Marmox / Backer boards, will they support a bath?

[Kryters]

Simple question really. I'm rebuilding my bathroom floor which is in a first floor 1901 flat.

The Floor construction is concrete throughout the flat but in the bathroom to make it up to the level of the other floor levels there is a layer of compressed pumice with a screed on top (in total about 3" - 4".

I'm removing the pumice and screed with the intention of laying insulation and electric underfloor heating. I'll use a self leveling compound first to get a nice surface.

So my questions are this.
1) Are backer boards (Marmox) strong enough to take the weight of a bath (I'll probably be using 50mm).
2) Should I screed over the underfloor heating cables or just use tile adhesive?
3) Should I PVA the floor to seal it before using the self leveling comp?

Really appreciate any views on this.

Best Wishes[/list]

 

[jctilingservices]

Simple question really. I'm rebuilding my bathroom floor which is in a first floor 1901 flat.

The Floor construction is concrete throughout the flat but in the bathroom to make it up to the level of the other floor levels there is a layer of compressed pumice with a screed on top (in total about 3" - 4".

I'm removing the pumice and screed with the intention of laying insulation and electric underfloor heating. I'll use a self leveling compound first to get a nice surface.

So my questions are this.
1) Are backer boards (Marmox) strong enough to take the weight of a bath (I'll probably be using 50mm).
2) Should I screed over the underfloor heating cables or just use tile adhesive?
3) Should I PVA the floor to seal it before using the self leveling comp?

Really appreciate any views on this.

Best Wishes[/list]

1) yes
2)tile adhesive
3)NO, NEVER, use PVA. if you want to prime/seal it use either an BAL SBR
or BAL APD. Read the instructions on your SLC ( self levelling compound) and dont put it on to thick.