Finnforest UK

ThermoWood^® is a durable product that will last for many years without applying surface treatments.  The natural effect of weathering and exposure to sunlight can however cause fading, surface cracking and the potential for algae growth.

Pigmented translucent stain gives protection against UV-light (i.e. greying of the surface) and retains the natural ThermoWood^® appearance.  The most commonly used are translucent stains with brown pigment close to the original ThermoWood^® colour.  The finish is usually slightly darker than ThermoWood^® natural colour.

Choose wood finish recommended for softwoods and for exterior use.  Use either translucent wood stains or opaque wood stains.

Exterior wood stains perform generally better on textured sawn surfaces than on smoothly planed ones.

Different treatments will have different maintenance intervals.  The more pigment used the longer the maintenance free period.  See paint manufacturer instructions.

It is recommended to apply one coat of finish before installation and apply additional coats once the boards are in situ.  Sealing of end grain is very important.  It will reduce the potential for any moisture ingress and possible end staining around the end grain.

The finish should be applied on ThermoWood^® in accordance with the recommendations of the paint manufacturer, with strict attention given to proper coverage instructions, temperature and weather conditions at the time of painting and other specific requirements.  Surface must be clean and dry when treated.

examples of paint manufacturers' recommendations

6.1 maintenance

The environment and climate have a crucial impact on the service life of surface treatment.  UV-light and moisture are the major factors affecting surface treatments.  This could mean south facing elevations needing more regular maintenance than those facing north.  In addition buildings exposed to sea air may require more maintenance than those inland due to the abrasive factor of the wind blowing in from the sea.

To ensure maximum performance of coatings the surfaces should be cleaned and checked annually.  If defects occur it is usually a sign of a structural weakness which should be repaired immediately.  Mechanical damage requires instant repair.

Annual inspection is advisable in order to avoid possible serious damages.
Always refer to the paint manufacturer's specific instructions of maintenance, if available.

maintenance check list for ThermoWood^® cladding

A. Fixings of cladding boards and trims
Fix loosen cladding boards and trims.  Replace any damaged boards.

B. Dirt on the surface
Wash down according to paint manufacturer instructions to remove contamination from weathering and any loose particles.

C. Coating and need for repaint
Loose paint material should be removed by sanding or scraping.  Brush down to remove dust from the surface.  Surface treatment with one or more coats.  Use the same translucent wood stain or opaque wood stain as used before.
Always follow paint manufacturer instructions.

D. Rain damage
Clean any accumulation of leaves and trash from the gutters so that the water flows freely through them.  Repair any leaks where water can get behind the cladding boards and cause deterioration.  Make sure that water does not stand on horizontal surfaces (chamfering of horizontal surfaces and bottom edges).

E. Flashings
Any flashing that does not direct water away from the cladding boards, or allows water to penetrate into the wall, must be corrected.  Improperly installed flashing may cause leakage.