TRADA tackles weathering

TRADA Technology has published a new Wood Information Sheet, Specifying timber exposed to weathering to explain the causes of weathering and the impact it may have on timber's performance.

Weathering can be described as the chemical and physical changes that occur when timber is exposed to the weather.. Weathering is a surface phenomenon and usually occurs within the first 2.5mm of the surface and should not be regarded as a problem, but rather a natural process.

Weathering can develop through exposure of wood to rain, snow and ice, UV light and wind. The type and rate of weathering will vary with geographical location and level of exposure.

Uncoated timbers exposed to the weather will over time develop an attractive silver/grey colour, although the timescales for this colour change are hard to predict - much will depend on the elevation, extent of exposure and the season in which the timber was installed.

The rate of colour change, too, will vary between species. Hardwoods tend to take longer than softwoods, particularly if it is a very dark timber to begin with, and variation within the same species is not uncommon.

Specifying timber exposed to weathering goes on to outline how to prevent weathering by using paints, stains or varnishes, but explains the pros and cons of each.