In an earlier contribution to this discussion,
Paul Andrews wrote:

"Set Square" wrote in message
...

snip

If you're
*very* unlucky, the DPC membrane will be between the slab and screed
rather than under the slab!

Another poster has suggested that having the DPM membrane above the
main slab but below the screed is "normal" and that's what's been
specified when I had my plans drawn up. Why would that be unlucky?

Paul

It would be unlucky for the OP because he wanted to remove the screed and
screw some battens to the slab. He wouldn't be able to do that without
penetrating the membrane.

When my extension was built 3 years ago, that was done with the membrane at
the bottom (on top of a sand blind) then the slab, then a slab of rigid foam
insulation, and finally the screed on top.
--
Cheers,
Set Square
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