One little room. so many issues

[iamray]

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I am about to tile our new kitchen floor which has been extended and is concrete. Half of which does not have a damp proof course (the old bit), whereas the new half does.

The floor is in 3 sections; the old original floor is 3x3 metres, the new floor is 3x3 metres and a strip joining the two is 300mm x 3 metres. I'm concerned about damp rising through the old floor and delaminating the floor tiles and the levelling compound which I'm about to lay, also any potential for future movement cracking the grouting and tiles. The floor is relatively level but they are at slightly different heights (variants of 5-10mm).

When I removed some of the steel pipes that were buried in the old floor screed I had to pull up some of the old floor screed which is about 20mm in depth. This leaves me with a hollow in the floor surface which will also need to be filled.

My question is should I?

a) Use a mapei paintable damp proof course that's reinforced and use a floor levelling compound over the top of that with flexible grout and adhesive.

b) Paint the old section with a damp roof course and use a decoupling membrane and pour a thin screed of approximately 30mm (all I have to play with).

c) Go down a different course of action?

I've attached some pictures of the floor to help to explain my scenario

Many Thanks
Ray

[Dave]

The mixed substrate should be allowed to breath IMO.. A Vapour Equalisation membrane like Dural CI can be used.. Not an easy substrate mix to combat but IMO Dural CI will cope.

[peckers]

I would repair your holes in the floor with ardex a46 http://www.ardex.co.uk/pdfs/ARDEX%20A46.pdf
then I would clean down and prime the area with no damp course and apply a suitable slc which is suitable to go under damp proof membranes this is done to fill any pinholes in the screed and to provide a smooth flat finish for the membrane to adhere to a damproof membrane I would go at least 500mm onto the area which has a membrane. Ardex arditex na is suitable. ARDITEX NA from ARDEX UK
Then i would apply ardex dpm to the area you have put the slc on. ARDEX DPM from ARDEX UK
Then I would apply another coat of ardex arditex na over the dpm and the rest of the floor area.

If you install A Vapour Equalisation membrane like Dural CI and you have to use a slc under it then you would still need a slc which is suitable for damp locations such as the ardex arditex na

[whitebeam]

Ultra 2 is also available for damp areas

[iamray]

Hello all,

Thank for your advice about these products, they weren't on my radar but they look like just the ticket.

Many thanks

Ray