Masonry Paint - Lime Wash and Silicate Paints

Conventional masonry paints are similar to conventional emulsions in the fact that they are based on petro-chemicals, give off VOCs and also are not designed to be breathable.

Lime Wash and Silicate Paints are designed to be breathable and so are necessary on older buildings that breathe (so anything pre 1920s and timber framed buildings). However they do need to be applied to the masonry not over existing non-breathing paint, so this is a key area to bear in mind.*

Lime wash is the cheapest option and it provides a great deep matt finish, however it does need approx. 4 coats as it is quite thin. Lime wash is also naturally alkaline and so will gradually be removed by rain (which is naturally mildly acidic). In exposed areas this will mean having to re-paint every 4 - 5 years. However in settled spots this will decrease. Lime wash can be tinted into a range of colours using mineral pigments.

Silicate paints are much harder wearing and even though they need 3 coats (one primer and 2 top coats), once they are on the paint will last around 15-20 years. Consequently the paint is more expensive, but in the long run it is very economical as it removes the need for painting. Silicate paints are available in a range of pre-mixed colours from earthBorn or you can make your own by using the pigments.

*Note, that it is possible to paint over existing paint, but it entails 5 coats inc. two etching coats, a primer and then top coats.