Problem substrate - crumbly stone wall

[Dean A]

This is the wall in question... (wall directly in front on the picture)

I have taken all of the previous tiles off, rubbed the painted wall down and stripped off the old adhesive. I am left with an uneven, crumbly wall :smash:

The surface is cracked, and it won't take the weight of the travertine large format tiles. My plan was to try and remove the surface layer and replace with fresh mortar.

I have also read of people using a thick layer of fast setting addy to even out walls.

Any last minute advice chaps?
​

 

[faithhealer]

Heavy tiles? hack the lot off and new concrete render

 

[Dean A]

Heavy tiles? hack the lot off and new concrete render

Yes heavy tiles, 12mm trav 300x300 format!

 

[faithhealer]

Play safe Dean, don't want one of them falling offf

 

[Dean A]

Play safe Dean, don't want one of them falling offf

Good advice :yes:

I will hack off the render, and start again I think. I will get down to Jewsons tomorrow morning to pick up some sand/cement render.

There is also Bal quickset render if my local tile supplies stock it.

I presume they will both be adequate for the job?

 

[DHTiling]

Dot and dab cement board onto the wall after you have removed the base coat back to brick..with rapidset..

quicker than rendering and will hold a lot of weight..

 

[faithhealer]

Dot and dab cement board onto the wall after you have removed the base coat back to brick..with rapidset..

quicker than rendering and will hold a lot of weight..

would that be 12mm board dave

 

[Dean G]

Maybe batten wall and srcrew concrete boarding to it to save time ?

 

[Dean A]

Dot and dab cement board onto the wall after you have removed the base coat back to brick..with rapidset..

quicker than rendering and will hold a lot of weight..

Would you mechanically fasten the boards to the wall, or rely solely on dot and dab?

Space is an issue in the bathroom, 12mm extra isn't ideal but may be the simpler option :ninja:

 

[DHTiling]

I don't mean 12mm extra... i mean remove all that background substrate back down to brick..then use the cement board...and yes use screws and plugs to mechanical fix

 

[White Room]

Screw through the board where a dab of addy is otherwise you could draw the board in towards the wall and give dips in the board. Wait till the addy has set before screwing

 

[Dean A]

Lots of mess, lots of fun today!

Pictures:

Most of the render is shot, it literally fell off with the tiles.

It seems some of it has been repaired in the past, as seen in the piccy:

It's seems to be stuck well, but its covered in paint and smooth plaster.

Should I take it all back and start again, or can I leave the good render on and somehow prepare the smooth plaster (take it off!) ?

:dizzy2:

New ply floorboards are going down later, after I have sorted the woodworm problem in the joists!!

 

[faithhealer]

looks like fun dean, couldn't see any good render though

 

[Dean A]

Plan today is to roughly render the wall to fill in the gaps between the stone, before dot and dabbing hardibacker to the wall.

I assume new render will be better for this job than simply packing the stone wall with single part addy?

EDIT: I picked up some fast setting non flexible addy to attached hardibacker to the walls (dot dabbing) - I assume it doesn't need to be flexible as it shouldn't be going anywhere! ?

 

[faithhealer]

Agree with that Dean

 

[Dean A]

Agree with that Dean

To clarify, you would roughly render before fixing the new boards?