Siberian Larch, Western Red Cedar & Treated Redwood are sustainable options, widely used for façades in schools, community hubs, sports and leisure centres and in retail.
Natural timber finishes for new build projects are still very popular with architects who want a traditional and ‘honest’ finish that will often blend in with the environment and change over time.
A2O approach the design of our timber rainscreens in the same way as a metal, stone or terracotta project. The timber finish is supported with an adjustable aluminium grid to achieve line/level and accommodate the required insulation.
Special consideration is given to preventing warping; accommodating natural movement; specification of fixings and the potential of staining from natural tannins within the wood. Many of our projects now include fire treatment of the timber elements to prevent surface spread of flame.
Siberian Larch is a cost effective but also naturally durable option that requires no preservative treatment. It starts as a rich golden colour but over time will weather to a beautiful grey. Larch is susceptible to significant movement/shrinkage and this needs to be factored into the design and fixing.
Western Red Cedar is a very stable and beautiful rainscreen cladding solution. It is naturally durable and requires no preservative treatment. Left untreated it will change from a pinkish, sandy colour to a silver grey. It is very popular with architects.
Redwood is not a naturally durable species and requires a preservative treatment in order to be used as an external cladding finish. Once pressure treated, it will hold its colour for a prolonged period and can achieve a 30-year warranty against rot and fungal decay.
We believe that paint should always be applied to timber off-site. The natural shrinkage in timber means that unfinished edges can appear over time. A2O work with key supplier Vincent Timber to install their Cape Cod pre-painted timber cladding.
Fire treatment of timber cladding is becoming a requirement on most new build projects. A2O work with building control and architects to ensure that the correct product and specification is applied. These products typically achieve a B s1 d0 rating from suppliers including HR Prof, Burnblock and Sentrin FRX.
Preservative treatments can be applied to timber in a high pressure cylinder, offering a formal warranty for the timber. These treatments can contain either micronized copper or other ingredients with minimal environmental impact. Unlike some lacquered treatments, these treatments penetrate the timber and therefore do not peel off over time.
BRUNNEA TREATMENT
A2O carry out many installations with NORclad’s Brunnea-treated redwood and larch. NORclad Brunnea treatment is a high pressure, water-based preservative treatment, impregnated into the timber cladding. It provides long term protection against insects, rot and fungal decay. The “Brunnea” pigment is a UV inhibitor, which holds colour for longer and reduces the rate of weathering.
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