Tiling on top of internal wall insulation (polystyrene)

Dec 14, 2007 9 Replies

Hi,



When I convert a room into bathroom (and get planning permission - thanks for note) I want to insulate the walls. The house is a Victorian brick-built end-of-terrace and the two external walls are absolutely freezing (although we *are* in the Hertfordshire polar winter currently).



As I understand I have two insulation options:


  1. External insulation


  1. Internal insulation



I don't want external cladding on my lovely two-tone Victorian brickwork.



So I need internal insulation. One wall can be dry-lined, insulated and plasterboarded as the room is big enough to take this loss of depth. However, the other external wall "abutts" the door frame and there is a 2cm "return" before the door frame on the internal wall. So, another drylined wall is out of the question - because I wouldn't be able to open the door.



If I use polystyrene sheets against the wall underneath ceramic tiles


  1. Would this setup this result in any thermal insulation benefit?


  1. Would this polystyrene surface be strong enough to support tiles or will the weight of the tiles pull the polystyrene away from the underlying plaster?

  2. If I had the plaster hacked off right back to the brick, could I get enough depth to usefully dryline and insulate this wall?


Thanks



Clive


I think every little helps, especially in reducing condensation.

I wouldn't put ceramic tiles over polystyrene. They would probably stick quite well but any little knock could crack the tile.

In my house you'd gain about 15mm that way.

Have you thought about tile panels? Not a great choice of designs, but only 3mm thick and most of that is the polystyrene backing.

Use polyurethane board: 25mm pu = 40mm eps

Even so I'd put a layer of plasterboard over the top.

Foam alone is not QUITE stiff enough to be safe for tiling..

Sorry, if I implied otherwise, it wasn't intentional.

Nice one. Looks like very useful stuff

ooops, sorry, top-posting.

Probably because its aimed at the electric UFH market, where levels are a big constraint. It's very space efficient, so you gain back some thermal efficiency by trading 12.5mm of plasterboard for 10.5mm of polystyrene and 1mm of cement/fibre on each face.

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