Hi,
I am building a new bathroom in my own house. The room is on the first floor in a newly built extension. There is no floor yet, just joists. I plan to have a tiled floor with electric underfloor heating. We haven’t chosen tiles yet but will probably go for large format floor tiles.
The floor joists are 70mm x 165mm @ 400mm centers with a span of 2.5m. I am planning on adding noggins to stiffen the floor and provide extra support for the boards.
At the moment I have considered 3 options for boarding the floor:
1. 22mm No More Ply T&G cement boards with noggins @ 500mm centers (because the boards are 500mm wide)
2. 18mm external ply with noggins @ 300mm centers, plus 6mm HardieBacker board on top
3. 25mm external ply with noggins @ 300mm centers
On top of that I am thinking of using Schluter DITRA-HEAT as that looks like a good way of providing underfloor heating and uncoupling in one go, then tiles on top of the ditra.
I was leaning towards using the 22mm cement boards on the joists (with noggins @ 500mm centers to support the edges of the boards) and the ditra heat on top of that, but reading the forum I get the impression that most professionals are using ply. Is there a problem with 22mm cement boards or reasons why ply is better?
I then considered using 25mm external ply instead. I think ditra-heat can be installed directly on wood and I thought cement backer board might be unnecessary with the ditra mat uncoupling the tiles from the wood.
But then I wondered if 18mm ply plus 6mm cement boards might give a stiffer floor than 25mm ply alone. But if I want cement boards then maybe it might be easier to forget the ply and use 22mm cement boards instead, i.e. back where I started.
I have been around in circles and I am not sure which option to go for, or if there is a better option / something I have missed. I plan to live in this house for a long time and I only want to do this job once, so I am more interested in getting it right than the cost of the different options.
Any thoughts or advise you can give me on this would be greatly welcomed
Thanks!
I am building a new bathroom in my own house. The room is on the first floor in a newly built extension. There is no floor yet, just joists. I plan to have a tiled floor with electric underfloor heating. We haven’t chosen tiles yet but will probably go for large format floor tiles.
The floor joists are 70mm x 165mm @ 400mm centers with a span of 2.5m. I am planning on adding noggins to stiffen the floor and provide extra support for the boards.
At the moment I have considered 3 options for boarding the floor:
1. 22mm No More Ply T&G cement boards with noggins @ 500mm centers (because the boards are 500mm wide)
2. 18mm external ply with noggins @ 300mm centers, plus 6mm HardieBacker board on top
3. 25mm external ply with noggins @ 300mm centers
On top of that I am thinking of using Schluter DITRA-HEAT as that looks like a good way of providing underfloor heating and uncoupling in one go, then tiles on top of the ditra.
I was leaning towards using the 22mm cement boards on the joists (with noggins @ 500mm centers to support the edges of the boards) and the ditra heat on top of that, but reading the forum I get the impression that most professionals are using ply. Is there a problem with 22mm cement boards or reasons why ply is better?
I then considered using 25mm external ply instead. I think ditra-heat can be installed directly on wood and I thought cement backer board might be unnecessary with the ditra mat uncoupling the tiles from the wood.
But then I wondered if 18mm ply plus 6mm cement boards might give a stiffer floor than 25mm ply alone. But if I want cement boards then maybe it might be easier to forget the ply and use 22mm cement boards instead, i.e. back where I started.
I have been around in circles and I am not sure which option to go for, or if there is a better option / something I have missed. I plan to live in this house for a long time and I only want to do this job once, so I am more interested in getting it right than the cost of the different options.
Any thoughts or advise you can give me on this would be greatly welcomed
Thanks!
