Many products are marketed as ‘breathable’, and whilst all paints are breathable to a degree, what’s important is how breathable. When looking for a breathable paint, there are two common ways to check how breathable it is.
The first is the SD (Steam Diffusion) value, which is a German method for measuring breathability. It is widely accepted that for a paint to be classed as breathable it should have an SD value of 1 or lower; the lower the value the more breathable the paint. Earthborn Claypaint has an SD value of just 0.02m.
The other method used to measure breathability is the moisture vapour transmission rate (MVTR). It measures the amount of water vapour (in grams) able to pass through the paint surface over a 24 hour period. The higher the figure, the more water vapour that can pass through, and therefore the more breathable the paint. Earthborn Claypaint has a figure of 1115g/m2/24h, compared with a typical emulsion paint which usually measures between 400-500g/m2/24h.