Two layers of Mapei Renovation screed?

[Rolandk]

Hi,
I've got a really rough, unlevel concrete floor which I want to lay UFH cable on and then cover with Mapei Renovation screed before tiling. Can I use a layer of the screed to level and smooth the floor first and then another layer on top over the cable. Will the two layersof screed bond together OK?

Cheers,
Roland

 

[kilty55]

i would install insulation boards first

 

[poynton phil]

You will need to level the floor first, with slc. Then fit insulation boards, then fit uhf, then cover the cables with slc. And then tile

 

[Rolandk]

Hi,

I have used insulation boards over the rest of the ground floor but this is a small entrance area and due to floor levels I can't use insulation boards in this area. I know it's not ideal but I'll have to go without boards here.

Cheers,
Roland

 

[poynton phil]

It will be a waste of time, and money to put ufh onto concrete without insulation.

 

[Rolandk]

Yes I know it's not ideal, whick is why I've used the Marmox boards over the main area of some 30 sq m. But the alternative is to take up the concrete floor and replace it 12mm lower! The area is only 1.5m square and it's to take the chill off the tiles. this small area will have it's own heating cable and thermostat. I need the tiles in this area to be flush with the rest of the tiles in the ground floor area.
I know it's a compromise.

Thanks,
Roland

 

[poynton phil]

Then yes, you should be ok to use 2 layers of renovation screed as I think you can go up to 50mm deep with it

 

[Rolandk]

Thanks Phill,
I was just concerned that the two layers might not bond together but if that's OK I'll go for it.

Cheers
Roland