Bathroom insulation/plasterboard advice

[Daniel1979]

Hi all, new here, hoping you can help me with my bathroom renovation.

Bathroom is a single storey extension with a new fat roof. Ive taken the ceiling down and insulted between the joists with 80mm Recticel. Also overboarded this with 50mm PIR.

I now want to retile the walls before renewing the bathroom suite. The walls are block with a cavity that are very cold at the moment. What is the best method of insulating these 3 exterior walls with minimum impact on the already tight room size? I see B&Q do a Gyproc Thermaline plus board in 27mm for £20. Would this help much or is it too thin?

Cheers
Daniel

 

[John D v2.0]

Anything helps but I'd probably go for a minimum of 25mm celotex type boards. That should almost half the heat loss through a standard wall.

 

[Daniel1979]

Thanks John, to save space can I fix this direct to the existing wall, board over with moisture board and then tile?

The basin and toilet cistern will need to be fixed to these external walls.

 

[John D v2.0]

Yes but the best way to reduce space requirement is to take the walls back to the blockwork and apply to that.

 

[endecotp]

Consider Marmox boards. Although their insulation value is lower than PIR PUR boards like celotex & kingspan, you can - I believe - tile directly on to them, so there is no need for plasterboard. This works out better when space is very limited.

 

[Daniel1979]

I'll take a look into them thanks, not heard of them before.

Cheers