Cavity closures - during or after build?

[pilsbury]

Just doing a bit of online research and have noticed something. Some manufacturers have clips that hold the cavity closure in place that you set into the mortar as you build.

Other times when I see a build there are no cavity closures in place until the last minute once all the bricking has been done. How are these fixed in place?

Is one way better/easier?
Do the cavity closures go all around the opening of a window/door?

 

[garyo]

The cheapo ones I use are friction fit... you shove them in after the build. They come apart so that you can shave the polystyrene inner down a little if, say, your 100mm cavity has wandered down to 90mm somewhere.

They are a loose fit sometimes and I have to add an extra screw here and there. The last extension I did I also siliconed them in to reduce drafts... a bit OTT but hey ho!

 

[noseall]

The build-in closers are part of a larger system whereby the window or door being fitted is fixed in the same position as the closer.

 

[noseall]

.

They are a loose fit sometimes and I have to add an extra screw here and there. The last extension I did I also siliconed them in to reduce drafts... a bit OTT but hey ho!

I make my own with 100mm Celotex and DPC and then foam them in. I use Celotex wedges to hold them whilst foaming. Mine end up really solid and is the reason I switched from proprietary closers.

 

[^woody^]

Return the blockwork

 

[freddiemercurystwin]

Return the blockwork

WTF??

 

[rssteve]

Should they be 30 mins fire rated where a upvc window is fitted?

Building control have just made me ammend my plans as the cavity closers were not 30 mins rated.

 

[^woody^]

WTF??

Get with it

We build and I'll specify returned reveals in almost all cases. So much easier, and a much better job.

 

[freddiemercurystwin]

BC have insisted on insulated closers in Devon/Cornwall for decades ......

 

[tomfe]

Return the blockwork

LOL

 

[^woody^]

BC have insisted on insulated closers in Devon/Cornwall for decades ......

Move.

There is no specific regulation requirement for cavity closers.

 

[^woody^]

LOL

Sorry, you must have thought it meant back to the merchants. It did not. It's a building term.

 

[tomfe]

Hehe, it may be allowed but it's still not great design.

 

[garyo]

Should they be 30 mins fire rated where a upvc window is fitted?

Building control have just made me ammend my plans as the cavity closers were not 30 mins rated.

Doesn't the plasterboard clad over the top five you that?

 

[pilsbury]

I like the idea of returning the blockwork - makes the wall seem all the more solid and gives something decent to fix into for windows and doors. Just wondering what BC will say seeing as they are so hellbent on minimising thermal bridging....