Damp Proofing

Use of damp proof membrane in floor prep

Anonymous user 09/03/2024 - 2.30 PM

Hi, Hope you can help me with a question relating to my floor prep. I am in the process of building an extension at the back of my house. It is a large lounge area which measures 9m x 4.7m internally. The floor prep is as follows: - hardcore - sand - 1200 gauge DPM (Taped to the membrane coming out of the walls) - 2*100mm Celotex Insulation - 1000 gauge DPM (belt and braces) - steel mesh in concrete slab - screed Question - are there any issues with the use of the second (1000 gauge) membrane on top of the insulation? As a layman, I thought it would give me added protection against the possibility of damp rising through the concrete slab and also protect the insulation from the concrete properties. Can you please advise on this. Thanks in advance.