DIY Doctor

Main navigation

Condensation under Floorbaords

Postby tillymouse » Fri Jan 09, 2009 7:16 pm

I have bought a Victorian Terrace property- it's fair to say very little money has ever been spent on it! I only have electric heating downstairs!!

I noticed a damp smell coming up through the carpets, so I have lifted some of the floor boards- condensation has formed on the ends of the floorboards and joist closest to the external wall. I presume that this has been happening over the years as the ends of the boards are rotting

I have had a couple of airbricks added to increase ventilation but this does not seem to have resolved the issue. Any tips greatfully recieved as I'm fed up with having my floors lifted and the horrid damp smell.

Rank: Labourer
Progress to next rank:
Posts: 2
Joined: Fri Jan 09, 2009 7:06 pm


Simply Build It

Postby the specialist » Sat Jan 10, 2009 2:26 pm

Hi tilly mouse,

If the joist ends are wet and the edges of the floor boards rotting you may have a problem with the joist ends also rotting inside the wall. Lift the floor boards and try and push a large screwdriver into the joist where it goes into the wall. You need to do this at the bottom edge or side close to the bottom. If you can push the screwdriver in relatively easily then you have more than likely wet rot in the loadbearing ends of the joist. Also look at the bottom of the joist where it enters the wall ( a torch and mirror helps). If the bottom of the joist appears to be slightly lower than brick or timber packer it is on then it is compressing due to decay. Look for signs of wet staining and shrinkage of the sides of the timber. Timber joists affected by wet rot often become concave (slope inwardly) as the inside decays some times leaving the joist looking normal to the untrained eye.

If your still unsure you should get a timber specialist to look at it. If you leave it the problem will only worsen.

Once you have diagnosed properly what is happening you can then set about rectifying the problem.

If you provide further information I will attempt guide you as to the best way forward.

By the way I am professionally qualified in this respect.

the specialist
Rank: Ganger
Progress to next rank:
Posts: 87
Joined: Wed Dec 31, 2008 10:16 am

Postby tillymouse » Sun Jan 11, 2009 2:45 pm

Hi, thanks for the response. The joists don't go into the wall- they appear to rest on small walls under the floor. So I can see the end of the joists- have tried the screwdriver and it doesn't go in easily. I have removed some timbers from another part of the house which had wet rot and it is nothing like that.

I am getting a specialist in to have a look at it- although I can't see any signs of wet rot.

I think my biggest problem is that the timbers are just running with water- which I presume is condensation- and trying to get that sorted is the key, so any ideas about how to resolve that would be great.

Rank: Labourer
Progress to next rank:
Posts: 2
Joined: Fri Jan 09, 2009 7:06 pm

Postby TheDoctor5 » Fri Jan 30, 2009 10:11 am

If you type the key words of your question into our search box to the left of the site you may find the answer is already posted or is in the DIY projects section of the website. Every post goes through a monitoring process and using the search box may speed up your answer.
Posts: 1382
Joined: Tue Jan 20, 2009 9:17 am

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics