Ask a Builder – Damp in my house

I’m getting damp spots in my one bed flat. What can I do?

First things first, start with the basics. Where is the damp originating? It could be coming through the walls, or it could be moisture condensing within the building and hanging onto the walls.

You can check if your home has high moisture by using this old trick – Place a small mirror in the fridge for 30 minutes then take it out and walk it into the room where your damp problem is worse. If the mirror fogs up that will be an indication of high moisture levels.


To confirm this for certain you will have to dry the room. Firstly, make a mental note of where the worst of the damp is. Dry the room out using an electric heater or dehumidifier. Let it run for 24 hours, you’ll have to leave the windows open (consider the security risks here). After a day, turn off the heater or dehumidifier and tape a piece of tin foil over the original damp patches. Leave for a while. If the foil appears damp on the room side it will be a clear sign of condensation.

Pro Breeze 500ml Compact and Portable Mini Air Dehumidifier for Damp, Mould, Moisture

If this is the case you need to evaluate if this is a lifestyle issue.

Some tips to deal with condesation:

  • Try to dry clothes outside if you can. We appreciate this isn’t always an option. If you do have to dry clothes inside, try to do it in a contained room with the window open
  • Make sure all extractor fans are working and are not blocked. This includes the kitchen and the bathroom
  • Keep drip vents and trickle vents open on windows
  • Ensure air bricks are kept exposed. We’re sure they’ve been installed for this reason
  • Personal security permitting keep windows open as often as you can. This is your best chance of keeping the building well ventilated
  • Try to keep furniture from being pushed up directly against walls. Even if you keep them away by 100mm this will allow a natural air flow in behind.
  • A very easy way to keep wardrobes ventilated is by installing air vents. They are easy to install and can be bought for less that £5. This will hopefully keep a air flow within and without the wardrobe.
  • Door Mini Circle Air Vent Grille

    Try your best to keep a constant temperature within the building. Difficult to achieve but warmer air will release moisture. Keeping the air at an equal temperature will minimise the chance.

  • While cooking try to keep pots and lids on anything boiling or simmering.

What if it isn’t condensation and water is penetrating from outside?

This is where it becomes a bigger job. Unfortunately there’s not a one size fits all option here. Unless there is an obvious ingress of water, from a broke downpipe or piece of guttering for example further investigation will have to take place. There could be many reasons water is getting in. Possibly from blown or cracked jointing or simply an upside down wall tie which is allowing water to track into the building. This does happen.  There are solutions as with everything in our game but it’s a separate topic altogether and something which should be tackled on a case by case basis.

Tool of the week – Makita Cordless Orbital Sander

Makita DBO180Z Cordless Body Only Cordless 18 V Li-ion Random Orbit Sander

The daddy of orbital sanders. 3 speed settings, connectable dust extractor (although we tape it to our vacuum) lightweight and fits in your hand nice and snug. The best thing? It’s battery operated. No need to nearly hang yourself working on a ladder with leads all over the place (writing from experience here!!) Snap a 5.0ah battery in and you’ll be sanding all day. After you’ve tried this you’ll never sand anything by hand again after.

Replacements pads are easy to come by, we get ours in Toolstation and are a piece of cake to put on. Simply peel the old one off, bin it and stick on the new velco backed pad. Piece of cake.

Thanks so much for reading this far. We hope you’ve found it useful .

Feel free to get in touch with any questions you might have. If you like what you’ve read and you think a friend may benefit from it too, please feel free to like, share and comment.

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