Flooring - applying concrete screed & DPM

1 Nov 2006
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United Kingdom
got a couple of questions on my floor...

First off, the system I'm using calls for 75mm screed using "C25 concrete with 50mm slump reinforced with polypropylene fibre tamped and floated".

2 companies I've contacted have said they can't do it because of the material used - is C25 with 50mm slump going to be particularly wet or something, and what's the best way to go about laying this?

Secondly - the beam n block system (blocks are polystyrene, otherwise seems to be "normal" beam and block) instructions say that you should lay the beams and infill blocks on a damp proof course, which I've done - but if using a damp and gas membrane (I am) this appears to go on top of the beam and block, continuing straight over the infill blocks to form part of the wall?!

Is that right? in essence (well, in really poor graphical terms :LOL: ) it's:

[] (Wall)
[]\\\\\\\\\\\\\\\\\\\\\ (screed rail / Reinforced C25)
------------------------ (Damp Proof Membrane)
[]¬¬¬¬¬[]¬¬¬¬¬[] (Beam and block)
-- (Damp Proof Course)
[] (Supporting wall)

Just seems odd (and not particularly strong) to me having 2 DPM only separated by a single course of block!
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