DIY Related: background for tiling a shower

[marko56]

Am refurbing a downstairs shower room - have stripped out the old tiles and am back to blockwork - the shower size is 1100 x 900 and will have 3 walls to tile - I have room to batten out if necessary - was thinking of using wedi/kerdi/hardibacker/aquapanel but seems costly (was quoted £41 + vat for a sheet of 2500x625 wedi board at CTD - I'm not trade so guess I'm paying full whack ) - looking at MR plasterboard and then tanking (have used a tanking kit before) - if done properly is this as good as using backerboard? The shower is a second shower and won't get a huge amount of use (couple of showers per day max) - any help appreciated.

[Aspect Tiling]

Plasterboard and a tanking kit/waterproof membrane will be fine.

[jay]

what size tile are you using

[marko56]

Probably 500 x 250 or 600 x 300 ceramics

[jay]

weight may be an issue backer board can carry more weight

[marko56]

on it's own the MR PB can carry 32kg/m2 - does this reduce after tanking?

[rooders]

could you use cement board?. also the fact your not in the trade prob would bot stop you getting trade prices. a lot of places all you have to do is say you want trade prices then you would be amazed at how much they knock off.. The prices they charge the general public are daylight robbery!

[Polishtradesman]

All gypsum based products are not suitable for wet areas, even if you put waterproofing liuqid. Cement board at least. Best is to use wedi or sth similar so you dont need to do tanking. It is big diffrence between gypsum surface and cement surface for moisture.

[Rich]

on it's own the MR PB can carry 32kg/m2 - does this reduce after tanking?

After tanking the max weight is reduced to 20kg/m2

[Sir Ramic]

After tanking the max weight is reduced to 20kg/m2

Not as far as I was aware ????

[Rich]

Not as far as I was aware ????

Im afraid so, on any substrate according to Mapei.

[Sir Ramic]

I remember being told that it was the same as the substrate by a few manufacturers...inc BAL, Ardex and Mapei !

[Rich]

I dont know about other brands but I asked the rep at Mapei when he was giving a demo as I have often wondered about it and he said that regardless of the substrate the pull off weight goes straight back to 20kg/m2. It makes sense I suppose.

[Sir Ramic]

But was Mapei mentioned ? Ardex say its the substrate that determine the weight load same for Bal. Although I dont like paint on systems anyway.
I am sure Dave will have the details for a membrane such as Dural or Schutler.

[Rich]

Yeah this was for Mapei paint on systems during a demo of the new aqua defense. According to him the strength of the substrate doesnt matter as you are now relying on the strength of the bond between the tanking system to the substrate. In tests the max weight of all the Mapei paint on systems was 20kg/m2.

[Sir Ramic]

Yeah this was for Mapei paint on systems during a demo of the new aqua defense. According to him the strength of the substrate doesnt matter as you are now relying on the strength of the bond between the tanking system to the substrate. In tests the max weight of all the Mapei paint on systems was 20kg/m2.

Then dont use it if weight is the issue.

[Rich]

?

Im not going to use it, just that somebody asked if the max weight of plasterboard was changed after tanking. Remembered the rep telling me that, thought I would share the info as I didnt know that before I was told.

[Sir Ramic]

But its not changed...only with Mapei paint on system.

[Rich]

Yeah, I dont know about other brands. Just thought that It might be of some use to the thread. I took it to include all paint on systems as the rep used to work for BAL but your saying that its not the same for other manufacturers and I wouldn't know to be honest.

[Dave]

Using membranes makes no difference to the weight capacity and this was direct from Schluter ... as for aqua defence or any liquid kit... then i haven't heard anything but i can confirm this quickly enough..for members.

[Sir Ramic]

No problem but your initial post seems to say that any form of tanking reduces the weight limits. This needs to be clarified.

[Sir Ramic]

Too be fair though I was suspect when Ardex said that their paint on system could cope with what ever weight limits were set by the original substrate.....Hence the reason I dont use paint on systems.

[Rich]

Fair point, I assumed that a paint on system was being used and assumed that the info I got from Mapei was for all paint on systems. Assumption, the mother of all muck ups.

[marko56]

thanks for all your help - i'm gonna try to get backerboard cheaper than quoted - I've seen marmox boards 1250x600x10 for £10 each @ tilefixdirect.com - I'll need 13 for my shower - using plasterboard would be £30 plus tanking kit say total £90 so seems worth it for the extra - has anyone used marmox board and is 10mm sufficient for walls - thanks for your help up til now

[Dave]

thanks for all your help - i'm gonna try to get backerboard cheaper than quoted - I've seen marmox boards 1250x600x10 for £10 each @ tilefixdirect.com - I'll need 13 for my shower - using plasterboard would be £30 plus tanking kit say total £90 so seems worth it for the extra - has anyone used marmox board and is 10mm sufficient for walls - thanks for your help up til now

Try PHG Wetrooms for your Marmox boards.. Waterproof Insulation Boards - PHG Wetrooms cheaper than those above

[Sir Ramic]

Seems we now have an answer to the question of weight limits with paint on tanking systems

[Dave]

We do yes and Mapei will post it here when they get this thread...

But to clear this up... paintable tanking systems DO NOT alter the weight limits for the substrate..

[Rich]

Sorry, I really dont want to push this any further but I am confused, does this mean that the info I was given is wrong or have I just made a mountain out of a mole hill by not being clear with my wording?

[Dave]

Your rep was wrong.. i too phoned my rep and he said the same as yours... but a call to technical cleared it up...

[Rich]

Right, I get it now. Sorry for the fuss I caused and thanks for putting me right