Will the plasterboard sag?

[tlundberg]

Hello

I am insulating an interior wall. The space being insulated is 57mm deep. I am putting 70mm insulation there. When you press on the insulation with your hand, it feels very soft and it seems easy to compress it the 13mm needed for it to be flush with the studs. But now, when I was about to screw in a drywall sheet, it was much harder to press it against the studs than I had thought it would be. Will the insulation make the drywall bow?

 

[vectrex]

I would think it's alright! Otherwise, it's not particularly complicated to split the panels in half, the fact that it doesn't quite fill the space doesn't matter for the soundproofing ability, I even think it's better to have a little air in there!

 

[tlundberg]

I kept the full thickness of the insulation boards. I have double layers of drywall and hoped they would be able to compress the insulation sufficiently. Now the entire wall is finished, and the straightedge indicates about a 2mm difference between the deepest valley and the highest peak. But when I placed the straightedge against the studs before I started with the drywall, they weren't 100% aligned either. So, I don't know if I should blame the studs, the insulation, or both for the wall not being completely straight

 

[ToRy]

One alternative would have been to wedge "strips" of 12mm plywood or similar on the studs inside the drywall, but it's a bit late for that now.

 

[tlundberg]

Nope, that would not have been an option, the room would have become too small I wouldn't have been able to fit the bed and wardrobes as I planned.

 

[ToRy]

Hehehe.... it's important to have the margins on your side!
I assume this is about the same wall that's being discussed for soundproofing in another thread?

 

[tlundberg]

That's correct

(and if anyone is curious, that thread is available here: http://www.byggahus.se/forum/isolering/209541-ljudisolera-befintlig-vagg.html)