Small flat upper storey concrete floor: DPM needed?

[Teige]

Hi all,

Any information or help with this would be really appreciated. My wife and I just bought an old council flat, 50s construction, on an upper storey.

The floor is a concrete slab, there's another flat beneath it. Neighbour says that flats used to be floored with tiles throughout, is that the reason for the troweled appearance of the slab surface in the photo? Am I actually looking at concrete slab or is it another material on top?

When I lifted the old floor covering (absolute mess of tiles, laminate, ply boards, underlays) some of the ply and underlay was damp, one board had mould.

We plan to level the floor, lay wet UFH in pre-grooved panels and cover with conductive underlay & thin engineered wood.
Even though it's the upper floor, do we need to put a moisture retarding layer over the concrete subfloor first?

What is the best way to avoid any damp issues from the floor?
I don't know where moisture is coming from in the concrete but presumably it needs to have somewhere to go... is sealing it on our side the best thing to do? Bit concerned that it could be a mistake to put in a DPM...

Thanks in advance!
Teige

 

[crazydaze]

You are looking at the concrete surface, albeit with remnants of the original tile adhesive still visable.

In an upper story, if there is moisture, it's likely to be from a leak somewhere rather than any 'damp issue'.

Have you checked that the deeds actually allow for wood flooring to be fitted? they often specify that this should not be installed due to noise through to other residents.

You will need to seal the floor if damp/moisture is present before laying the engineered flooring.