Friend and colleague Tina Reichenbach of Richbrook Conservation offers the following advice about choosing the right paint for historic exteriors:
Far more important than paint color is the type of paint used for painting exterior woodwork, especially for the preservation of old or heritage properties. Evidence from the past 50 years or more since the introduction of synthetic resin based paint (latexes and alkyds) has shown just how damaging they are when used for exterior wood. Regardless of whether using a ‘luxury’ brand or not. Such paints are based on byproducts of the petrochemical industry and act by forming a barrier film on the surface of the wood which traps moisture and accelerates wood rot as well as interior moisture isses. Add to that, the typical life cycle, before the paint manufacturers recommend re-painting, is only 5 years, so the layers accumulate on surfaces and exacerbate the situation. It is akin to adding a plastic skin over a material which needs to breathe, so the vapor dynamics in the building system are severely disrupted, with damaging consequences. Making matters worse, the commercial paint industry is one of the largest contributors to plastic pollution and microplastic contamination.
If your readers or your clients are interested, there are several manufacturers now of traditional linseed oil based house paint, which has better material and mechanical compatibility with wood used on the exterior of a building. The re-painting cycle is much longer, closer to 15 to 20 years which makes it economically more sensible. Non-toxic, zero VOC, etc etc. And it looks dynamite! The only potential drawback is the learning curve in application, as it requires a slightly different discipline to properly use and clean up, and associated labor costs and finding qualified contractors. Still, I would encourage you as much as possible to steer your clients away from using synthetic resin based paints and to explore traditional options. Even for interiors, there are a lot of less toxic and more aesthetically appealing alternative paint materials to consider.
Wise words!
