Damp proofing concrete floor in room without DPC Damp can be a major issue in the home. Find answers to questions or post your own here.

[nakbrooks]

I'm replacing a suspended timber floor with a concrete floor. This is partly because the current floor has rot but mainly because I want to install underfloor heating.

Materials (in order from ground up) will be hardcore, blinding, DP membrane, insulation, concrete, screed with heating pipes embedded in it and ceramic tiles.

I will have insulation around the perimeter, sitting on top of the DP membrane and ending below the tiles.

The walls do NOT have a DPC (it is an old victorian building with solid stone walls).

My question is, how do I detail the joining of the slab DP with the walls?

I plan to carry the slab DP membrane up the walls, behind the perimeter insulation to 50mm aboive the finished tiled surface, hiding it behind the skirting (which will sit on top of the tiles).

Is this the best approach, or should I strip off plaster and carry it much higher (how much)?

There is no evidence of rising damp in the walls.

Many thanks

[thedoctor]

The membrane should be tucked into the wall at DPC height. See our project on ground floor slabs

https://www.diydoctor.org.uk/projects.htm

[nakbrooks]

Thanks for response Doc.

I've read the project, but my problem is that the walls don't have a DPC (they are victorian solid). Do I tuck the membrane in at the level the DPC would be if there was one (but theoretically this would leave a bridge as damp could go over the tuck) or do I tuck it in higher or do I just leave it flush against the inside of the wall behind the skirting?

Thanks

Nigel

[dcmoore]

Take a look at any one of our damp projects and ring the phone number for Property Repair Systems. They give free, no obligation advice and we recommend them. They will tell you what you need to do (if anything) and will also be able to supply you with anything you need to do it with but will certainly not try to sell you anything you don't need