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DPC underlay on wooden suspended floor causing damp?

Posted: Sat Sep 27, 2014 11:01 am
by thenorthernrob
Hi, I have just bought a victorian terrace (1880 ish), with solid stone block construction. The front room has a wooden suspended floor and the rear has solid concrete. Throughout there is laminate floor underlay with a built-in DPC.

In one corner there is a very specific damp patch, where a 'damp meter' gives very high readings inside the damp patch and very low reading immediately outside the patch. The floor slightly slopes towards this patch.

My question is, is it possible that the DPC on the wooden suspended floor could be trapping moist air and the condensation is running down to the corner causing damp to appear on the wall? A damp proofer has said I need to rip up all floors and pour concrete with a DPM and then inject the solid walls with DPC.

Any suggestions or experience wold be great.

Re: DPC underlay on wooden suspended floor causing damp?

Posted: Sun Sep 28, 2014 11:41 am
by welsh brickie
you don't need the dpc underlay on the wooden floor. that could cause problems,So long is there is adequate airflow through the suspended floor and no sign of rot then its ok.
The concrete floor can be painted with a damp proof paint to prevent damp

Re: DPC underlay on wooden suspended floor causing damp?

Posted: Sun Sep 28, 2014 6:43 pm
by thenorthernrob
Cheers Welsh Brickie. We are taking up the flooring to check the boards, but from underneath they look fine, in torch light anyways.

I've done a load more research and found that many Victorian houses don't need chemical DPC either and they can actually cause further damage in the long run. Apparently they are best left to breathe or ventilate. Any advice on that?

Re: DPC underlay on wooden suspended floor causing damp?

Posted: Mon Sep 29, 2014 7:30 pm
by welsh brickie
Yes its true, but it depends on the circumstance, if it looks dry after you have let it air for a while then it should be fine