Damp Proof Membrane advice please!

lisal0u

Hi,

We are currently renovating a 1930's semi. We want to put electric under floor heating and engineered wood flooring down downstairs. I mentioned this to my plasterer and he said you've got quarry tiles and will need to dig up the floor and put in a damp proof membrane. Is this true?

The front living room and most of the hallway has a suspended wood floor and the kitchen diner and pantry has quarry tiles down. It doesn't appear to be damp at the minute but could we cause a problem by putting this type of flooring down?

Its really stressing me out because (possibly naively) I didn’t realise we would have to do this, it’s not in the budget and the builders have nearly finished!


Any advice would be greatly received!
Kind regards
Lisa

trogg

I would say your plasterer is correct, if original, your quarry tiles WOULD be the damp proof course.
To fit underfloor heating you would also need to replace the sub-floor (concrete) and would also need to have insulation under the heating, to stop the heat going into the ground.
I'm going by experience rather that expertise though,
Sorry it’s not good news.

lisal0u

Hi,

Thanks for your advice! I've been doing some investigating today and where the fireplace has been removed there does appear to be a damp proof membrane down. Its black and hard, not sure what it is.

If this is under all the quarry tiles would we need to bother with putting in a new membrane?

Thanks
Lisa

richardw

Would it be simpler to forget about the underfloor heating and just put a good quality laminate floor on top of the quarry tiles.

mikey72

I did a renovation, a house with quarry tiles over earth. There is no damp proof membrane, so if you lay a laminate floor, it will get damp underneath, and destroy it.
You have several options.
The cheapest is to use a damp proof underlay, such as
http://www.screwfix.com/prods/52649/Flooring/Flooring-Accessories/Foam-Underlay-with-DPM
with a laminate floor. But it will need to be level, and most quarry tiles aren't.
Second is to dig it all out, and lay a floor that complies with buildings regs, basically several inches of hardcore, several inches of insulation, a dpm, and then concrete.
The third way, (the way I went, as I couldn't comply to the regs for the new floor) was to have the existing floor covered with a hot asphalt, which sounds similar to your fireplace. It's a level, hard, waterproof surface, but I wouldn't like to put underfloor heating in it. As it’s poured over the existing floor, it will raise the height as well. I would only expect you have it in the fireplace, it most likely isn’t under the tiles, but have a check by taking a few up at random. Mine was better soil than the garden underneath.