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 on 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 masonry paint, eventually causing it to lift. This will happen faster during the winter because the water will expand as it freezes and lift larger areas of paint. Moisture is the single most common cause of peeling masonry 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.
How to Fix Peeling Masonry Paint
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. 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 then you’ll create even more problems.
It works by penetrating the masonry, and seeping behind the existing paint. This sticks the edges of the paint down, meaning it is less likely to peel again in the future. It also solidifies any chalky masonry, creating the perfect base.
My favourite masonry filler is Toupret Murex (now called “Rock Solid Filler”) because it dries rock hard. Some masonry fillers remain porous, which means they can hold onto moisture and potentially cause the paint to fail further down the line. Murex doesn’t do this, so repairs are more likely to last.
Toupret Murex is easy to use and great to mould as you need to. It doesn’t slump either and you can use it on holes of any depth. Just be conscious that it’s difficult to sand once it has cured, so try not to fill proud.
The Best Paint to Use to Avoid Peeling Masonry Paint in Future
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.
There are two different masonry paint products I can wholeheartedly recommend. One is probably the best standard masonry paint for this type of job. The other is more expensive, but is probably the best masonry paint on the market. Using either of them means there is less chance of your masonry paint peeling in future.
This is the trade option, but unlike most other trade masonry paints on the market, it is silicone-based. This means the paint film is very breathable and self-cleaning. Wethertex also sticks hard and fast to just about anything and is exceptionally durable once dry. It also remains flexible.
Being a trade product, you’ll also find Wethertex reasonably priced.
Emperor Paint Masonry Paint
This is another silicone-based masonry paint, but it is manufactured to a higher quality than any trade product. It’s very breathable, hydrophobic, self-cleaning, and the paint on any surface is likely to last around 25 years. This is because of the quality of resins within the paint. It is also proven to help with heat retention in your home.
Emperor Paint is expensive though. If you do buy this product, you can use code ‘forum5’ for a discount.
A recent Job we Completed
I thought I’d share details of a job we completed recently and explain how we fixed the peeling masonry paint.
This house was only painted previously a year ago. The homeowner had cleaned everything properly before she painted. She’d also used proper trade products to achieve her desired finish. She was very happy with the way it looked when it was completed, but the paint started peeling within months.
It took two of us a full day to carry out the prep. We scraped all the peeling masonry paint from the render, applied anti-fungal wash, allowed it to dry, then coated Zinsser Peel Stop over the whole lot.
We didn’t need to do any filling because apart from the failing paint, the walls were in good nick. Peel Stop was enough to hide the edges of the failed paint. We then applied two coats of Wethertex AP77 (which is a fantastic paint).
The house looks like new now, and I gave the client a 2-year guarantee. However, I’m confident that the paint will last a lot longer.
Tools you Need to Fix Peeling Masonry Paint
Very quickly, I thought I’d mention the tools you will need to fix flaky masonry paint. I’ll link to the products where I can make things nice and easy.
Access equipment – There’s no point in me linking for this one. If your flaky masonry paint is high up, you will need a ladder, scaffolding, or a cherry picker to reach it. You can buy any of these items, but unless you’re going to use it on a regular basis, you’re probably better hiring it. Just have a quick Google search and phone your local hire shop. They’ll even drop it off and pick it up for you.
Scraper – This is an obvious one, but you will need a scraper to remove flaking masonry paint. Click here to see online prices.
Paint roller – Any long-pile 9-inch roller on a pole is perfect for applying both Zinsser Peel Stop and masonry paint. The best roller for this type of job is the Purdy Colossus. You’ll find it holds and distributes loads of material, which makes working at hight a lot easier because you don’t need to load it every 2 seconds. It’ll also coat the surface of rough textured masonry. Click here to see online prices.
Paintbrush – There are a couple of different paintbrushes I could recommend for applying masonry paint. Stay away from those big floppy “masonry brushes” in DIY shops because they’re very difficult to use. If you want a cheap brush that’s up to the task, then go for Hamilton Prestige. Click here for online prices.
If you want the best brush available for applying masonry paint, and you want something you can wash out and carry on using it for years to come, then go for the Purdy Monarch Elite XL. You pay more, but it’s a brilliant brush. Click here to see online prices.
Can I paint over peeling exterior paint?
The issue with painting over peeling paint is that no matter what paint system you use, if the existing paint carries on peeling, then both will fail. We recommend removing as much of the peeling paint as possible, applying a coat of Zinsser Peel Stop, and then repainting with a breathable product.
Can I paint over old masonry paint?
Providing your existing paint is sound, then painting over it is not an issue. Just ensure it’s clean before you start painting and use a fungicidal wash if required. Prepping exterior walls is important.
What is the lifespan of masonry paint?
Cheap masonry paint doesn’t tend to last very long at all. Even some of the ones that claim to have a “15-year lifespan” can start to lose their colour, go mouldy, or start to peel. We recommend using Emperor Paints if budget allows, or Wethertex if you need a cheaper alternative.
I hope that helps. Fixing peeling masonry paint is nothing complicated. You just need to understand what’s causing the problem, get your preparation right, then use the correct products to avoid issues in the future.
The best advice I can give you is use breathable paint products to avoid trapping moisture.
How to Fix Peeling Masonry Paint – by Mike Gregory