Stone Walls in Bathroom - How to prepare for Tiling?

Hi Forum,
I'm replacing the bathroom of my stone walled welsh cottage.
I've stripped the loose lime plaster from the 2 external walls & the lath & plaster from the 2 internal 3x2 stud walls. Both in decent condition, but stone walls probably need up to 20mm thickness to fill out mortar joints & even them out to a flat surface.
Plan is to tile the 4 walls, floor to ceiling & reinstate a shower over bath in one corner (stone wall on long side of bath, stud wall on short side with shower unit mounted on it - NB: Bath shown in the pic is being replaced & repositioned)

Basic question is: What's the best way of preparing these walls for tiling (in particular the corner where the shower over bath is – do I need tanking etc…)

Materials already purchased…
Ceramic tiles - 198x248, 10.5kg / m2
BAL Grip Tile Adhesive
BAL Microflex Grout with 2mm spacers
12.5mm Water resistant Gyproc plasterboard for stud walls

Many thanks in advance for any advice, and I have to say this forum is awesome - I’ve managed to renovate the rest of the house so far based on advice I’ve found here & I’m thinking of erecting a sign saying ‘House Renovation Sponsored by diynot.com”!

Cheers

Bring the stone walls level with render. Plasterboard walls around a shower should be tanked - if you're tanking the short shower wall, you might as well tank the other shower wall too.

Thanks for prompt reply gcol

Just want to check a few things before I get going:
1. Render mix? 1:5 cement / plasterers sand ?
2. Tanking? BAL WP1 Shower Tanking Kit?
3. How long to leave new render before tanking / tiling - 2 weeks?

Thanks in advance

Weefer

weefer said:

Thanks for prompt reply gcol

Just want to check a few things before I get going:
1. Render mix? 1:5 cement / plasterers sand ?
2. Tanking? BAL WP1 Shower Tanking Kit?
3. How long to leave new render before tanking / tiling - 2 weeks?

Thanks in advance

Weefer

Click to expand...

1. Yep that's fine.
2. Yep that's fine.
3. Yeah, 2 weeks minimum. If you've plenty of cash and want to tile next day, you can use Bal quickset render. Not used it myself though.

EDIT: Actually 48 hours if you want to use the Bal render, not next day.

Thanks for all the advice gcol,
Guess I'd better get rendering!
Cheers
Weefer

weefer said:

3. How long to leave new render before tanking / tiling - 2 weeks?

Click to expand...

2 weeks is usually more than enough for a finish "skim" but you should leave a cement render of any significance for around 4 weeks; apart from the residue moisture you could be tanking in there, cement doesn’t fully cure until around 28 days.

http://194.223.92.131/pdf/Technical...hnical Data Sheets/Bal_WP1_Tanking_System.pdf
Quote:
NEW CEMENT/SAND RENDERING: Before commencing tanking, allow new rendering to dry out by exposure to air for at least 2 weeks...

gcol said:

http://194.223.92.131/pdf/Technical%20Data%20Sheets/B%20&%20C%20Technical%20Data%20Sheets/Bal_WP1_Tanking_System.pdf
Quote:
NEW CEMENT/SAND RENDERING: Before commencing tanking, allow new rendering to dry out by exposure to air for at least 2 weeks...

Click to expand...

Well the fact sheet does say “AT LEAST 2 WEEKS”. Personally I would treat render the same as float & set plaster; I wouldn’t risk tanking a rendered wall I’d done after just 2 weeks. A 12mm+ cement/lime render can take some time before the moisture content matches ambient, apart from the cure time. BAL quickset cement (& I love BAL stuff!) may be an option but I’ve never tried it. All cement render has water in it which has to dry out &, surely, tanking a wall while it’s still basically wet can’t be a good idea as it will effectively seal in moisture!

Anyway, why aren’t you reading those bedtime stories to your kids ; that’s more important.

She's in bed and the missus is watchin' Hells Kitchen - so you're stuck with me!
I'm no real expert in rendering/plastering, but I can do it and it doesn't fall down. Have another look at that data sheet - using the tanking solution on new plaster is recommended after a minimum of 4 weeks. On render is a minimum of 2 weeks. Go figure.