boxing in concealed cistern - mdf - tile adhesive

1 Jan 2007
Reaction score
United Kingdom
please help - we have built mdf boxing in to cover the concealed cistern and pipework etc - no need for it to be waterproof - but used pva to seal it to be safe rather than sorry. Found that tiling was a problem and the adhesive wouldn't set. Would scoring the mdf mean that the tiles will hang properly? Or do we need to buy the waterproof cement backed aquaboard? and start again? At that crucial stage - so prompt responses would be great - many thanks.
Sponsored Links
Id say scoring wont harm, but a good covering of watered down pva, maybe even 2 or 3 coats..levaing a few hours between coats to dry should be ok. then leave for 24 hours b4 tiling....should do the trick...


now know i need to rip out the mdf and start again using high quality ply - but need advice on whether to pva or latex - and what adhesive to use - many thanks
Sponsored Links
ch427 said:
im no tiling expert but i know that pva+tile adhesive=disaster

The PVA adhesive will stop the water in the adhesive from being soaked up by the wood behind thus stopping the tile adhesive from drying. It can't dry out from the front because you've applied waterproof tiles on the outside face.

As you are only tiling over a cistern that shouldn't get wet just use plain old plywood and don't apply anything over it other than the tile adhesive and tiles.
Im just about to box a cistern and wall hung pan in.

i was wondering what type of wood to use myself, my first thought had been chipboard, but i take it thats no use either ?

The frame im using to hang the pan on seems to have a bit of flex in it so I think it needs to be pretty stiff otherwise the tiles will crack.

what sort of cistern did you use ?
The wall hung pans we fit usually come with its own metal frame that needs to be bolted in. Any boxing is then build around that. If we need to construct our own frame, we usually use 3 x 2 and make sure it is well and truly fixed to both the floor and the wall behind. 18mm ply is what we use to build our boxing in with prior to tiling. We then use a good flexable adhesive and grout such as the Bal and Mapie products ( you dont need to pva ). Make sure that the tiles directly behind the wall hung pan have 100% adhesive coverage, and is fully dried. Otherwise, cracking can occur when tightening up the bolts. A bed of silicone is often recommended between the pan and wall tiles too, but it gets really messy cleaning up the spill out.
im using a grohe rapid fit frame which went in pretty easy, i'll have a look at the flexible tile adhesive though.

who sells bal on the high street, b&q dont ....?
Topps Tiles are the only chain I know off who sells it, but any one that is flexable and suitable for timber should do the trick. You can use floor tile adhesive if you want, just make sure it is flexable.

The Grohe frame is a good little set up - before my supplier used to use them but changed to another brand a while back.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links