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Q&A: Anti-Condensation and Damp Paint

Having damp or even worse, penetrating damp in your property is likely going to cost you thousands of pounds to fix.

Fortunately, taking preventative measures is usually enough to stop damp entirely. One of the best preventative measures is using an anti-condensation paint.

But what is an anti-condensation paint? How does it prevent damp? Can you use it after the damage has already been done? We’ve taken some frequently asked questions along with reader-submitted specific questions and answered them all below.

By time you’re done reading this article you should be an expert on anti-condensation paint! With that being said, let the learning commence…

The Basics

What is anti-condensation paint?

I’m not going to be receiving any gold stars for this one but obviously it’s paint that prevents condensation build up.

How does anti-condensation paint work?

Anti-condensation paint works wonders when it comes to insulating your walls and ceilings. When the surface temperature of your walls and ceilings is higher, moisture in the air doesn’t condense when coming into contact with them and thus condensation isn’t able to form.

Basically, the added insulation stops condensation.

Does it look as good as other paints?

You can absolutely get a professional finish using anti-condensation paints. Top brands such as Ronseal, Dulux and Coo-Var all have variations of paints with the Dulux Easycare Bathroom in particular offering multiple different colours.

The Specifics

My bathroom ceiling has peeled several times. I’ve used anti-condensation paint but it still peels. The ceiling is very low to the shower so assuming it takes quite a bit of condensation but is there a product that could withstand it?

You need to get some quality paint such as Coo-Vat, but most importantly you need to sand it back with a dustless sander for optimum adhesion rather than just keep adding more and more layers of paint. If that doesn’t work, you’ll need to look into properly venting your bathroom or fixing the leak that is causing the problem.

I finished painting my living room recently and a weird splash like stain appeared on the wall 2 days later. Have you seen the same/are aware of possible causes and remedies?

Was there any filler used in that area? I had a job like this in Clifton in Bristol a few months ago. I was supplied with Polycell multipurpose filler then used Farrow & Ball to paint the hallways and staircase. I came back the next day and all the filler had burnt through. It turns out the filler contained Portland Cement and needed Alkyd paint.

We ended up getting an oil based undercoat and going around and touched up all the filler again with the undercoat and applied a full coat on the walls. That may be an option for you to just use an oil based undercoat then topcoat the wall.

Have you ever painted an air con unit and is there any reason not to?

I’ve never painted one because they hold moisture and can be extremely cold. If you were to paint it there’s a good chance that condensation will form on it and ruin the paint job. In my opinion, it’s probably not worth the time and effort, especially if in the end if it turns out you need to remove the paint anyway.

Can you just paint over surface mould after cleaning?

Theoretically yes. After cleaning and rubbing down the area, use a damp seal or stain block before applying anti-condensation paint. The issue is that if poor ventilation is the cause, it might not totally fix it. You’ll probably need to fix your ventilation to stop the mould growth.

Our house is 20 years old and we are decorating our bedroom. We’ve found that there’s this chalky stuff coming off the walls and it’s getting worse with time. Do you know what this could be? The wall is an interior to an outside wall.

My initial feeling from your description is that the ‘chalky’ residue is probably salt (efflorescence) that has been brought to the surface of the plaster by the condensation in the air. I’ve been seeing this more and more with new builds and it sounds like you might have this issue too.

You’ll need to treat the wall with a salt neutraliser (Rempro are decent). Follow the instructions on the container for how to use it. Be warned though, it’s not a pleasant smell!

What paint would you recommend for a really steamy shower room. My mate recommended using Sandtex smooth masonry paint?

My advice would be to ignore your mate! Get yourself something like Zinsser Perma-White water-based satin if it’s really steamy. It has a soft sheen finish but it sounds like you have more important things to worry about than the sheen level.

My wall has 3 big wet circles on it. It has been tanked, had Stain Block, Zinnser and even oil based gloss on it to stop these rings showing through…it looks like damp. It’s an internal wall, no pipework anywhere near it and no chimney breast. Just a single brick wall with no cavity. Any ideas?

To be honest the products you’ve mentioned would’ve solved the issue if it was damp (and you’re right, it sounds like damp). The only thing you can really do at this point is replace the drywall/plaster. I’m afraid there’s nothing any paint product will do to help that.

What’s your thoughts on Biotech anti-damp paint?

It’s a good paint, has good coverage and is really nice to apply. At £100 a tin I wouldn’t use it unless it was supplied by the customer. Coo-Var does the same job at much less cost so I would go with that personally.