I once installed a couiple of UPVC windows, in my house and the ony fixing I used was expanding foam from a can. I never had any problems.
Now i am about to install another on the first floor of slightly wind-prone gable end. Is expanding foam alone sufficient for fixng frame in place?
TIA
Al
You are joking right? :-) I hope the ones you installed are not high up and you kill someone.
C.
Define "slighly wind-prone", how much the glass in the curent window flex in reponse to gusts? Our old single glazed and over 3' square windows would flex about 1/2", t'was rather alarming watching it. The new 22mm DG units only about 1/4" but they are a different shape about 1'6" high and 3' wide.
For our windows they have frame fixings. Foam alone in less exposed locations is probably OK but it will flex and move thus may reduce the life of any silicone to building joint.
Builders frequently do fix windows with foam (a full circumference bond of polyurethane adhesive in effect - so very solid fix).
However a few traditional frame fixings helps achieve and maintain the desired position prior to foaming.
It's a recognised method. I don't like it but it's not as unusual as you think...
I go for frame fixings plus foam - the foam certainly firms it up.
Usually just wedges that keep the frame in place. Frame fixings, if any, are done when the foam has cured. At least that's the way all the fitters I've seen have done it.
Last pro fitter I same frame fixed then foamed - so it's obviously a matter of personal preference.
The Natural Philosopher wrote in news:ivpqdg$mv6$2 @news.albasani.net:
It sure saves a lot of faffing about! I wasn't sure about the longevity of foam though. I know it's a good adhesive when new, but I wonder if it weakens with age.
Al
"Dave Liquorice" wrote in news: snipped-for-privacy@srv1.howhill.co.uk:
I've never noticed the 3-ft square pane in the old window flexing, but then I never really looked. I know one thing: the frame cannot blow inwards. So it would have to get sucked outwards, which I is difficult to imagine! I think the roof tiles would blow away first. I think I'll quit worrying.
Thanks to all for the input,
Al
Its degraded by exposure to UV, so needs to be kept out of the light. However in this application none of it will remain visible so that's not a problem.
John Rumm wrote in news: snipped-for-privacy@brightview.co.uk:
Great - thanks.
window
You probably don't get the winds we do at 1400' and exposed. Gale Force 8 (above 40mph sustained) happens several times a year gusts with those are into the low 50's mph. Every so often it'll really blow F10 55mph sustained gusts above 60mph.
F8 isn't pleasant, rain is painful, hard to stand up and move sensibly about. F10 with gusts is down right dangerous, you have to lean so far into the wind that you are unstable, sudden drop in wind and you bite the dirt. Wind picks back up and you are quite likely to get bowled over. Needless to say we don't go out unless we have to in anything much above F7.
The all trees by us the nearby have the windswept curved look...
I'm not at your altitude, but my trees and shrubs all bend to the east.
Modern cavities are a PITA compared to older ones where the cavity was closed by a return on the end brick.
"Dave Liquorice" wrote in news: snipped-for-privacy@srv1.howhill.co.uk:
I've been at the helm of a 34-ft sloop, exposed to the elements, in a force
9 gale. The waves were about 15ft high. It was exhilerating - especially since I was only a trainee crew member! The only thing that stopped me losing my nerve was that the skipper was down below, apprently unconcerned. I always refer back to that experience when I need to guesstimate strong wind forces.Al
"Dave Liquorice" wrote in news: snipped-for-privacy@srv1.howhill.co.uk:
Same here, as a matter of fact, but they all bend to the North East and the window in question faces East, so it doesn't get the brunt of what nature throws at us.
Al
'They' glue aircraft together. Using a very much smaller contact area. Have you ever tried removing foam from brickwork?
I don't think people appreciate the difference between strength in tension and strength in shear. Glue is often only stressed in shear..e.g. the classic glued tenon and mortice joint, which is fine until there is 'rocking' when it fails in tension, not shear.
Which is why gap filling with glue requires a glue strong in tension as well.
Expanding foam is no particularly strong in tension, but a typical window frame is not able to rock sufficiently to rip the foam apart, especially in a rebated frame. And its quite a narrow gap as well.
So its the shear strength that counts. And here the foam elasticity is an advantage, spreading the stress evenly down the foam line, so there is no stress concentration ..
I've seen more screwed frames come awry than foamed ones.
Its standard industry practice to as has been said, wedge to get straight, then foam, then cut back and plaster the inside and mastic the outside.
In massive trauma situations - explosions - frames do not fly out, they glass does.
Strong winds will break the glass before they break the foam.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "AL_n" saying something like:
In other words, not daft enough to be up top. :)
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