Tiling onto MDF - Question and Best Practice

Hello everybody.

We've been in the process of moving the bathroom around a bit such that a new stud wall (made of MDF) will now support the over-bath shower. The head of the bath will be butted up against this stud wall. We've also put up new (unplastered) plasterboard for the side of the bath to rest against.

Recently I asked a professional to come and quote for the work and outline how he planned to do it. He said he'd use waterproof adhesive and grout everywhere but did mention that he'd also have to unibond the MDF wall.

Now I've read a few posts here cautioning against using PVA as it may cause the tiles to slip if it gets wet. My question is this: Will the waterproof adhesive and grout suffice to prevent any water ingress thus preventing the PVA getting wet. I'd also be interested in people's opinions on the best practice for tiling on MDF surfaces that will see occasional wetness and whether PVA should be used at all.

Many thanks

Amanda

What type of MDF is it? at a minimum it should be Moisture resistant better still External grade. In either case I would not use MDF myself.

Most grout/adhesive will completely stop water, your best bet if you intend to keep the MDF is to tank it with something like BAL WP1 tanking system this will create a water proof barrier and you can tile straight onto it, preferably using the same make of adhesive & grout.

Don't use PVA unless the adhesive you are using specifically suggests it.

Jason

MDF cannot be used in any areas where moisture is present. No exceptions.

Thank you for your replies.

I have taken your advice and will put up plasterboard.

Thanks again

Amanda

better still use cement based tile backing board from Wickes totally waterproof and same thickness as p/board.

Thank you.

I didn't know about this Wickes stuff.

Amanda

Called Aquapanel.