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Posted: Wed May 11, 2005 9:40 pm
by Dickjall
I see the specification for rigid paving is for a DPM under the concrete sub base. But why, is it really necessary?
Posted: Thu May 12, 2005 11:30 am
by InfAddict
Hi, have you consulted the main website as instructed at the top of the page and in the Noticeboard forum?... it really does contain most of the answers you require.
Try here : FAQ - Do I need a membrane?
and here : Geo-fabrics
Posted: Sat May 28, 2005 4:27 pm
by Tony McC
There are two basic reasons why a DPM should be used benath a concrete slab and these are outlined on the Concrete Hardstandings page, but to summarise....
1 - prevents loss of mix water and so maintains correct w/c ratio while concrete undergoes initial cure
2 - protects underside of cured slab from attack by aggressive groundwater.