Cavity closer Advice

Good afternoon all,

I am looking for a bit of advice concerning cavity closures. Iam fitting a set of uPVC french doors (building regs approval etc. all in place), house is modern constrution and is 11 years old. Outer wall is constructed of bricks to a height of 1 meter from DPC and then rendered block from there up. Inner wall is light weight block entirely. Cavity between the two skins is 75mm.

What is your experience of the 'ready made' cavity closers as opposed to closing the cavity in the traditional way of bricking the gap and using a vertical DPC as required.

The french doors are replacing an existing window, am I right in thinking that I will only need to close the cavity below the existing window sill level?

Any advice on these products will be much appreciated.

Kind regards
Mark

interesting point you've picked up on.

in new build they like to see you use thermabate cavity closures, which slot in nicely to regular sized cavities.

i have also had no objections (just frowns!) from b.c. when we haven't closed the cavity at all. bring the cavity insulation flush to the reveal, and let the plasterboard seal the cavity.this system allows you to fix tie wires right up to the reveal's edge.

if you do close the cavity with masonry, make sure the d.p.c is wide enough, and that the window is fixed in such a way that moisture cannot bridge.

Builder told me to use themabate+masterboard=Thermaboard or?