Wood Coatings - Wacker Chemie AG

Wood Coatings

Timber has many advantages as a material for building and construction: it is a renewable resource, easy to process and has that pleasantly natural look and feel. But it is very susceptible to weathering when used outdoors. Especially water poses a major threat. Absorbing and releasing water causes wood to swell and shrink, leading to massive damage to the surface. Water also dramatically accelerates the rotting process.

Conventional wood protection such as water-repellent impregnations and coatings unfortunately wears off over time.

For this reason, WACKER has developed SILRES®WH for wood hydrophobation – a functional, flexible silicone resin, specifically designed for wood. It provides reliable long-term wood protection by keeping the amount of absorbed water very low. Even after years of weathering, the renowned breathability and beading effect of SILRES® provides reliable protection.

Water absorption is significantly lower in wood treated with SILRES® WH than it is in untreated wood – and remains extremely low, even after 4,000 hours of QUV weathering.


How do I use SILRES® WH?
SILRES® WH is usually diluted 1:4 to 1:9 with water for direct application to wood. SILRES® WH can also be added undiluted to waterborne stains in concentrations of up to three percent.

Does SILRES® WH allow for reduced use of biocides?
Yes. Using SILRES® WH provides long-lasting protection from water and from the damage it causes. That allows for reduced use of biocides, especially fungicides. In the case of many biocides, it eliminates their use entirely.

Can wood be painted after it has been impregnated with SILRES® WH?
Wood treated with SILRES® WH can, in principle, be painted if some weathering of the impregnated substrate is allowed first. However, one thing needs to be remembered: smooth wooden surfaces will absorb only some of the silicone – the rest remains on the surface. As a result, and especially in the case of highly concentrated wood preservatives, paint adhesion may be restricted and leveling impaired. For this reason, SILRES® WH should not be employed as a primer.

Will beading be visible right away?
Yes, but the beading effect becomes best visible after the treated surface has been exposed to the elements for a while. With SILRES® WH, however, beading will then be visible for an unusually long time.

Does SILRES® WH keep wood from graying?
No. SILRES® WH does not prevent graying, because this is caused by UV radiation, and silicones are transparent to UV radiation. SILRES® WH does, however, help make graying uniform.


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