Bathroom Fitting Question

Fitter used plasterboard behind shower tiles. what can i do if it goes wrong?

I recently had my bathroom redecorated, the main thing being the retiling of the walls behind the sink, toilet and shower. When the old tiles were removed there was plasterboard behind which came away with the tiles, plus the false wall behind one wall of the shower (to make the room a right-angle) turned out to be a sheet of plywood which was damp on the bottom half. The builder replaced all this with new plasterboard and tiled over it.

I've since learnt that this is a really bad idea, and that waterproof cement board should have been used rather than normal plasterboard. I didn't say anything at the time of fitting as I didn't know anything about what materials should and shouldn't be used and have paid the builder/decorater for completing his work.

Having read about the possible consequences online, I'm really worried now that in the future this will deteriorate and fall apart. Should I mention my concerns to the builder who did it now, or just wait and see if something does go wrong before worrying about it? I'm not sure what rights I would have if something does go wrong. Any advice would be appreciated.

3 Answers

Best Answer


Gyproc moisture resistant boards are specifically designed and made for high humidity/moisture areas and ideal as a tile-backing board, they are green in colour as opposed to the white/cream/beige finish of "normal" plasterboard.

Fixed & prepared properly,they will do the job.

If he has used "normal" board then you are depending on the grout and additional sealant to keep the moisture away from the absorbant plasterboard....not a good idea

First check what was installed and if you still have concerns talk it through with the builder

Answered 7th Oct 2013


Member since 4 Oct 2013

In general:
Standard plasterboard (grey in colour) is a definite 'no' regardless of adhesive and grout used.
Moisture resistant plasterboard (green in colour) is ok but not the best option on its own particularly if a power shower is to be used.
Moisture resistant plasterboard combined with a tanking solution e.g. WP1 from Bal, is an excellent combination for most wet area applications. We have used this combination in hundreds of showers and have yet to hear of a failure.
In both cases, unplastered plasterboard has a recommended weight limit of 32kgm2 so consideration of tile to be used and suitable grounds to which the plasterboard is fixed is paramount.

Answered 8th Oct 2013

D B Enterprises

Member since 17 Jan 2013

A moisture resistant plasterboard ( green in colour ) fixed to a plywood sheet in turn screwed to the timber stud work would be acceptable .
The plywood should be at least 18mm and WBP graded plywood (water, boil proof)

Answered 7th Oct 2013

E.d construction (nw) limited

Member since 3 Oct 2013

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