The Natural Philosopher wrote:
Ian Stirling wrote:
The Natural Philosopher wrote:
Ian Stirling wrote:
wrote:
Hi,

Im in the process of insulating the roof of my garage.

I am planning on using 50mm Celotex between the rafters. Due to cost,
I was planning on using 25mm polysterene from B&Q over.

Would I still need the vapour barrier plasterboard ? Or if I ditch the
polysterene could I just tape up the joints where the Celotex meets the
rafters and use standard plasterboard ?
Take sheet of non-vapour barrier plasterboard.
Dilute PVA to milk-like consistency.
snip
This gets you a foil coated bit of plasterboard for well under 30p, and
in under 5 min or so.
Whereas the extra cost of the foil backed plasterboard is probably about
10p for the same area..

Oh well.
I got quoted an extra fiver per sheet.
Kitchen foil is only 10p/sheet or so.

enough for mow much? and then add in glue, your time...?

I didn't think plasterboard was much more than a fiver a sheet last time
I looked anyway..

I got quoted 10 quid a sheet for vapour barrier, 5 for not.

Tesco do foil for 68p for 3m^2.
It used about a litre of PVA for 24 sheets.

It takes about 3 minutes per sheet to do (once I stopped being silly and
getting a perfect mirror finish on each sheet of plasterboard, with no
wrinkles and perfect butting joins, which was admittedly very pretty,
but diddn't add a whole lot).