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Damp edges to solid concrete floors

Postby FranWhy » Sun Jan 02, 2011 8:25 pm

Hi, we have had problems with damp, mouldy carpets in 2 rooms of our 1980s bungalow. A surveyor's report says that humidity is 50%, walls are bone dry but after lifting the carpets found damp at the edges of the floor stretching 150mm from the walls in. He couldn't find any structural defects and there are no water pipes that run under these floors. He thinks that there may be a defect in the connection of the Damp Proof Membrane under the concrete floor with the DPC in the inner leaf of the cavity wall. He recommended having part of the floor carefully dug up to get a better look. He told us to find a local builder but I am wondering if we shouldn't use a damp specialist. Anybody have any thoughts on what type of person we should use? Also if the surveyor is right how is the problem corrected? Thanks very much.
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Simply Build It

Postby SPUD1701 » Mon Jan 03, 2011 7:08 pm


Your home should have been built with a dpc, usually with concrete floors is that the dpm with tie with the dpc at the inner leaf. The surveyor is probably on the right tracks. More inclined to think that they have never been tied together away back from construction time - poor workmanship.

I think probably having to get builder to cut back floor and check that dpm and dpc are tied together would be the best way to go.

Is your outside ground level higher than the concrete floor, if so reduce ground levels as this maybe bridging the dpc and allowinf moisyure to pass across to the inside. The dpc if not bridged should prevent moitsure getting through to the inside unless wall ties have been fitted incorrectly.

If the dpm is the problem, cut back concrete tie new dpm to existing lap up walls and tie into inner leaf of block work where dpc exists. Also advisable to fit perimeter insulation at edge between floor and walls to limit cold bridging approx 25mm.

Hope this helps
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Postby welsh brickie » Mon Jan 03, 2011 7:14 pm

take off the skirting boards and paint bitumin paint,on the concrete floor and the wall where the skirting is,That should stop it.
It seems a lot of expensive digging up the floor to find the problem and then having to repair it anyway.
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Postby FranWhy » Tue Jan 04, 2011 9:24 pm

Thanks for the replies - they are much appreciated.
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