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

2. 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

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

4. 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?

5. 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

Clive wrote:
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

2. 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

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

I think every little helps, especially in reducing condensation.

4. 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?

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

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

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.

http://www.neken.co.uk/

On Fri, 14 Dec 2007 01:55:46 -0800 (PST) Clive wrote :
If I use polystyrene sheets against the wall underneath ceramic
tiles

Use polyurethane board: 25mm pu = 40mm eps

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

Tony Bryer wrote:
On Fri, 14 Dec 2007 01:55:46 -0800 (PST) Clive wrote :
If I use polystyrene sheets against the wall underneath ceramic
tiles

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..

On Fri, 14 Dec 2007 14:56:57 +0000 The Natural Philosopher wrote :
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.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

Use wediboard or the like, it's designed for the job.

Tony Bryer wrote:
On Fri, 14 Dec 2007 14:56:57 +0000 The Natural Philosopher wrote :

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.

Bolted wrote:
Use wediboard or the like, it's designed for the job.


Nice one. Looks like very useful stuff

http://www.marmox.com/products_board.asp

Luxboard, aquapanel thermal, etc, lots of them around. There's a niche
in the market for a PUR or phenolic backed board, though, as they all
seem to be polystyrene-based - but maybe the cement face won't stick so
well to the other foams or something. It is great stuff though, no
phaffing around with separate layers of plasterboard (which is a pretty
poor tile substrate anyway).

Stuart Noble wrote:
Bolted wrote:

Use wediboard or the like, it's designed for the job.


Nice one. Looks like very useful stuff

http://www.marmox.com/products_board.asp

Bolted wrote:
Luxboard, aquapanel thermal, etc, lots of them around. There's a niche
in the market for a PUR or phenolic backed board, though, as they all
seem to be polystyrene-based - but maybe the cement face won't stick so
well to the other foams or something. It is great stuff though, no
phaffing around with separate layers of plasterboard (which is a pretty
poor tile substrate anyway).

Stuart Noble wrote:
Bolted wrote:

Use wediboard or the like, it's designed for the job.


Nice one. Looks like very useful stuff

http://www.marmox.com/products_board.asp

4 different thicknesses under 20mm, which might be useful for the OP

Stuart Noble wrote:

4 different thicknesses under 20mm, which might be useful for the OP

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.