Which paint should I use on a mudbrick?
The good news is, this is a simple answer.
From our 40+ years of experience, we’ve found that our Colourcoat is the most appropriate paint to go directly over mudbricks. We have other products that are suitable for use on Mudbricks, such as Grimes & Sons Render Additive, Clay Fine Render, Silicone Water Repellent, Mudbrick Water Repellent, & Clear Dustproofer.
The next question you may have, is why?
Colourcoat is a vapour permeable paint. This is critically important. Without that, moisture becomes trapped within the mudbrick walls, especially those that are interior/exterior walls. Mudbricks work by passively absorbing atmospheric moisture and heat, and holding them until there’s a significant difference between one side and the other. This is why during particularly hot summer days, mudbricks are often noticeably cooler than houses built out of more common materials. Acrylic paints form a solid film that prevents any vapour transfer and significantly interferes with mudbrick thermal regulation.
So what does this mean?
What will often happen is that mudbrick walls with acrylic paints on them develop blisters. The moisture tries to escape, but given the coating, it builds up. Over time, little pockets will begin to delaminate from the mudbrick wall, and oftentimes, these blisters can measure in metres. Mudbrick walls with acrylic paint need to have it at the very least partially removed, but ideally, mostly removed. The simple way to tell if it needs to be removed is by sound. With a knuckle, handle of a hammer, or any sort of thing like that, tap along the wall. If you hear a hollow sound, it means the coating there needs to be removed. It always pays to remove as much of it as possible at the time to reduce the incidence of it happening again. If the walls are still in a good condition despite the acrylic paint, we recommend “breaking the seal” by going over the wall with a wire brush to allow at least some vapour transfer. Once this is done, priming the wall with Render Additive and water and then coating with Colourcoat to finish the wall is required.
How do I prevent this?
Another simple answer. Whether doing the works yourself (see here) or hiring tradespeople, make sure you ask for Colourcoat. Never settle for inferior products when it comes to the integrity of your Mudbrick home.
