www.ultimatehandyman.co.uk

My son was replacing tiles in his bathroom prior to fitting a new suite. However, getting the old tiles off was a problem, so he took the wall back to the battens to reboard etc.
At this point he was called away by his work for a week and got a 'mate' to do a homer for him. Neat tidy job, used the correct drywall scews every 6 inches or so, no worries, except for one... he used 9.5mm plaster board. Personnaly, and I'm no expert, I'm not sure if this will be strong enough to carry the weight of the tiles.
We could have the wall skimmed, but that would just add more weight or we could tile directly to the plaster board. We're not quite sure which way to go with this one, hence the plea for advice. I fear he is going to have to rip it out and start again with 12.5mm board.
If it helps, the wall is 2200mm high, the tiles are 200x200x6mm and the battens are at 400mm.

Any advice greatly appreciated.
Cheers, Brom.

Your main concern is moisture and if any tiling is in a wet area then replace the PB with Aquapanel or similar cement based boards. A concern would be the PB sucking the moisture out of the adhesive so that the bond is not good enough so applying BAL primer might be an idea. Have a word with BAL technical http://www.bal-adhesives.co.uk/technical/faq. Also do not use the premixed stuff as the powder self mix is much better to use. Do not be tempted to use PVA as a sealer as it will reactivate if it gets damp and the tiles will come off.

I am not an expert in this but I am sure one of the tiling experts will pick this up and put you straight.

DWD

use a Bal, Marpei or Nicobond bagged adhesive and follow instructions as per sealing the plasterboard.

personally, I have no problem with normal plasterboards being used. It is the workmanship and how you look after the bathroom which leads to water damage to boards or not having any damage. We rip out poorly fitted showers 2 years after installation where the boards are completely effed. we rip out very well installed showers after 15 years and boards are perfect.

You will however have to find out if the plasterboard can cope with the weight of the tiles. Just having the tile sizes is not of much help to us as two different tiles the same size and thickness can weigh different amounts. Off the top of my head, I wouldn't be concerned about putting your tiles onto 9mm board.

ok it wouldve been better to use 12.5mm, but neat P/b will carry 32kgs per metr allowing 4kgs addy and grout, as long as theres no movemnent in the wall and its all sealed and grouted well then you should be fine, worth checking the boxes for weight per metr as ROC says you cant tell weight by size, PS if you skim the board you reduce the carriyng load by 12kg per meter (so you know for next time)

Gentlemen, my thanks to all three of you for taking the time to reply and offer your advice, it really is much appreciated. I've passed on your comments and my son has decided to go ahead with the tiling on the 9.5mm board. Ive also given him the address of this forum, he can learn a lot here.
Thanks again.
Brom.