Can I tile on this

[cuemanlew]

I would take off all the tiles then tap the plaster to see if its hollow or solid, you can hear the difference, If its solid then you should be ok. Prime it first (not pva). If its hollow its got to come off (will drop off anyway). What area is it in?

 

[Boogi]

My concern is that, my walls will be so much thicker if I re plasterboard, there is handle enough room for the bath as it is. I presume the old stuff can't be made secure with s sealer or bonding agent of some sorts, can the walls be re skimmed

 

[bugs183]

It's not a disaster so don't get stressed over it Boogi!
Tiling onto old walls like this is a real pain, and it will take so much more adhesive, time, patience and swear words to achieve even half of a decent job. They've been up a long time and they've done their job, but it's time for them to go.
I'd bite the bullet and strip all the areas you want tiling back to the brick/block. It sounds bad, but just bear with us all. Wire brush all the dust off, and then get a 5 litre bottle of SBR, water it down 2 parts water to one part SBR, and get a plant sprayer from b&Q etc and spray this over the walls, brush this in to the walls with a cheap wide paint brush. This with seal the walls and make everything new and nice.
Use 12.5mm plaster board or better still 10mm marmox boards (Insulation Express are really cheap and reliable), dab these on with board adhesive (lots of handy youtube vids). If you are short of space for the bath maybe you could board one wall and dab the other board over the roll of the bath.
This way you'll have lovely sound walls, that will be a million times easier than tiling on dodgy crumbly render or plaster.
Yep it'll add a few quid, and you'll have a bit of dust etc, but honestly go for it and you'll save a ton of agro when tiling.

 

[Boogi]

ok, i think i can just about live with this, marmox board sounds like the way to go, ill strip a wall at thee weekend and see what im left with, i presume i can tile directly on to marmox baord(do i need to seal again, this is in a bathroom). time is of an issue, if i fix the board to the wall with wall adhesive,how long before i can tile

 

[bugs183]

Marmox is fine to go straight onto, its waterproof, but if you really want to make it bombproof tape over the joints in the boards with waterproof tape, that way you've tanked your walls. No need to prime. Use a good quality cement based adhesive if you can.
Fix with board adhesive, not wall adhesive as it slump behind the board and not remain flat, plus board adhesive is dead cheap.
I'm not sure of the drying times of board adhesive,I'd say leave overnight if possible, it will tell you on the bag.