Wind on windows

[Gary]

Anybody any idea how much suck the wind gives on windows.

I ask because I am using a plastic glazing pane. Held on by recommended tape and silicon sealer on 3 sides the bottom is not sealed , so as to allow the condensation to drain, and it really flexes in the strong wind giving a 'POP' as it goes. To prevent this in normal weather I have not totally sealed the window. there is a small hole around 1inch by 1/4 inch. this stops the flex in normal weather and for the room door being pened and closed. With storms coming I was wondering how much pull the wind will have on a panel 1.2meters by 1.2meters.

[The Natural Philosopher]

think its velocity squared, so impossible to say unless you know wind speed

[Chris Hogg]

And wind from different directions will produce different amounts of 'suction', depending on the angle of incidence, local turbulence, etc.

[LumpHammer]

I am not a structural engineer, but my copy of the "Structural Engineer's Pocket Book" (put it on your christmas list) gives these maximum wind loadings for various locations:

Scottish mountain top: 3.4 kN/square metre (ie. roughly 340kg force per square metre) Coastal Welsh town: 0.94 kN/square metre Suburban South-east England: 0.53 kN/square metre

[Dave Liquorice]

More likely push, I've not seen the window glass on the lee side here flexing, the exposed side is another matter.

We used to have "picture" windows on the exposed side single square pane of glass around 4' per side. When the wind got up those panes would flex a good 1/2" in the middle with the gusts and the running wind giving them a steadier flexure. This is with an F8 Gale blowing,

40 mph sustained gusting to mid 50's mph.

Unless you are exposed you're not likely to get winds that strong. Being out in an F8 is hard work leaning into it and keeping your feet. Anything loose outside disappears...

[polygonum]

Anyone remember the Grand Designs house in Scotland? I *thought* the windows blew in early on (very shortly after it was finished or even during the build), but maybe I am mis-remembering the roof blowing off in 2012?

Interesting nonetheless.

[Dave Liquorice]

square

running

blowing,

True enough.

But was asking about the forces acting on a window from the wind.

The transparent plastic sheet I take to be secondary glazing. The fact it "pops" indicates it has two stable states and it suddenly switches from one to the other. The OP says that the sheet is siliconed to the frame along three sides, this will stop/restrict the edges moving slightly, which they need to do as the sheet flexes.

Think of a plastic ruler in compression, it will bow one way but give it a shove it'll switch to bowing the other.

[harryagain]

If it is flexing, the unsupported area is far too big for that thickness of material.. Evantually it will crack and maybe sucked/blown out. Also security/burglary issues, Also scratches show up after it's been cleaned a few times. Child issues if on upper floors.

Also single glazing in this day and age????????????

The stuff is s**te, only suitable for small windows in sheds/greenhouses etc.

[harryagain]

Truely horrid building that. But then most were on GD in the latter days. (That roof is gonna cause problems.) (Are they doing a new series?) . Especially the ones built by brain dead architects. Useless impractical glass boxes. A lot don't even have curtains. Architects started off well. Pyramids and such. Reached their peak a hundred years ago. Sunk to the crap we see in GD. Why would anyone employ one?

I gave up watching GD. It's a program started off well and then deteriorated. No-one seems to watch it here any more either. At least, no comments anymore.

[charles]

Architects tend to build to their clients requirements. It's the clients who are brain dead, usually.

[Dave Liquorice]

You'll never stop things flexing as the appllied load changes.

I'll admit sat on the window cill watching a 4' square bit of glass move 1/2" or so with each gust is a bit, er, worrying. But these windows were installed in the mid 70's and none have ever blown in and we have had some serious winds in those times. Worst while we have been here was probably Christmas Eve 1999:

On plastic, yes.

I our case, legacy. All the single + secondary glazing has been replaced with 22 mm DG with Georgian bars (internal and external) dividing each 22 mm unit into 6 "panes" per window in a "sash-a-like" appearence. The whole window construction still flexs with the gusts but only about 3/16" at the most.

[Chris French]

Our windows are all single glazed. Though most have sliding secondary double glazing as well.

Listed building, with mostly Victorian sash windows, which are mostly in excellent condition. Replacing them would be expensive. We do have some rubbish 1970's -ish casement windows in the kitchen which of course are all rotting and they will be replaced when we redo the kitchen with double glazed units. We replaced the conservatory with a wooden one with double glazing a few years ago.

[Chris Hogg]

The windows of our wooden-framed conservatory are 1.8 x 1 metre (w x h), 3 off, facing SW, and they get the full force of the Atlantic gales straight off the sea, often gusting to over 70 mph. I don't know how thick they are but it's alarming to see how much they flex if you watch your reflection. But they've been there for fifteen years, and no sign of problems. When the local builder/carpenter was measuring up (it was to be an exact replacement for an earlier wooden-framed structure that had rotted) and I emphasised that it needed to be good and strong, he said 'Oh yes, I know, lighthouse standard'.