Like a blister in the sun...
posted: 14/Sep/2015
With the mercury slowly rising to warming temperatures and the Queensland sun back out in full force as winter winds up, you may begin to notice (or have noticed) blistering in the film of paint applied to outdoor timber or timber structures.
The common train of thought is that paint blistering is caused by moisture creeping behind the paint film – either via small holes in the film, or where cracks in the paint job have allowed water to enter behind the film. Sometimes if you prick one of these blisters, water will run out.
However, temperature-related blisters can be caused where hot sunlight heats up freshly painted timber and the rapid rise in temperature causes vapours to expand and paint to blister. This kind of blistering will occur between a few hours to a few days after the paint application. These kind of blisters can be between paint film, as with moisture blisters, or between film and wood. High resin-content timbers (Kwila, Merbau etc.) wherein the volatiles from this resin can also heat up and release vapour or gas can be more susceptible to this kind of blistering.
The moral of this story: Follow paint manufacturer’s recommendations, and stick to light coloured timbers and finishes outdoors!
Previous Articles
Do you know your timber truss history?
If you've noticed off colour seeping through paint on pine cladding you could have "knot bleed".
Going to buy some paint? Read before you hit the hardware store.