Fixing Cavity Closers

[Johnny Jekyll]

I'm fixing my cavity closers into place (normal flange fit closers pushed in).

I'm fixing the internal edges with small masonry nails into the mortar (with CT1 behind). Those have gone in well.

But using the masonry nails on the outside edge isn't holding the cavity closer against the wall. Mortar probably isn't solid enough.

 

Do the closers need fixing on the outside?

Surely they should be tight and silicon (in my case CT1) applied to seal them?

Shall I use flat flange fit screws (into plugs) on the outside edge? If so which ones?

 

Any advice / recommendations on doing this right, ready for the window fitters?

 

Thanks very much.

 

[tonyshouse]

I didnt use cavity closers, they cause too much air leakage and cracking - closed my own cavities without and cracking or air leakage and more cheaply too 

[Mr Punter]

I haven't seen silicone used for these.  If external is render, will this go on after windows and just return into the window frame?

[Dave Jones]

not that's its much help but subframes (pre built cavity closers) are much better as they are tied into the brickwork as its built up. 

[Linto]

I'm going to use a similar process for retrofitting them to my window reveals, but fix them with something like this to solidly attach them to the masonry.  Saves on using plugs. 

[Moonshine]

2 hours ago, Dave Jones said:

not that's its much help but subframes (pre built cavity closers) are much better as they are tied into the brickwork as its built up. 

 

Yep, I have used sub frames on my build, mainly so the window openings are fixed and hopefully the windows slot right in. 

[Johnny Jekyll]

Thanks for the responses everyone.

Our walls are already up, so pre-built closers aren't an option for us. Debated using them at the design stage but went with retrofit in the end.

Will have a look at those screws and other masonry screws thanks Linto, but would need to be careful the blocks don't crack / pop when drilling in. May need pilot hole to help.

Or may continue with simple little 25mm masonry nails where possible just to hold them.

The idea behind CT1 is to simply seal the edges, as you can't get the closers that flush to the brickwork (no matter how good it is).

[Faz]

I am building on the Fen and have a bit of a wind issue - the only thing that kept anything on the reveals was epoxy resin adhesive and screws.

[Dave Jones]

22 hours ago, Faz said:

I am building on the Fen and have a bit of a wind issue - the only thing that kept anything on the reveals was epoxy resin adhesive and screws.

 

another reason to use subframes, none of that hassle.

[James94]

We had issues with our reveals  and fixing  the cavity closers, very poor bricklayer. We ended running expanding foam up block and brick and holding in place with wood until set.

Regards. James