Cavity closures and windows/doors

[clairelouisecook]

Our builder has built our window and doors apertures, but not covered the cavity. Before our windows and doors are fitted should I fit the premade cavity closures to the window and door apertures. How do we fit these and what do we need to be aware of i.e. not damaging any damp proof membrane. I understand the internal cill will be fitted after the windows please can someone confirm. Is there anything else I need to check that is done before the windows are fitted. Thanks in advance to those who respond this site is so helpful.

 

[Richard C]

Is this a new extension or new openings in an existing building?
Is the builder also fitting the windows?
Who is going to be responsible for finishing off the window reveals?

 

[clairelouisecook]

The window company will be fitting the windows not the door. We have changed the size of some windows in an old part of the building and the builder has fbricked up the space with block work so the aperture is the right size, but not put anything in the cavity. We also have windows and doors going in to an entirely newly constructed extension. In my ignorance I thought you cut a cavity closure on, window company puts on window and fits external sill, carpenter fits internal sill job done. What are the window reveals and where do they go?. What stages have I missed out in my ignorant understanding please advise and I can check what I have to do.

 

[Richard C]

The window company will be fitting the windows not the door.

Whoever fits the windows/doors must be FENSA registered & issue you with a certificate of compliance or you will need to advise Building Control who will inspect & issue you with a certificate (fee); no certificate could lead to problems when you sell.

We have changed the size of some windows in an old part of the building and the builder has fbricked up the space with block work so the aperture is the right size, but not put anything in the cavity.

I was concerned that new openings had been cut in which case you would need compliance with Building Regs & an inspection; the builder (or someone) should fit cavity closers; see also below.

We also have windows and doors going in to an entirely newly constructed extension. In my ignorance I thought you cut a cavity closure on, window company puts on window and fits external sill, carpenter fits internal sill job done.

Well that’s basically it; the cavity closers just slot into the cavity & are temporarily held in place with a few screws, the window/door is then fitted & will include an external cill; the windows/door will partly cover the plastic cavity closers which also act as a damp membrane. If it’s a new extension, I assume it’s been build to current Building Regs. & you’ve had the requisite Building Inspections? You will need a completion certificate when the work is done! The window company won’t automatically fit an internal cill unless you ask/pay them to; this would usually be fitted before any internal plastering work.

What are the window reveals and where do they go?. What stages have I missed out in my ignorant understanding please advise and I can check what I have to do.

The window reveals are just the bits of wall around the inside of the window/door, these are plastered out after the windows/doors/internal cills are fitted.

 

[clairelouisecook]

Richard thanks so much. Building control have been in on everything and we are using a Fensa company for windows and will get plasterer to plaster reveal. Any tips on cutting the cavity closures and I guess just make sure the screws are screwed in well so as not to unsettle the window.

 

[Richard C]

Any tips on cutting the cavity closures and I guess just make sure the screws are screwed in well so as not to unsettle the window.

A saw
The screws may not even be necessary if the closers are a snug fit (which they usually are) & even then are only to hold the closers in place until the window is fitted over the outside & the reveals are plastered over.