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Damp solid floor |
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| message from Lobster on 17 May 2004 |
Hi
When I pulled up the living room carpet, it was extremely musty and a
bit damp beneath, and I found the remnants of what looks like some
form of old DPC layer between the solid concrete floor and the
underlay - it was black, bitumeny, very old and disitegrating; looks a
bit like thin roofing felt.
Any suggestions for treating said floor? I know there's certainly no
DPC membrane below it, as I once had to dig a hole for installation of
water/electricity supply (and digging up and replacing the whole
ground floor is *not* an option!!). What would the roofing-felt-like
layer have been? Worth trying to replace it? Or should I try painting
the floor with bitumen-based paint? Or something else?
Thanks
David
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| Peter Taylor replied to Lobster on 18 May 2004 |
Hi David - remember the dampness is under slight pressure enough to lift
lightweight membranes, so I don't think paint would do the job. And I don't
think roofing felt would be durable enough and the dampness would probably get
through the lapped joints. That's why replacing the floor incorporating a
damp-proof membrane under the slab is the preferred method. But there are other
options. The traditional way of dealing with damp floors was to lay impervious
quarry tiles or wood blocks in hot pitch. In the 1930's it was quite common to
lay coloured flooring grade asphalt direct on the concrete slab, and more
latterly tanking, using multiple coats of screed with Sika waterproof additive,
has become popular. With all these ideas the moisture has nowhere to go and
frequently can spread into adjoining walls unless there's a good dpc at the
right level.
Another option is a ventilated plastic egg-crate membrane like Newtonite System
500 under a new screed, which allows the floor to breathe. This material is for
quite serious situations though and I see they do another product called Newton
Slimline which is laid over the screed. This looks like it could be suitable
for your situation. I don't have any experience of this product myself.
http://www.newton-membranes.co.uk/slimline.htm
Peter
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| Ian Stirling replied to Peter Taylor on 18 May 2004 |
Paint is just glue, with pigment in.
If the paint is adhered well to the concrete, then it can work well.
Getting it to stick is another matter.
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| Lobster replied to Tim Nicholson on 18 May 2004 |
Thanks all - this certainly seems worth looking into; many thanks!
David
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Archived message: Damp solid floor (UK DIY House Renovation)
