I plan to put some insulated plasterboard on the Garage side of the wall between the garage and the house because the two rooms on that wall are noticeably colder than all the other rooms in the house.

Hopefully something like a 50mm insulation board stuck to a 12.5mm plasterboard will make a decent difference next winter.

I’ve two questions....


1) Will there be any real difference between the cheapest Gyproc board at £25 and the top of the range Knauff board at £70? (I’ll need 6 or 7 boards)

2) Do I need “tapered edge” or “straight edge”?

I intend to stick them straight onto the breeze block garage wall with Something like pink grip Adhesive and then mastik around the edges. But I’m not sure what to do with the joins. Do I get tapered edge and attempt to plaster the tapered bits flush and then paint the whole wall, or is it easier to get square edge and fill the joins with polyfiller??

Many thanks for any help and suggestions.