How to insulate walls with only 25mm to play with?

[nickso]

I'm currently ripping my bathroom apart for a complete renovation.

I was hoping to insulate between the plasterboard and inner leaf with foil faced insulation boards as it's a cold bugger of a room but as I have suspected for a long time I only have 25mm between the two. I don't really want to increase this depth if I can help it as it's already a small room and the shower won't fit as well then.

Looking on the Celotex (just picked randomly, not bothered about which manufacturer) website I can only see one product (TB4000) that is made in a thickness to suit my needs but it seems to be for laying over the thicker boards and not for cutting to fit between the studs.

Is it acceptable to cut it to fit between the studs or am I looking to do it another way?

 

[Pigeon85]

That will be fine to cut wickes have good prices http://m.wickes.co.uk/mt/www.wickes.co.uk/celotex-insulation-board-25mmx1200x24m/invt/190545/

 

[noseall]

What you are doing seems sensible, which is doing the most you can with the space you have.

Can you add insulation above the ceiling, i.e. is there loft space above?

Look at sealing around the window internally so as to cut out any draughts etc, the same with the floor.

Tape all joints regards the insulation and foam any gaps you see - ANYWHERE.

 

[nickso]

Noseall.....The bathroom is half under the eaves which is already heavily insulated and I am not removing the ceiling plasterboard as it is being cladded.

Took the skirtings off and there are holes everywhere which I will seal with foam.

The plasterboard is only 6mm thick. Is it worth using the foil backed plasterboard as well?

Pigeon....I saw the Wickes prices looked alright but the nearest store is 60 mile away. I'll check around. Cheers.

 

[jeds]

The plasterboard is only 6mm thick.

No plasterboard is 6mm thick. It must be something else.

My advice would be fit what you can between studs and re-board with 30mm thermal laminate plasterboard board. Normal plasterboard is 12.5mm so you are only losing 17.5mm - you'll never even notice.

 

[nickso]

Cheers, Jeds. Plasterboard is actually 8mm thick....I just checked.

Will look into thermal laminate.