Bathroom extension - what to do with the walls before tiling

[Monkey Wrench]

Hi,

We are building a small ensuite in a first floor extension and are wondering the best way to prepare the walls before tiling. It will be a wet room with stone tiles to the ceiling in the shower area. We will use tile backer board for this but the challenge is what to do with the walls first. One of the three walls we will tile is a new thermalite wall, one an old pebbledashed brick wall and the other an old pebbledashed block wall. The old walls are a bit rough and I wondered what the best way of preparing them is for the tile backer?

Is dot and dabbing a good plan and then screwing the boards the way to go?

Any ideas much appreciated.

Matt

[Crooksey]

Remove all dash to get it level, then build a solid timber frame. Fix boards to frame.

Use a tanking tape on joints and then tanking solution over the tape to seal all corners and joins. You could cover the whole backer boards for piece of mind.

[Monkey Wrench]

Thanks Crooksey,

Another job for the weekend.

Matt

[royaloakcarpentry]

Sand and cement, then tile onto that.

Your idea of dot and dab for backer board.......Don't. The crystals in the bonding compound will not form correctly and this will affect adhesion.

[Monkey Wrench]

The Hardie Backerboard data sheets seem to suggest tile adhesive for securing boards to
walls and floors. Good advice on the dot and dab then.

Two very different approaches suggested so far - just after buying the backer board...

Thanks.

Matt

[royaloakcarpentry]

Do the frame in gypliner......quicker, more stable and overall cheaper than using timber.