Gypsum cc 730

[Lindgrenski]

I have built a staircase to our uninsulated attic which I am now insulating underneath and then putting up drywall. The staircase is 775 wide, so the cc is 730. I have cut a drywall sheet into three pieces to be able to seam on the height but noticed there are some gaps between the sheets, so I probably need something to seam with behind. I first thought of a masonite but maybe a drywall strip is better? Another stud won't work and I want as thin a piece as possible, without it being too poor.

So, masonite, drywall, something else?

 

[Kromo]

Picture? It wasn't easy to understand your description. It's always good to have a picture so even those of us who are slow in written language get it!

 

[Lindgrenski]

 

[Fredrik.engdahl]

A piece of 12 mm plywood or OSB works well. Or a metal strip

 

[JOW]

Yes, that can't be made crack-free when it's being puttied.
I would have placed a board preferably 28x70 but 22mm would probably work fine.

 

[Lindgrenski]

It will have to be osb as I don't want to install a thicker one behind, I don't want to compress the insulation more than necessary.

 

[Pumba]

I would probably add another 45a stud and then OSB and drywall on that, there won't be much insulation behind there.

 

[Lindgrenski]

I have 90mm insulation behind, so I can't frame with 45a.

 

[Pumba]

I have 90mm insulation behind, so I can't frame with 45.

I was rather thinking of extending the insulation with 45.
You basically get no insulation where the steps protrude on the backside.

 

[Lindgrenski]

I have already framed out 90mm on the stringers so I get 90mm insulation everywhere. I have placed the 45mm stud on the side walls 45mm away from the stringers as well, so I have 45mm insulation across the entire width, and then 45mm between the studs at the outermost.

 

[JOW]

Oh, the staircase becomes "cold" and the door downstairs?

 

[Lindgrenski]

Yep, insulated storage door.