Do i need hardiebacker on slc?

[Bob2]

Hi all, I am replacing my ground floor suspended floor joists as they are rotten...replacing with new c24 tanalised 7x3's at 400 centres with noggins and overboarded with 25mm hardwood plywood. I will be using mapei ultraplan over this to bring it level with another part of the ground floor. I intend to tile the hallway up to the front door with porcelain tiles. Can I get some advice as to whether I should be using hardiebacker on top of the slc or can i just prime the slc and tile onto that with a flexible adhesive and grout?

 

[Dave]

Hi Richie. Is this a mixed substrate?

 

[Bob2]

Hi Richie. Is this a mixed substrate?

Hi Dave...no not the area to be tiled,...purely over ply and slc. This is another entrance to my property.

 

[Dave]

Hi Dave...no not the area to be tiled,...purely over ply and slc. This is another entrance to my property.

How much height do you need to build up on the ply.

 

[Bob2]

How much height do you need to build up on the ply.

It'll be approximately 10mm slc on top of ply.

 

[Dave]

Im just not a lover of ply.
hardibacker used to do a 22mm T & G board.

 

[Bob2]

Im just not a lover of ply.
hardibacker used to do a 22mm T & G board.

I get that Dave....it's not ideal but I wanted to bring the floor up level all over before I tiled by more than an inch. So can I tile direct on to the slc over ply or should i glue and screw 6.m hardiebacker on top then tile on to that?

 

[Dave]

I get that Dave....it's not ideal but I wanted to bring the floor up level all over before I tiled by more than an inch. So can I tile direct on to the slc over ply or should i glue and screw 6.m hardiebacker on top then tile on to that?

I would put Hardibacker over the ply , then level.

 

[Bob2]

I would put Hardibacker over the ply , then level.

Sorry Dave...do you mean glue and screw hardiebacker to the plywood and then self levelling compound over that? What benefit does that give me rather than the other way round? I don't mean to question you...just to understand you.

 

[Dave]

Sorry Dave...do you mean glue and screw hardiebacker to the plywood and then self levelling compound over that? What benefit does that give me rather than the other way round? I don't mean to question you...just to understand you.

Imo , it creates a stronger bond for the slc than to ply as ply isnt a suitable substrate as Stated in bs guidelines

 

[Bob2]

Imo , it creates a stronger bond for the slc than to ply as ply isnt a suitable substrate as Stated in bs guidelines

Thanks Dave...I get it...would I then be able to tile direct on to the slc with a primer?

 

[Dave]

Thanks Dave...I get it...would I then be able to tile direct on to the slc with a primer?

yes 👍

 

[Bob2]

yes 👍

Thank you Dave...appreciate you humouring me...and all your advice.