Tiling to old cottage bathroom walls

[Ttt1601]

im hoping someone has a idea i haven't thought of for this one, tomorrow i night i have to go and price up a bathroom in an old cottage, i did the floor earlier this year, ended up having to put down an epoxy based dpm, with all relevant parties contacted, tec depts, a damp specialist etc etc. now the customer wants the ground floor bathroom fully tiled, the walls are flint lime and horse hair, im pretty sure it had that corrugated bitumen wall dpm installed in the 50s/60s then hardwall and skim over that. but not all areas have this as there is still a couple of little damp spots showing through on 1 external wall. my big question is, it is small room already i really cant afford the space to build a stud framework inside of the existing walls, if i batton it off the walls and fix to that i will penetrate any existing damp measures that are in place and i really wouldnt trust directly fixing to the existing walls.

so you bunch of genisus's any ideas???

 

[Time's Ran Out]

Don't do it!

 

[Ttt1601]

Haha cheers john I knew that was coming from someone

 

[Time's Ran Out]

Wouldn't want to disappoint!
The issue is whether any additional weight will hold to that type of wall construction without mechanical fixings i.e. Dot and dab water resistant plasterboard.

 

[Ttt1601]

I wouldn't want to trust the walls, there is areas where the plaster is blown, not in that room but in other room, even mechanical fixing into the horse hair and lime is hit and miss, I was hoping there was something I had missed as a new method really

 

[Chalker]

Can you construct a timber wall. Detached from the existing.

 

[Ttt1601]

Yea I can, ita just a very tight space, I doubt the customer would be happy about the losing any of the room, if its my only option then it is, as I say I was just hoping one you wise men knew something I didn't

 

[LM]

So how much room or depth have you got to play with then and let's try and work back from that.

 

[Ttt1601]

From the shower do to the opasite wall is about 5 ft but the sink is hung off it, don't have the dimensions to hand will have a remeasure tomorrow to know exact sizes, studding it out would mean moving all the plumbing, which iant a bad thing as I could change the layout but it is a very old cottage the reveals are already about 2 foot deep.

 

[One Day]

You could line it with wedi / kerdi board and treat it as a wet area.
12mm boards dabbed and anchored into the existing walls.
Even if you penetrate the existing damp-proof, you've just made a far better one - with insulation value too.