I have to fit cavity socks to comply with building regs. It's a single story double skinned extension with a pitched roof. The internal wall is one course higher to allow for the pitch of the roof. The wall insulation goes up the whole height of the internal wall to the wall plate. I assume I fit wall socks in between the cavity wall insulation and the outer skin at the top of the outer skin? I note they come in 1.2 metre lengths, so how do i get around fitting in smaller spaces (i.e between the existing wall and the window?) Thanks