Closing cavities when replacing windows?

[NeilPalfreyman]

Hi! I've been a "guest" user of this superb site for many years and have benefited from loads of advice just by reading posts and replies, so thanks to all the contributors! But the time has come for my first "proper" forum question, so here goes:

The question, put simply, is "what would you expect a UPVC replacement window installer to do as a matter of cause to insulate around frames when fitting? Would you expect them to use insulated cavity closures, foam filler or the like? What's industry "best practice"?

The background to the question (sorry for length of this) is as follows:

My property is a 1927 block/cavity/brick construction and a couple of years ago I had several A rated Duraflex windows installed by a local company. Whilst I'm quite happy with the quality of the windows, I've never been happy with the thermal properties of the replacements, suspecting lack of insulation around the frames. The windows and frames in particular are always very cold, we get condensation on the frames and in severe cold have even had condensation on our A rated patio door freeze on the inside! This can't be right and the thermal performance is hardly better than our old wooden frames.

We've reported this several time since they were fitted but nothing material has been done about it.

Recently (last week) I started stripping one of the rooms to re-decorate and I took the opportunity to remove the 20mm UPVC flashing strip that the fitter had used to make good to have a look at the interface to the cavity. I can see a DPC (at least in places) but apart from that the installer has not fitted any cavity closures, used any gap filler or taken any steps to insulate where the frame meets the cavity. This has been made worse by the fact that our cavity insulation was polystyrene beads and we seem to have lost it around the windows, presumably during the installation. The net result is that the frames are just sitting on open cavities with upvc flashing (inside and outside) being the only thing stopping cold air entering the room and the window frames.

I strongly suspect that the other windows and patio door are the same as they were all fitted by the same guys at the same time and we have had problems with them too.

The fitter has a 10 year guarantee and I want them to remove and re-fit them using insulated cavity closures. Do I have "reasonable grounds" for this? Is there any published "industry best practice" that it would be reasonable to have expected the fitter to have followed?

Any advice appreciated, particularly if it's backed up by published material that could form the basis of a case. I don't know if this will end up in small claims but I'm thinking along those lines at the moment.

 

[^woody^]

If you have only contracted him to replace windows, then that is all he is obligated to do. This would include a secure fixing, external perimeter sealing and internal making good

Cavity closers or sealing a cavity which was already open would not be his responsibility unless specifically stated as part of the contract

 

[rjm2k]

Doesn't that make fensa even more of a waste of time?

 

[crank39]

Fensa has always been a waste of time, regards this install you won't get an inspector pulling trims off to see whats behind, whether foam or cavity closers. Cavity closers are such a pain to fit anyway, never sit right in brickwork thats already built hence why they're not universally fitted by installers

 

[^woody^]

Just take the crappy cover mouldings off and squirt some expanding foam into the reveals

 

[crank39]

Thats the ticket

 

[NeilPalfreyman]

Thanks for the replies, guys. I was thinking of sorting it out myself using foam filler, but reason that the insulation would be far better and more effective with insulated closures?

I'm also wary of using foam filler; the external brick work is old lime mortar and I have read horror stories about brickwork being warped or pushed out by expanding filler, frames being warped etc.

There's also the principle; these weren't cheap!

If you have only contracted him to replace windows, then that is all he is obligated to do. This would include a secure fixing, external perimeter sealing and internal making good

Cavity closers or sealing a cavity which was already open would not be his responsibility unless specifically stated as part of the contract

There are a couple of problems (at least in my mind) with that: First of all; as a layman how can I be expected to know what I should include/exclude from a contract? I didn't even know cavity closures existed until I started researching why my new windows may be worse than the old. I bought A rated, argon filled units on the expectation that they would be an improvement. They aren't. Secondly, there's the loss of my cavity insulation around the frames caused by the fitting; hard to prove but it's my feeling they are actually worse than they were.

Another thought I had was to try and find a tradesman to remove and re-fit them with closers. Any thoughts on this? Too expensive? Too much hassle? Would they go back in okay?

 

[^woody^]

Cavity closers are primarily for new build. They are just a convenience for the builder and offer nothing to the homeowner. I think you are misinterpreting what you are reading

An insulated and closed reveal can be achieved in several ways, and it matters not how, as long add the result is the same.

Foam will not affect lime mortar in this context, and it won't push walls or frames. Expanding foam is ideal for this situation, and you will gain nothing by fitting closers retrospectively - in fact they are not designed for retrospective installation and will not fully seal any gaps

As for the Contract side of things, well you either ask, research or engage a professional to advise. Certain things can be implied into a contract, but not something like this

 

[noseall]

We use foil sandwich PIR foam board (celotex, kingspan etc) as cav' clodgers, that are first wedged then foamed in place.

The wedges are also made from shaped slithers of foam board. The foil sides obviously face the inner and outer leaves.

 

[NeilPalfreyman]

Just a quick progress update on this.

I did one of he windows myself - took the trims off, foam filled the gaps, stuck the trims back on with gripfill and re-sealed. It made a *huge* difference. The frames and window panes now stay warm, no condensation and the room is noticeably warmer.

So I had the installation manager of the fitting company out to inspect the installation and take him through my extensive list of complaints and show him what I had done to fix it.

To cut a long story short he agreed with almost all of them including the need to insulate between frame and brick/blockwork. So he's sending a team out in a couple of weeks time to strip the flashing off, foam fill the gaps and re-fit all of the other windows.

Best of all he's agreed (in fact he suggested) to take the patio door out completely, fill the cavity as per the suggestion above (I'm providing the celotex) and re-fit.

I'll let you know how it goes.

 

[NeilPalfreyman]

As promised an update on this. Following my complaints different pair of fitters from the same company have been back out over the last couple of days and, with me standing over them, have done a very thorough and professional job of sorting my problems out.

What they found shocked even them; no foam filler used at all, even when gaps between frames and walls were as large as 10-15mm, use of D profiled cloaks rather than flat edged cloaks (impossibel to get a tight fit up against the frames) no "notching" of cloaks around the "trays" that the windows sit in in order to get a tight fit up to the frames, poorly packed units leading to sealing problems on a few of the windows, shoddy pointing around cills that had just crumbled away.

They've corrected all of this (apart from the poniting, which I did) by doing the following:

Removing all of the existing cloaks, both inside and out. Foam filling around the frames from the outside and where required also from the inside. Re-fitting new, cloaks with straight edges on the frame side, on a bed of sealant. Sealing the cloaks to the frames with liquid plastic and the cloaks to the walls with caulk. On the outside they have done the same but have used thicker, quater circle cloaks to provide additional insulation on top of the foam filler and have usd clear silicon between the cloaks and the walls. It looks *very* neat.

Although it's not been cold enough to say for sure the results seem very promising. The noise insulation (which is a great indication of thermal insulation) is very much higher, the frames feel warmer and there are certainly no drafts.

The story with the patio door is different. Much to my surprise the places where the frame was open to the cavity were few and far between - maybe a dozen places overall rather than a fully open cavity (which was what I expected) So they used the same procedure here as per the windows. Time will tell how much of an improvement there is, but again the noise insulation is already very much better.

The moral of the story? It's possible to fit A rated profiles and units (and get an A certificate) so badly the results are worse than the windows your replacing. Fitters cut corners if they can get away with it, so get a copy of the installation guide from the profile manufacturer and watch them like hawks to make sure they follow it!

I'll provide a final update once it's been colder.