Split level floor with no damp proofing - what to do?!

[Futuregrout]

Hi all,

I could really use some help with preparing my kitchen floor for tiling.

I have taken up the old floor: tiles on a 30mm screed, laid over what I was told was floorboards but is in fact a solid floor. Well, it is mostly solid. There are two holes, about half a metre square, where there the screed was laid directly over the ground. Also, there is a concrete slab which runs the length of one of the walls, about 600mm wide and 30mm deep. This creates a step in the floor of some 30mm. The screed layer had been used to level the rest of the floor up to the level of this concrete slab, and they had just tiled directly on to the slab. There is no damp proofing. This is an old house and I'm unaware of any damp problems but now the tiles and screed are off the floor, the floor does seem to be damp. I'll try to post some pictures soon so you can see it.

I'm a bit stuck about what to do next. I was all prepared for working on floorboards, and the (uneven) solid floor with no damp proofing has thrown me a bit. I don't want to bring the level of the floor up more than about 20mm as it will create a step. Can I just use a levelling compound and then hardibacker, or do I need to include a damp proof membrane? If so, when do I put this in?

Thanks!

Nick

 

[Ajax123]

What sort of depth above the existing floor do you have available. The simplest mod would be. Lay a 1200gauge polythene membrane the a new screed. You could use 35 mm of anhydrite screed or 50 mm of san cment screed in that scenario. The sand cement w ould need to be reinforced though. Once complete voila a dry floor... Well after the screed has dried that is.

 

[DHTiling]

Pics would be good..

 

[nybor62]

as above pics please

 

[Futuregrout]

Thanks everyone. Here's a picture of the "step" in the floor:



The "main" floor area varies in height by about a centimetre, and the concrete slab is about 35mm higher than this.

 

[bugs183]

Follow ajaxs advice, he knows his stuff!