Condensation in your home can be an absolute nightmare. It can lead to problems like mould, a bad smell, and breathing difficulties. But what causes it, and what can you do to stop it?
I’m going to explain how to stop condensation on walls. I’ll start by explaining what condensation is, then I’ll list a few of the things you can do to prevent it. Feel free to skip ahead and just pick out the information you need.
What Causes condensation?
Condensation is caused by water vapour in the atmosphere encountering a cold surface and turning back into a liquid. This mostly happens in kitchens and bathrooms, but it can happen anywhere in your home.
There are two main factors that lead to condensation:
- The amount of water vapour in the room – If there’s nowhere for the moisture to go, then it will condense on a surface.
- Cold surfaces – If you have particularly cold walls, then water is likely to condense on them.
How Can You Tell if It’s Condensation or Damp?
If you’re reading this blog because you have water on your walls, then it can be there for one of two reasons: it’s either water condensing from the inside, or its water penetrating from the outside. Luckily, it’s very easy to tell.
If there are beads of water on the inside, but there’s no other damage, then it’s likely to be condensation.
If the paint has lifted like something is pushing it off from the back, or there is efflorescence or staining being pulled through from the inside of the wall, then it’s probably water ingress, and the rest of the information on this blog won’t be of any help.
Damp coming through from outside is a bit more complicated, because there are several things that can cause the issue. It might be that your damp course has failed, your cavity wall has been bridged, your gutters are blocked, your roof is missing a tile, or any one of another dozen reasons. My advice is to ask a builder to come and have a look.
How to Stop Condensation on Walls
Right, let’s start working our way through the things you can do to stop condensation on walls, starting with ventilation and then moving onto cold surfaces. If your walls are particularly cold, then ventilation alone won’t cure it. Equally, if you have loads of water vapour in your rooms, then a thermal barrier alone won’t solve it either.
This just means that you may need to address both issues.
Improve Your Ventilation
The idea behind ventilation is easy; it gives the water vapour somewhere to escape so it doesn’t condense on your walls.
Bathrooms and kitchens should always be fitted with an extractor fan, and that fan needs to be well maintained. Bricked up fireplaces need to be vented. The other thing you can do is add the odd airbrick and open windows when needed.
Anti Condensation Paint
Anti condensation paint works by creating a thermal barrier on your walls. This means the walls that water vapour encounters aren’t as cold, so less of it condenses. You can use most anti condensation paints as an undercoat, ready for you to paint over with a durable emulsion like eggshell or durable matt.
Anti condensation paints are a very easy fix, but they do come with a drawback. It isn’t like normal paint because it contains an insulating material (different anti condensation paints use slightly different insulating material, but they all work in the same way). The upshot is that the finish is slightly textured. This puts a few people off, particularly if the walls are perfectly smooth to begin with.
I’ve used a few anti condensation paints over the years. I think the best is probably Coo-Var Anti Condensation Paint. I’ll link a couple of suppliers below.
Wallrock Thermal Liner
This is an insulating lining paper. It’s a massive step up in terms of performance compared to anti condensation paints, but it’s a lot harder to install. It’s quite thick, so it takes a bit of effort to install it neatly, particularly in a small bathroom or shower room where you don’t have a lot of room to work.
Once it’s on the wall, you can tidy it up with caulk and filler, before installing normal lining paper over the top. Wallrock Thermal Liner comes with a specialist paste that you should use. Make sure when you come to apply normal lining paper over the it, that you use a grippy paste like Beeline Red Top.
There are other thermal lining papers on the market, but Wallrock is genuinely your best bet. Some of the others I’ve used don’t come close.
You can order Wallrock Thermal Liner from most trade counters. I tend to get mine from Crown Decorating Centre because I have a trade account with them (give them a few days’ notice), but I’ll link a couple of online suppliers below.
Use Emperor Paint Outside
This may seem a little, ‘out there’, but coating the outside of your home with either Emperor Masonry Paint for painted walls, or Emperor Masonry Crème if the walls are unpainted, will keep your walls warmer.
Both coatings are hydrophobic and breathable, which means it keeps them a lot dryer, and this leads to them retaining heat better. So, doing this will cut down on the amount of condensation on your interior walls.
Click here for product details.
Other Tips for Dealing with Condensation
We’ve covered all the main points, but I thought I’d quickly rattle off some of the smaller ones.
Use a Dehumidifier
Dehumidifiers make a huge difference because they remove water vapour from the air. However, I don’t see them as a permanent solution. They’re big, bulky, and give off a light droning noise.
Don’t Dry Washing Inside
I work on a lot of rental properties, and one thing I see often is people drying clothes on radiators or maidens. This puts more water vapour into the air and leads to a higher level of condensation.
Maintain Room Temperature
Ventilation is still important, otherwise putting your heating on will just result in a humid environment and you’ll still have condensation issues. However, keeping your house nice and warm in winter will dry everything out. Avoiding big temperature changes will also help.
Install Double Glazed Windows
If you have single-pained windows, then the glass will likely be the coldest surface in your room, and that’s where you’ll have condensation issues. This can also lead to rotted window sills.
FAQs
Does a bowl of salt help with condensation?
Yes, to a point. Placing a bowl of salt in a room will absorb some of the water vapour from the air and prevent it from condensing on your walls or windows. However, the effect is very limited. A dehumidifier might remove a couple of litres of water from the air in 24 hours. A bowl of salt will only remove a fraction of that.
How to stop condensation on walls in a bedroom in winter?
If condensation is happening more during winter, then the most likely cause is cold walls. You should look to create a thermal barrier with anti-condensation paint, Emperor masonry paint, or Wallrock thermal Liner.
Should I wipe condensation from windows?
Yes, remove the water before it evaporates again and becomes vapour.
What dries up condensation?
A dehumidifier, heating a room, and ventilation will all help dry condensation.
What is the biggest cause of condensation?
Excess water vapour in a room encountering a particularly cold surface.
Does leaving a window open stop condensation?
Yes, ventilation gives water vapour somewhere to escape, which prevents it from condensing in your room.
Final Thoughts
Condensation is relatively easy to deal with. It’s only ever going to be down to either surfaces being too cold, or there being too much moisture in the air. This makes diagnosing the cause nice and easy. After that, it’s just about taking practical steps to alleviate the problem.
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