How to Fix Peeling Masonry Paint
By Mike Gregory
I’ve been a decorator for the best part of two decades and in that time I’ve worked on just about every type of job. Exterior paint jobs are one of my favourites, but peeling masonry paint can be a right pain. I thought I’d take the time to explain how to fix peeling masonry paint. I really hope this blog helps you out.
Why Does Paint Flake off Render and other Masonry Surfaces?
There can be a few reasons, but 9 times out of 10 times it’s down to one, or both of the following issues. Funnily enough, the problem is easily avoided by using paint which is better suited.
This is an obvious one, but if there is trapped moisture in the render or stonework, it will cause problems. The water tries to escape the render, only to find itself trapped underneath the paint, eventually causing it to lift. This will happen faster in winter because the water will expand as it freezes and lift larger areas of paint.
A lot of cement contains limestone and cement is a key ingredient of render. This is an issue because lime is slightly alkali and needs to breath. A lot of modern masonry paints such as Dulux Weathershield simply smother the render, resulting in the paint failing over time.
The first thing you must do is remove as much of the existing paint as possible. You can either use a scraper and some elbow grease, or go at it with a power washer. Just be careful not to damage anything else in the process and be safety conscious when working at hight. If you’re using the power washing, give your render a couple of days to dry off before carrying out the next step.
The next thing you need to do is stabilise the surface and stick the edges of the existing paint to prevent them from lifting again. For that, I use a product called Zinsser Peel Stop. There are other stabilising solutions on the market, but Peel Stop is perfect for what you need here. It is a water-based product and as the name suggests, it prevents paint from peeling. Just make sure you adhere to the 2-hour drying time (longer if you can). If you rush things you’ll create even more problems.
I normally do my filling at this stage. The Peel Stop helps mask the edges of the remaining paint, but you can also fill round if you feel it’s going to show once painted. Other than that, it’s just deeper holes. My favourite masonry filler is Toupret Murex because it dries rock hard and lasts for years.
The finish Paint
It is essential you use a breathable paint product to finish. By using something that allows your render or stonework to breathe, you avoid failure which may otherwise occur due to both moisture or lime. For me, that product is Wethertex AP77 smooth masonry paint.
Wethertex is a water-based product with silicone technology. As well as allowing a surface to breathe, it’s also water repellent and self-cleaning. Wethertex also sticks hard and fast to just about anything, then dries to be exceptionally durable. Click here for more info on Wethertex.