Heritage & Breathable Coatings

Pre-1919 buildings were constructed with lime mortar and solid walls that rely on vapour permeability to manage moisture. Standard modern acrylic and vinyl paints form an impermeable film that traps moisture within the wall structure, leading to blown plaster, salt crystallisation damage, timber decay, and accelerated paint failure. Breathable coatings such as limewash, casein distemper, and Keim mineral silicate allow moisture to pass through freely.

Keim Granital is a mineral silicate paint developed in Bavaria in 1878. The liquid potassium silicate binder penetrates the masonry substrate and forms a permanent covalent chemical bond through a process called silicification. The paint literally becomes part of the stone. This creates an extraordinarily UV-resistant, non-flaking finish that has been documented lasting over a century on European buildings.

Repainting a listed building with like-for-like breathable coatings typically does not require listed building consent, as it constitutes routine maintenance. However, changing from one coating type to another, altering colours significantly, or applying modern paints where breathable finishes were originally used may require consent. We advise consulting your local conservation officer before work begins.

Limewash is applied in multiple thin coats rather than one or two thick coats. A typical limewash scheme requires three to five coats applied while the previous coat is still slightly damp. Each coat builds translucent depth and character. The total process takes several days as each coat must be misted with water during curing to prevent the lime from drying too quickly and powdering.