celotex/plasterboard

[Toml]

Hello,
I am currently converting my loft and need some advice having never done anything on this scale before. I had a loft conversion company do the carcass for me, but I am doing the rest. I would like to know what i should do first. I have put up 50mm celotex between the rafters, across the ceiling and along the ashlar walls and next i know i have to put up 35mm celotex and the plasterboard. Do I put up the 35mm first then the plaster board? or put then up together screwing straight through the plaster and celotex into the rafters? and should i start from the ceiling down or the floor up or even do the sloped surfaces first?

Any help would be appreciated,

Cheers people

Tom

 

[salem2000]

On my conversion the Celotex (Both layers) are fitted between the rafters, You must ensure a 50mm airspace is maintained between the insulation and the roof. this is for ventilation of the enclosed area to reduce condensation.

Then a waterproof membrane is fixed over all, make sure you have a good overlap on joints.

The plasterboard is then screwed to the wall/roof joists using 50mm drywall screws . the reason P/board is screwed up is, speed, less damage to board surface and personal pref.

As for where to start. The ceiling.

 

[Toml]

i have got a 50mm air space behind and fitted roof vent for correct air flow. The building inspector told me my second layer must go over the rafters as these are 'cold spots'. I'm using 60mm screws as 35mm of celotex plus 1/2 inch plasterboard is damn near 50mm so thought they would hold better.

Thanks for letting me know to start at the top though!

Still should i deck out the place with celotex first then do the plasterboard or just put them up together?

 

[salem2000]

I would just tack the Celotex in place with enough nails to hold in place then fit P/board. Easier than trying to hold two boards at once.

 

[Toml]

cheers, i thought that would be the case. someone told me it would be quicker doing them together but as i only have one pair of hands celotex first sounds the best option.

Ta,

Tom