different areas before deciding whether or not the surface coating should be removed. Unsound surfaces should be stripped before recoating to achieve the best results.
Remove any loose or flaking paint with a scraper or wire brush and hot air gun if necessary, then sand the surface smooth and remove all dust before recoating. If any gloss remains on the old finish the surface must be thoroughly sanded to remove all gloss to assist the adhesion of subsequent coats. Remove all dust.
Handy Hint: Galvanised nails should be used to avoid rust staining on exterior surfaces. Otherwise punch nails below the surface and then fill these holes with a linseed oil putty or an exterior grade putty.
Allow 48 hours drying time for linseed oil putties before finishing.
Paint drying times are calculated for 25C, 50% relative humidity and any variation from this will affect drying times. Most paints cease to dry below
10C It is therefore essential that you do not paint if the surface temperature is likely to fall below 10C during the application or drying period.
Temperatures over 35C are likely to cause too rapid drying and result in blistering especially in water based paints. For this reason it is advisable not to paint if the temperature is above 35C.
Most water based paints may be applied to damp surfaces and it is recommended on very hot days, especially with very absorbent surfaces, to dampen the surface before painting. Care should be taken as too much water will obviously result in a very thin coating. Turps or oil based paints MUST NOT be applied to damp surfaces.
Consideration should be given in cooler locations or in cooler months to the onset of dew. Until paints are properly cured, they are very susceptible to damage by dew. At the very least the gloss level may be reduced, at worst they may be washed off. If in doubt wait for a warm sunny day!