FEATURE
LOCATION AND CLIMATE
Samples tested and exposed in Cape Town ( Western Cape ) degraded much faster than those tested and exposed in the more tropical Tzaneen area ( Limpopo province ). Treatment selection therefore needs to consider environmental factors such as humidity , wind , UV index , rainfall , and wet seasons .
Application Certain samples that weathered very well on exposure racks did not fare as well during walkway tests , when subjected to everyday use and wear and tear . Factors that play a role here are physical abrasion ( such as foot traffic on a walkway or deck ), orientation ( whether the surface is flat or vertical , in the sun or shade ) and construction ( such as exposed areas at joints , or moist areas under decks ).
Wood quality During testing , our higher-quality or select-grade lumber was identified as least likely to exhibit surface checking , splitting , or cupping – all features that increase the risk of water ingress , which has a damaging effect on timber . Exposure to the elements , as well as drying and treating the wood , can further develop these defects , especially in lower-quality timber .
Type and density of wood Not all treatments can be universally applied on all species and variations of wood . The Merensky exposure tests revealed that some treatments formed a good-looking surface layer after treatment but did not penetrate the wood surface layer – especially on higher-density hardwoods . These may therefore start to flake quickly when treatments dry out or are exposed to high-wear conditions .
Maintenance requirements Film-forming surface treatments such as varnishes were shown to start flaking or peeling when not maintained for prolonged periods and , in most cases , a complete removal of the treatment was required to remedy this . Most manufacturers recommend that a fresh coat be applied , either within a certain timeframe ( for example , within 24 months ), or when the surface appears dry .
Penetrating treatments such as oil-based products are similar , but with one key difference : they are far more forgiving when not timeously maintained , and a fresh coat can usually be applied without the need for any remedial action . In such cases , though , the wood ’ s appearance might have changed , depending on how long the surface remained unmaintained .
Certain treatments were shown to provide very good alternatives to regular oil or varnish products , with regard to both penetration and maintenance requirements . Significant advancements were demonstrated with penetrating sealers and water-based treatments .
Treatment selection therefore needs to consider environmental factors such as humidity , wind , UV index , rainfall , and wet seasons .
// AUGUST / SEPTEMBER 2021 23