Do i need to go overboard on cavity closers (fully filled cavity)

[Moonshine]

I am looking to buy cavity closers, and just has a thought.

 

As i am doing a fully filled cavity do i really need to buy a high spec cavity closer as the full fill will provide a good amount of insulation and there won't be cold air circulating in a residual cavity.

 

[Oz07]

I reckon the preformed ones are less insulating that the actually cavity wool. Possibly make it easier to get airtight seal though as you haven't got leaky cuts

[Oz07]

I would fit them if it were me, I then overlaid these with osb bedded on airtight foam. 

[Moonshine]

8 minutes ago, Oz07 said:

I would fit them if it were me, I then overlaid these with osb bedded on airtight foam. 

 

I am going to fit cavity closers, what i am trying to get at is, i don't think its worth buying high spec ones like a Kingspan Kooltherm cavity closer, and a cheaper one would be o.k due to the full fill.

 

e.g https://www.toolstation.com/ybs-24m-easi-close-eps-white-cavity-closer/p19768

[Oz07]

Yes I agree. I think all the cut to fit ones are pretty flimsy though so buyer beware

[Moonshine]

1 minute ago, Oz07 said:

Yes I agree. I think all the cut to fit ones are pretty flimsy though so buyer beware

 

cheers, for the majority of the windows i am looking to get premade ones done, its just around some areas i need to cut lengths down for doors and things.

[Johnny Jekyll]

On 07/07/2021 at 17:15, Moonshine said:

 

cheers, for the majority of the windows i am looking to get premade ones done, its just around some areas i need to cut lengths down for doors and things.

 

Moonshine, I have a nearly identical set-up to your walls (only difference is a 100mm cavity). May I ask, have you decided where you're getting your premade cavity closers from? And also your cut to length ones? And are they checked fit or flanged fit?

Thanks very much.

[joe90]

I didn’t use cavity closers but then again I have angled reveals, I just used expanding foam around the window wall junction then glued plasterboard to inner blockwork and screwed it to timber fixed to windows. 200mm cavity filled with rockwall batts.

[WWilts]

On 09/08/2021 at 10:01, joe90 said:

I didn’t use cavity closers but then again I have angled reveals, I just used expanding foam around the window wall junction then glued plasterboard to inner blockwork and screwed it to timber fixed to windows

How did you fix the timber to the window frame? (assuming that's what you did)

Glue? Screws?

uPVC windows here (Koemmerling)

[joe90]

4 minutes ago, WWilts said:

How did you fix the timber to the window frame? (assuming that's what you did)

Glue? Screws?

uPVC windows here (Koemmerling)

My windows were hardwood but I screwed the timber to the frame, you can still do this to UPVC.

[Iceverge]

1 hour ago, WWilts said:

How did you fix the timber to the window frame? (assuming that's what you did)

Glue? Screws?

uPVC windows here (Koemmerling)

Made an OSB sill and header. Then concrete screwed them to the inner leaf. 

 

Then added OSB reveals, again concrete screwed to the reveals. Used galvanised angle brackets to join them in place once finished. 

 

The boxes are not supporting the windows just themselves. They extend about 5mm beyond the edge of the window. Our windows are 82mm thick so there is still 77mm gap from the OSB to the outer leaf. 

 

I taped the window to the OSB. Used flexible airtight sealant and airtight paint to seal to the blockwork and the internal corners. 

 

Sorry about the photos. It's all I could find.