Ditra matting on top of Hardiebacker board?

[Chewie]

Good morning guys and gals,

Went to look at a job at the weekend. Hallway in a victorian house.
15m2. Floorboards down at present. Big skirting boards present too.

The owners want to replace the floorboards with 10mm Hardiebacker board with Ditra matting on top. They tell me Mr Hardie himself has recommended this.

I'm just wondering about trowelling matting onto cement boards. I've never done that before. You ain't going to get much time with the adhesive, surely.

I actually think it should be a thicker ply and then Ditra with vinyl adhesive.

Has anybody trowelled Ditra matting onto Hardiebacker board?

Thank you in advance guys and gals..... and you Antonio!

 

[Dumbo]

I think they are lying or misunderstood what they were told .

 

[Dumbo]

Also you shouldn't be relying on customers specifying your work .

 

[Waluigi]

10mm Hardiebacker doesn’t exist.

Not as far as I’m aware anyway. The common thicknesses are 6 and 12mm.

Overboarding the floorboards in 6mm might be OK but directly on to joists I assume is just a typo or we are misunderstanding you. Surely nobody thinks this is acceptable?

 

[Chewie]

I think they are lying or misunderstood what they were told .

I totally agree. I think they are hoping the tiles can go under the skirts....

 

[Chewie]

Also you shouldn't be relying on customers specifying your work .

Of course not. I can’t do it either massive skirts on anyway. They’ve done things round the wrong way and decorated first....!

 

[Spare Tool]

12mm Hardi isn't suitable and 22mm hardi is not available in this country, and ply over ufh is a bad idea, it needs to be a 22mm structural cement board like nomoreply or Giffafloor screwed to joists, so either the skirtings will need removing or tile up to them leaving an expansion gap and Silicon.

 

[Chewie]

10mm Hardiebacker doesn’t exist.

Not as far as I’m aware anyway. The common thicknesses are 6 and 12mm.

Overboarding the floorboards in 6mm might be OK but directly on to joists I assume is just a typo or we are misunderstanding you. Surely nobody thinks this is acceptable?

It’s heated in between the joists and they want to put Hardiebacker down onto

12mm Hardi isn't suitable and 22mm hardi is not available in this country, and ply over ufh is a bad idea, it needs to be a 22mm structural cement board like nomoreply or Giffafloor screwed to joists, so either the skirtings will need removing or tile up to them leaving an expansion gap and Silicon.

Thank you for this.

 

[Flintstone]

Is it screed over the pipes flush to joist top ?

 

[Chewie]

Is it screed over the pipes flush to joist top ?

I don’t know. Sorry.
To be fair, I didn’t know you could do that.