Insulation under tiles

[hard-work]

Outside wall, double brick, no cavity, plaster on wall. Bathroom.
New tiles to be fitted on the wall, need very thin insulation under the tiles. Anyone know which is the best to use?

thanks

 

[hard-work]

Any takers?

 

[oldbutnotdead]

Marmox- pricey but waterproof, think it starts at 10mm. Thermal performance per millimetre thickness is similar to Celotex/Kingspan etc but obviously 10mm won't do as much as 100mm.

 

[^woody^]

Complete waste of time and money.

 

[hard-work]

One aim is to prevent condensation emerging on the outside walls of a bathroom.

 

[John D v2.0]

Depends on your definition of thin.
Plaster off optionally, Batten out 50mm, celotex or wool between, vcl, cement board or whatever they call it, then tile on top. That would be reasonable.

 

[hard-work]

Directly under the tiles with no batons. No more than around 10mm. Insulation that is bonded to the wall with the tiles bonded to the insulation.

 

[Mike10]

What about some Dukkaboard. That should tick all your boxes.
I used it under the tiles for my kitchen floor and I have used it more than once when tiling the walls in a bathroom.

http://www.dukkaboard.com/products/original-panel/

 

[John D v2.0]

nice find, it's not quite celotex but 10mm is 2.528W/m2K so still getting on for the same as a single brick solid wall!

 

[^woody^]

One aim is to prevent condensation emerging on the outside walls of a bathroom.

The tiles will still be a cold surface for condensation in a bathroom if you put a foot of insulation on the wall.

 

[John D v2.0]

The tiles will still be a cold surface for condensation in a bathroom if you put a foot of insulation on the wall.

I assume he means mould, if there's a foot of insulation the condensation won't stick around long assuming there's some vague form of heat and ventilation in the room

 

[^woody^]

I assume he means mould, if there's a foot of insulation the condensation won't stick around long assuming there's some vague form of heat and ventilation in the room

Ceramic tiles will provide a suitable cold surface at a convenient dew point for air to condense on within any bathroom environment. Insulation won't make a bit of difference to that.

How soon the condesate evaporates away afterwards will depend on the OP's ventilation arangements, again notthing to do with insulation behind the tiles.

 

[John D v2.0]

Ceramic tiles will provide a suitable cold surface at a convenient dew point for air to condense on within any bathroom environment. Insulation won't make a bit of difference to that.

Agreed

How soon the condesate evaporates away afterwards will depend on the OP's ventilation arangements, again notthing to do with insulation

Not true, if the temperature outside is 0c then an uninsulated surface will always be so cold that any condensation won't evaporate quick enough to prevent mould. That's why there's a limiting u value given in the building regulations, to prevent this exact problem. As you mention, ventilation is also essential, which is also in the building regs.

 

[Diver Fred]

forget tiles - use Shower panelling. The plastic type is warmer.