Preparation for uneven walls and ply floor. - Tile Advice

[Enrique volta]

Hello. I have a couple of questions, recently I went back to tiling x has been a lot of years, trying to do the right thing with the new ways .
I have to tile a wall, tiles 600 by 300 rectified porcelain brick patern , 10mm , the walls are not flat neither plumb , and on the window they want mitre, I was thinking in some backer board , dot and dab then fixing it with plugs, any advice , about which backerboards ?
Second , floor overboard wire ply 12 mm, cuite solid except one corner , a bit of movement, hardy backer 10mm with adhesive and screws , would be good ? Or anti cracking membrane? Or both tougher? Sorry for so long question, and thanks in advance .

 

[Joe8189]

Hey Enrique
You should be good using a 6mm backer board (any make) dot and dab to square everything, allow to dry, then back up with plugs. Make sure the corners are square and plumb at the window, it will make the mitred corners easier to match up.
If you can, eliminate the movement in the corner screwing board down it would be good. If you are sticking and screwing the hardy backer to the ply, you could get away with not using the de coupling membrane and stick tile direct to the board.
Good luck.

 

[Enrique volta]

Hey Enrique
You should be good using a 6mm backer board (any make) dot and dab to square everything, allow to dry, then back up with plugs. Make sure the corners are square and plumb at the window, it will make the mitred corners easier to match up.
If you can, eliminate the movement in the corner screwing board down it would be good. If you are sticking and screwing the hardy backer to the ply, you could get away with not using the de coupling membrane and stick tile direct to the board.
Good luck.

Thanks for the replay!. In the end I did jackoboard 12 mm on walls, dot and dab then screw. And on the floor, I take our the floor board luckily, and joist where rotten, I replace all of them and I made it strong and movement free, on top 18 mm ply plus 6mm hardy backer. About the plugs and screws for the jackoboard, I've used hamerfix plus the jacko washers , is any other metode better than other?