On some properties — particularly older or previously restored buildings — we occasionally find mineral-based or cementitious coatings beneath the outer layer of paint. These coatings are completely different from modern paints. They’re designed to bond permanently to the brickwork, providing a long-lasting, breathable protective finish that allows moisture to escape while shielding the surface from weathering.
Because of how they’re made, these coatings cannot be removed with steam or chemicals. The only way to take them off would be through aggressive abrasive methods, which would cause severe and permanent damage to the brickwork — literally grinding away the surface of the bricks. That’s why full removal is never recommended. These coatings were applied as a durable, breathable layer, and in many cases, they’re still doing their job decades later.
The image below shows a clear example of this. The top half of the wall still has a modern pink non-breathable coating, while the bottom half has been stripped back to reveal the original mineral-based cementitious coating beneath. This older coating is breathable and protective, but it cannot be removed without damaging the bricks — so it’s best left in place.
The problem arises when a modern, non-breathable paint has been applied over the top. Non-breathable coatings trap moisture within the breathable mineral layer and the brick beneath. As that trapped moisture freezes and expands, it causes cracking, flaking, and surface damage — the same kind of deterioration you’d see when non-breathable paint is applied directly to brickwork.
When the outer coating is removed, any cracked or weakened sections of the underlying mineral-based layer can be knocked loose, just like damaged pointing or spalled brick. The result is often a patchy mineral coating that can’t be restored to bare brick without causing further harm to the surface.
For more on this topic, see our related guide on non-breathable paint damage.
In these cases, the best solution is to repaint using a compatible breathable mineral-based coating, restoring a consistent appearance while maintaining full breathability. Another option is to apply a breathable render system over the existing coating for a uniform finish. However, complete removal of cementitious coatings is never advised, as doing so would cause unnecessary and irreversible damage to the brickwork.