Tiling floor preparation

[Dumbo]

Let me just put this out there .
British standard minimum thickness for plywood overlay is 15mm . Glued and screwed every 150 mm

 

[ash2710]

Let me just put this out there .
British standard minimum thickness for plywood overlay is 15mm . Glued and screwed every 150 mm

Is cement board the same as Hardie backer or no more ply? Will 6mm cement board be ok? Could this be placed over the 6mm plywood or would he need to remove that?

What is the process in fixing the 6mm cement board to the suspended floor?

 

[Dave]

Is cement board the same as Hardie backer or no more ply? Will 6mm cement board be ok? Could this be placed over the 6mm plywood or would he need to remove that?

What is the process in fixing the 6mm cement board to the suspended floor?

morning.
take up the plywood and replace with 6mm hardibacker boards , this in turn goes down on a serrated bed of tile adhesive and screwed down at 200mm intervals.
if there is a height difference to the concrete part, then the concrete section needs levelling to suit.
expansion should be installed at the transition where the substrates change and jf possible, a full tile either side for aesthetics if the setting out allows that.
another worry though is do this “builder” even know how to tile correctly if he doesnt even know the basics of preparation?? , I’d be very very sceptical

 

[ash2710]

morning.
take up the plywood and replace with 6mm hardibacker boards , this in turn goes down on a serrated bed of tile adhesive and screwed down at 200mm intervals.
if there is a height difference to the concrete part, then the concrete section needs levelling to suit.
expansion should be installed at the transition where the substrates change and jf possible, a full tile either side for aesthetics if the setting out allows that.
another worry though is do this “builder” even know how to tile correctly if he doesnt even know the basics of preparation?? , I’d be very very sceptical

Good news! The plywood will be ripped up and replaced with 6mm tile backer

Can any type of adhesive be used to secure the boards?

Do the boards need to be primed with Bal sbr bond?

 

[Tony_C]

If its hardiebacker board then any cement based adhesive to secure it down, it should be laid in a brick bond and also scrim taped and sealed with the appropriate tape. No need to prime if it's hardie as per manual, some may.

 

[Dave]

Good news! The plywood will be ripped up and replaced with 6mm tile backer

Can any type of adhesive be used to secure the boards?

Do the boards need to be primed with Bal sbr bond?

As Tony just said. And Use the hardibacker scrim as it’s alkaline resistant.
Good luck.

 

[ash2710]

Thanks all
So the following has been agreed to be carried out

6mm tile backer to be fixed in staggered joints leaving a gap for expansion around the perimeter

Tile backer to be primed All sides for belt and braces and peace of mind with bal sbr bond

As its a suspended timber floor, a flexible adhesive will be used to secure the boards with 40mm screws every 200mm

Tile backer scrim tape to be used for the butted joints between the boards

Out of interest does the concrete floor side need to be primed?

 

[Tony_C]

Concrete needs primed also yes.

Can you just confirm what backerboard you are using. Just to make sure you are getting the correct advice here. for e.g. no more ply uses a tubed adhesive out a gun.

 

[ash2710]

Concrete needs primed also yes.

Can you just confirm what backerboard you are using. Just to make sure you are getting the correct advice here. for e.g. no more ply uses a tubed adhesive out a gun.

Looking at the invoice it states 1220x1200x6mm multi pro moist sure tile backer

 

[Tony_C]

multi pro moist sure tile backer

OK thanks, I have tiled to these boards before, they are quite nice to work with. similar to BAL boards. I think i actually read before they could be made for BAL by them? Anyway they do require priming and they actually state they tested with BAL primer.

The rough side of the board should face up also.