Linseed Oil Paint – An Unlikely Hero in Preservation

Interested in why linseed oil paint was used for the finish of the window sash in our Fall 2023 Preservation Update? Linseed oil paint has been used for centuries quite simply because it works so well at protecting the substrate and creating good aesthetic appearance. Historically it would have contained lead for anti-mold properties, but this harmful ingredient has been replaced with a combination of zinc and titanium white which works just as well.

The decay of historic timber started with the introduction of synthetic petrochemical paints and wood treatments. Even though many countries retained some usage of linseed oil paint, vast amounts of knowledge were lost; resulting in the product dying out.

Linseed oil paint was traditionally found anywhere flax was grown, generally the shorter variety was used. It is derived from pressing the seeds of diversely useful flax plant (Linnum ussitatisimum). When used on its own, raw or boiled, it is not suitable for use outdoors due to its lack of protection against UV breakdown. Those before us discovered that mixing earth into the oil makes the wood treatment longer lasting and more durable. If used correctly, there is no increased risk of mold growth compared to modern paint.

Using historically accurate ingredients and methods keeps the paint historically correct. There is no recreation or imitation like there would be with modern paint. Of importance, linseed oil paint leaves a fraction of the carbon footprint of man-made materials.

[This article was first published in our Fall 2023 Newsletter]