I have built a partition wall with a wood frame, OSB board followed by drywall. See image. I was advised to leave a gap between the wall and the boards of at least 4 mm, which I have done. In some places, it's probably 10mm (the wall I'm building against is uneven). What should this gap be filled with? Neither OSB nor drywall lies flush against the wall, so there's a gap that's a couple of centimeters deep as well. Is it important that what you fill with allows movement? Should I therefore fill with some kind of sealant? Latex sealant? Foam sealant? Or can I use something that becomes rock hard, like Finja Laga vägg? Grateful for answers.
Ok, thanks!