Window conundrum

[Mickwhitt 4,624]

Hi all.

We have a picture window in the front of our house. It faces due west so gets plenty of wind against it practically year round.

It's 4 metres wide by 2 metres high (13 ft x 6 ft six ish)

It's a uPVC framed thing which is six years old. It's not one since window but split into 5 bays, 4 small and one bigger one.

The problem is; it moves.

It flexes back and forth in the wind, not just a little. It comes in over an inch and when it moves back it pulls out the same sort of distance.  So the centre of the window is moving around two inches back and forth in storm winds.

This is pretty scary when you are sitting watching TV and the window is creaking and moving.

Window firm say its within specs, insurance people say its not their problem. Window fitter says reduce the size of the window substantially to cure the problem. 

I'm thinking of bracing the central frame by putting two pieces of vertical box section indoors, behind the uPVC members and anchored top and bottom. 

This will prevent the centre from moving so much while not impacting on the view etc.

If I do this it will either cure the problem at minimal cost, or show me another solution is required.

Any thoughts on the issue?

Suggestions or cautions?

Mick

 

[sjoemie himself 3,068]

Your solution sounds pretty good to me.

I'm a visual thinker so if you could share a picture of the current situation that might help.

[Sailman 1,291]

I think your solution is a good one. Can't picture one better.

[JoeM 7,874]

Question, is the movement essential?

Sometimes making things with more rigidity will cause a fracture. IDK 

Sure seems like a lot of movement tho.  

[ri702bill 8,321]

6 hours ago, Mickwhitt said:

I'm thinking of bracing the central frame by putting two pieces of vertical box section indoors, behind the uPVC members and anchored top and bottom. 

This will prevent the centre from moving so much while not impacting on the view etc.

If I do this it will either cure the problem at minimal cost, or show me another solution is required.

Sounds like a sep in a positive drrection.

How about bonding the frame to the added anchored uprights if they prove to be adequate ??

[Mickwhitt 4,624]

This is the window in question.

i dont really want to work on the outside of it so bracing the inside seems the best way forward.

Its supposed to have steel tubes inside the profiles but they are obviously not strong enough.

I know  what you're saying about making it too rigid, so I'm planning some kind of foam cushions on the brace pieces to allow some flex.

I'll post a video of the movement soon.

Mick 

 

[Stormin 9,981]

Sounds like a good plan to me, Mick. Allows it a bit of flex. 

[lynnmor 7,306]

Could it be opened to expose the steel?  My thought is to reinforce or replace the steel with something adequate.  Is there no warranty on the windows?  It does sound like the window companies over there are as slimy as the ones in the USA.

[Mickwhitt 4,624]

48 minutes ago, lynnmor said:

Could it be opened to expose the steel?  My thought is to reinforce or replace the steel with something adequate.  Is there no warranty on the windows?  It does sound like the window companies over there are as slimy as the ones in the USA.

You may be right there with the slippery window guys. Ever since we first got double glazing in the 70s window salesmen are on a par with estate agents and solicitors.

I'd have to remove the window to try and beef up the internal bracing, adding something inside is much easier. 

[Tractorhead 9,064]

It sounds for me not tooo horrible.

it may look impressive but it i believe it becomes more clear if you look a little closer to what happen really at strong Winds.

 

Your pictured and described sectioned Window results in all together 4x2 meter = 8 squaremeter.

 

Ok i try to Example what i mean with Windload based from official Beaufortskala

Windspeed in.       |    Windload in 

m/s   km/h   mph   |    Pa       kN/m2       Beaufort
16.     58.      36.    |   160,0.    0,160.       7.  known as „strong Wind“

 

don‘t underestimate the Windload on a Window in this size there is ( just for example)

at 36mph or 58Km/h Windspeed 160 Pascal a squaremeter  X 8 = 130,52 kilo  Windload on the whole Frameset.

Pressing on such a Frameset with a 130 Kilos is a lot of force.

 

for a 130Kilo strong pressure to this Structure i would think a inch bending is not nice, but also not a nightmare.

It depends also on how stiff and thick the Frameset itself is. How much does the Glass in the Window itself bends?

 

My Way to prevent this would start by enstiffening the upper Traverse from outside with a inserted T- bar to give the whole lenght structure more Resistance and Stiffness against the Windload side.

On the other hand, if you stiffening It too much, i believe the weakpoint will maybe move to another part.

 

By the Way, a level 7 Wind presses on our relatively new Windows thru the seals aside the Locking mechanism.

That is at least 4,5mm that thick are the Seals arround.

 

 

Hope that helps a little

[formariz 11,987]

Without seeing exactly how window is built it is hard to come up with a solution although yours sounds reasonable. As for the movement it is excessive reflecting a fault of some type in construction and or design. I have built and also installed manufactured windows larger than that and none flexed even a fraction of what you experience. 

[Tractorhead 9,064]

11 hours ago, formariz said:

Without seeing exactly how window is built it is hard to come up with a solution although yours sounds reasonable. As for the movement it is excessive reflecting a fault of some type in construction and or design. I have built and also installed manufactured windows larger than that and none flexed even a fraction of what you experience. 

 

Just a question @formariz i estimate, you built the Window Frameset made of Wood?
be i correct?

But As i read, mick was talking about a Plastic Frameset and this Plastic profiles i know where here frames are made from
bends for my opinion a lot.

The only differences where multilocks but they be extremely expensive.

 

A Wooden Frameset in my knowledge is much stiffer.
A Friend of mine working several years ago in such a Window Company and i helped him few Weeks to insert the Frames in Houses, that was my reason i ask you.  The only differences i remember out of this Time was the ammounts and the Sizes of the Windows on a same size Window frameset and the Locking system if it be a tilt open mechanism or multilocks with tilt open
of how much it will bend at Windload.

 

i don‘‘t wanna annoy or even bother you, your skills in that themes be shure much more than mine,
i just wonder that there should be so huge differences.

If we talking about different Materials, i can imagine it.

or maybe we have on this Site of the Pond all the same Bulls**** windowmaterials like mick.. 😎
 

[formariz 11,987]

@Tractorhead Not seeing a cross section, horizontal and vertical in this case, of the window in question it is difficult to assess what the actual problem is. Looking at the exterior of it and knowing what it takes to build something similar in appearance and proportions, I don’t see a substantial framework unless the interior is very different. For example, how thick is this window? With narrow “ mullions ” such as this one , the depth of the framework is a critical part. I suspect that this window is made up of different sized units merely attached together  to achieve one final look. The fact that it also has smaller units on the top adds to the problem since in this case the long horizontal member of the frame( if any) is key to its overall rigidity. Had these panes been one unit from top to bottom, I am sure problem would not be as severe. In any case that kind of movement is not only not unacceptable but it can be outright catastrophic. Sooner rather than later something is going to give. 
 

 I have built windows larger than that ,reason for it always being unusual sizes or shapes which required custom  work. Design has a lot to do with what materials one uses. Modern designs with sleek profiles are the most challenging because one cannot use bulky wood members for the framework. The framework is the most important part of the unit, since it determines its structural integrity. I have in modern looking windows designed frameworks out of rectangular aluminum channels which I had built and welded together by competent shops. I then in turn built the window sections to fit within ,and cladded all parts of the frame with wood some only actually being veneered on the interior. The end result was always a rigid unit with no flex whatsoever. 
 

Long units of traditional designs can be all out of wood unless extremely long in particular. If they are while single panes from top to bottom individual section can be made and screwed together as it is done with most commercially made units . Once together they will be rigid. The exception would be as stated before if separate units are on top. A long horizontal member of some type will be needed to be introduced between them to eliminate any flexing which will be inevitable there.  
 In my opinion only wood or metal should be used in any framework for windows of any given size. Any plastic material used will not have the necessary structural rigidity. Their rigidity will also be greatly reduced when exposed to higher temperatures . 

[squonk 41,118]

I have worked in more than 1 shop that had large metal framed, multi-section industrial windows that flexed like crazy when the wind blew during storms. I even saw them move by the sound waves of a idiot's car stereo bass notes when his car was parked outside. Scared the crap out of me.

 

[formariz 11,987]

18 minutes ago, squonk said:

I have worked in more than 1 shop that had large metal framed, multi-section industrial windows that flexed like crazy when the wind blew during storms. I even saw them move by the sound waves of a idiot's car stereo bass notes when his car was parked outside. Scared the crap out of me.

 

Anything will flex if it’s large enough. 
Windows you mention can not only be extremely large compared to a residential window, but are also usually thin in section seldom being more than 2-1/2” usually being made out of 1-1/2” square channel. 
 A residential window’s frame is usually as thick as the walls are . The largest one I ever built was about 6’tall by 12’ long. It had a 6” deep frame out of aluminum channel. It was basically a “wall”, larger than most windows . Not only it did not flex it could actually be used as a bearing wall. As for flexing along its length, possibly that could only happen around center of unit. I can assure you that under normal strong windy conditions that will not happen . Under a hurricane however one has not only to worry about the window but also the whole house.
 

[Tractorhead 9,064]

Hi cas,

 

I agree with you, a real assessment is actually only possible if you know how it is structured.

my own experiences been 15 years ago.

 

I only know windows of this type of Plastic Framesets - with several individual windows - in an overall frame from profiles that are plugged together. At least that's how they do it here, but that can also vary from manufacturer to manufacturer.

i dunno each manufacturer, i just seen 3 Company differences and only one built a metalstrucure inside.

They started at a width of 1,80m to insert a steelpipe

- ok steelpipe sounds funny by a 0,5 mm thick metalprofile that is inserted into the Plasticframe -

This can also being bended, not that strong an the non metal types but it can.

with the better Manufacturer Windowframe you was able to bend it at about 12mm on a 3m with

The cheaper ones beds up to 2-3cm in this lenght.

 

The Bending also depends on how the Framesets beeing mounted into the house Structure and how good the Workers established the Ancors in the Structure of the House.

good Wokers they set the ancors on best places can drop the bending down to less than 1cm,

some others results in up to 2-3cm bending.

 

Depending on the thickness of the Frame profiles and the type of plug-in connections and how they be made.
These sections are mostly then glued together so that the scaffolding is portable.

another big difference was the plugging system and how they solved it.

 

But even when carrying such scaffolding, we often had to frame the whole thing with two thick wooden boards so that it didn't sway back and forth while transport to destination.

 

Here it also depends on where the window was bought.

The typical hardware store windows here are mostly second choice.

 

But as allready mentioned my experiences been more as 15 years ago.

Edited September 1, 2023 by Tractorhead

[Mickwhitt 4,624]

Hi all.  

 

It's a pretty standard uPVC framed window. Not very well designed or built in my humble opinion.

 

But I don't want to scrap it and buy a new one or reduce the size of my lovely big window.

 

So I've fabricated two separate bottom mountings and bonded these into the dwarf wall that is beneath the window.

I've cut and fitted two lengths of 40mm thick walled box section to run up the frames between the larger and smaller units.  Tomorrow I will make mounting tabs to weld on the upper end of the box sections, to anchor to the wooden joist above the window frame. 

 

Then we will see if the thing moves when I push against it. The only other thing I can think to do is make a horizontal box section to run behind the top glazing bar making essentially an H shaped subframe supporting the whole centre section of the window, but this might be overkill.

 

Mick 

[Stormin 9,981]

Just a thought, Mick. Maybe it's a good thing it flexes. Think trees. If trees didn't bend in the wind, we'd be inundated with firewood. 

[Mickwhitt 4,624]

I'm building in some degree of movement,  it won't be rock solid.

I just need to cut down the large movement in high wind.

I've basically turned one big window unit into three smaller ones, or that's the theory. One firm suggested stone mullions to spilt the window up which is pretty much what I'm doing but with steel. And it's not costing the earth to do. If it all goes wrong then I've not lost anything much, like Eddison said, I've not failed, just succeeded in finding another way that doesn't work. 

[Mickwhitt 4,624]

So. After a little more fabrication work the trial supports are in place. 

The lower anchors are bonded to the brickwork with a specialist adhesive, there are also steel legs that sit down between the brick leaves to support and pushing load.

The top brackets are just screwed into the heavy wooden joist across the window reveal.

The plate is long and offset as I had to find a place where each leg would slide easily into the wall cavity.

 

Top brackets are just long tabs with number six woodscrews. 

 

The inside shows how the steel support frame sits snug against the plastic window profile.

from outside the windows are now nice and flat, they had adopted a bowed in look from the constant wind pressure. Just fitting the supports has pulled things back into place.

I can lean full weight against the centre window and it doesn't move. 

let's see what the autumn winds bring, it will either be success or looking for a whole new window. 

[Mickwhitt 4,624]

I'm at the final fit before trial stage.

 

Bracing sections are painted a rough match and bolted in place.

 

I'm not doing decorating bit just yet as things may need tweaking in the first big wind.

 

But here are a couple of videos that show The flex before and after the bracing rods are bolted in. 

 

 

 

[Tractorhead 9,064]

Whow great improvement !

 

again a short video tells allway’s more than a 1000 words.

 

I missinterpreted your description a little.

I thought you mean with the windload movement the moving after your improvements in the middlesection of the complete Frameset

that is what i see as „ normal“ but when i see the first movement of the frameset close to the border before your improvements that would scares me also.

 

How much be your Handpressure on the Frameset - i guess about 5-10 Kilos.

With that little pressure that movings is a no go.

On higher Windloads like on Stormy winds the Frameset will shure move, 

but not that strong as you showed in the first vid.

 

 

[formariz 11,987]

Wow. That was insane movement. I see now how it would be scary in a windy day. I have never seen anything like that. Still a bit much movement but a great improvement. 

[Mickwhitt 4,624]

Wow Caz, you think it still moves too much? Still some room for improvement then, or do I say that's the flex I designed in lol.

 

Yes Tractorhead, I was only pushing pretty lightly in the video. I know it was kind of a point load rather than across the whole frameset but it showed the kind of movement we've been having. 

 

I'm pretty confident this fix will be a long term solution until.the window needs replacing,  but that probably won't be until after my expiry date. 

 

Thank you to all who gave their thoughts and comments on my problem. I will update it when the winds arrive.

 

We have thunder storms forecast for today but no wind to speak of. 

 

Mick 

[Tractorhead 9,064]

Did you just set the improvement from outside or both sides?