damp proof membrame

[mart]

Hi anyone know about damp-proof membranes, should they always be underneath a concrete floor or can they be on top of it. A damp proof guy told me that my dpm underneath the concrete was missing/ damaged but now a surveyor (over the phone) has said that it can be on top of the concrete. I have got a thin polythene sheet on top of the concrete and he said that this is my dpm but surely this cannot be it as it is too flimsy?

 

[DAZB]

The standard for Visqueen , as it's called , used as a Damp Proof Membrane is 1200 Guage. Check on your packaging that the membrane conforms to this and it should be fine. The Surveyor is correct in saying that it can be laid on top of the concrete but do be careful not to puncture it when laying a finish floor surface on top. If you need to join two pieces then a Visqueen Joining Tape should be used after overlapping the Visqueen by at least 6 inch.

 

[masona]

I take it you're talking about the concrete base and not the floor screed.

 

[mart]

Yep, the concrete base itself, what would the floor screed be made of though, is that something like sand?

 

[masona]

Sorry,I read your note wrong.You appears to have a concrete floating floor.Info on floating floor see this.

More info:
Floor screed are made of cement & sharp sand which normally go on top of concrete base for a smooth finish & the concrete base made of cement & 3/4 ballast sand