Resin Bleed - A Major Issue for Exterior Timbers

For this reason, many manufacturers of natural timber weatherboards and cladding specify that only lighter colours can be used on their products. This is to reduce the heat build up in the wood, and reduce the chance of resin bleed, and other resin related stains.

This fact is recognised in Australian and New Zealand building standards, and recommendations:

• The Australian/New Zealand Standard, AS/NZS 2311:2009 Guide to the Painting of Buildings in section 2.2.5(i) states that "Dark Colours in exterior situations increase the absorption of heat and this may have a deleterious effect on the paint coatings and substrate materials".

• BRANZ, New Zealand’s building advice organisation published a "Good practice guide" to "Exterior Coatings" and in section 4.2.2 recommends that "Colours are selected carefully to suit and minimise stress on the substrate".

Some preservative treatments such as Light Organic Solvent Preservative (LOSP) can also contribute to the mobilisation of resin in the timber. It is important to ensure that the solvent has completely flashed off before coating and despatch.

Abodo’s Vulcan Cladding is an excellent choice to mitigate resin bleed. During the thermal modification process most of the natural resins are burnt from the wood, meaning there is less resin to bleed out. Using Vulcan Cladding allows homeowners the choice of a larger range of colours, and combined with Resene Coolcolor paints, even darker tones can be used.