Double glazing advice please

[rbel]

We have a very large double glazed single window (no casements or hoppers) which faces south west on to the rear garden and beyond. In very high winds the inner pane (and presumably the outer one) flexes visibly, which we have become used to over the years. The Valentine's day storms, which were more than a bit iffy at 160 metres up here on the south Devon coast, appear to have somehow flexed/moved the seals around the edges which seem to have allowed condensation into the void.

Before contacting glaziers I imagine that it that there is no diy solution to this problem?

If the only solution is a replacement unit, has double glazing moved on during the last 20 years, producing improvements that are real and cost effective improvements?

[Capitol]

As it faces southwest, you have a good chance that a couple of summer days will get rid of the condensation. I've seen this happen a few times. Alternatively you could remove the panel, drill a couple of holes in the seals and blow hot air through and see what happens!

[rbel]

Many thanks for the response.

Given some good weather does the condensation then stay away or is it likely to return as soon as the weather detiorates?

As the window is quite large, 2.5 x 1.6 metres, I think getting it out without several pairs of willing and skilled hands and the necessary kit may be a bit of a problem. I was think about carefully drilling a hole through the inner pane blowing hot air in and then bunging it up, but that is probably not feasible?

[Capitol]

My experience is that it stays away and doesn't recur unless the glazing rubber (External) allows water to lay under the sealed unit. ie the unit sits in a puddle. There should be drain holes under the glazed panel, but some fitters aren't too good at putting them in. Our units have been in for over 30 years and have always cleared.

[Brian Gaff]

In my old ones there is apparently silica gell at the side or bottom, but I still get condensation, but its been there since 74, so really cannot complain! Brian

[Roger Mills]

A Google is worth a punt. I found a few DIY solutions when I looked a couple of years ago, but haven't tried any of them.

Ideally, the unit needs to be removed so that you can drill through the metal spacer rather than through the glass. There's a risk of breaking the glass if you drill it - and a virtual certainty if it's toughened.

Either way, you need two holes at opposite corners so that you can circulate dry air through the unit. Some people suggest making a circuit consisting of the unit plus an air pump plus a box containing silica gel, which dries the air as it passes through.

Double glazing makers tell you that it won't work (they would say that, wouldn't they!) because the moisture will have stained the inside of the glass, and the stains will show even after removing the moisture.

I've got several panels in my conservatory which need some attention when I've accumulated a sufficient quantity of tuits! It's probably worth a punt if I can rig something up to do it.

[fred]

In article , rbel writes

Closed loop pumping of the unit air through desiccant seems a popular solution.

This article isn't the one I thought of when remembering this solution but it came up on a search and seems a good one, thanks to Max Cottrell for taking the time to write it up:

Article linked to at bottom of page.

One thing I'd be worried about in your exposed situation is the likely weakening of the inner pane by drilling it. Also, fair bit of the strength of DG units comes from the sharing of shocks between the inner and outer panes transmitted through the sealed gas so it would be a good idea to close the seal properly after you've finished so that the shock loading can still be shared and absorbed.

You don't mention the frame material, is there any chance you could set up a jig to slant drill into the back of the seals and into the spacer bars? I don't think you need to go all the way through as they are vented to the inside and will allow the passing of pumped air.

On the other page I saw this method suggested, the author left the desiccant pump running for a couple of days to make sure the unit was really dry (the desiccant may have been changed during the operation).

[harryagain]

The spacer bar between the sheets often is filled with a dessicant. You can tell if you have it, there will be a row of tiny holes in it that expose the dessicant to the air in between. With big sheets of glass, the seal soon fails due to differential expansion between inner and outer glasses. Worse if window faces South. The air gets in and for a while the dessicant "gets" the moisture. When it is expended you get condensation appearing.

There are firms that drill and change the air between sheets, dunno how long the cure lasts. But you can remove the sealed unit, take it to a glazier & they will make up another. Probably last a bit longer, they have better sealant nowadays. It will be very heavy, you really need to hire the sucker things and a few people to assist.

If you can see it flexing, you definately have a problem, they can use thicker glass, but more expensive and heavier. Consider low emmision glass.

[stuart noble]

I'd be thinking of having a SW facing (large) single pane replaced by something a bit more rigid, with at least one casement to break it up. Either that or I'd sit somewhere else when the wind was blowing

[rbel]

Many thanks for the suggestions.

The frame is uPVC but unfortunately it is located in a deep recess so getting at the edges, even with a right angle drill and slanting it, would not be possible without removing a fair sized chunk of blockwork each side.

[rbel]

Thanks for the very good detailed guidance - I will ponder further the problem of accessing the frame edges.

[rbel]

Until we got used to it the flexing was quite scary, but closing the blinds puts it out of mind and we always sit a safe distance from the window in question.

We are very lucky to have a splendid view from this window, out over the rear garden to the distant southern parts of Dartmoor. When we moved in the first act was to replace the existing, much smaller window, with this big panel to take advantage of the view. In retrospect the use of the original smaller window was understandable but we would be reluctant to detract from the view in any way.

I have been considering the installation of a roller shutter but the lack of a suitable space above the window seems to preclude this.

[sm_jamieson]

Sounds like a wonderful view. Any chance you could post a pic of the view through this picture window so we can share in your enjoyment ? There are several free photo sites where you can upload photos. Simon.

[Jonathan]

Can you attach it to the ceiling above the window? I have done this in the past.

Jonathan

[dennis]

If you look at the spacers you will see they are perforated. There is a desiccant (silica gel?) in them. If you have misting they are saturated and there must be a leak in the seal somewhere.

To fix them you must..

dry out the desiccant or replace. fix the leak maybe clean the glass or live with a stain.

You may be able to drill trough the edges of the seal and use some more desiccant to dry out the stuff in the spacers. It will probably take a long time and involve circulating dry air through the panel, possibly for days.

You might be able to scrape the desiccant out and replace it.

Then you need to tape it all around to fix the leak and reinstall it.

I think you would be better off getting it replaced, especially if it got broken by flying debris and you could claim on the insurance.

[Dave Liquorice]

Naw, our double glazed units flex in the wind 4-20-4 and about 2' x

3' nine panel georgian bars and spacers inside the units where the bars are on the outside. Decent bit of wind(*) and the gusts will have 'em flexing several mm. The old windows 3-6-3 and 5' x 3' would move over 1/2" in the middle, they had lasted 20+ years.

Mind you 2.5 x 1.6 m is a *big* window to have as one piece in an exposed location. Nice view or not...

(*) F8 Gale 40 mph and above sustained, gusts to 50 mph+. Most places don't experience anything like that sort of wind. The mown grass gets "combed", plants blown out of the ground and anything loose disappears...

[GMM]

Why do I suspect that a lot of misted dg panels will have suffered from storm damage recently? Almost wish I had some to replace......

I can confirm that it may not get better by itself though. I my last house, there was a pane that was a bit msited when we moved in. I sort of assumed that it might clear itself, as it got quite a lot of sun. By the time we had all the windows replaced a few years later, this one had nearly a foot of water in it. I never did work out why water could get in but not out.

[Dave Liquorice]

Comes in as vapour through very small holes. Condenses then can't get back out as a liquid through the same holes. Think Gortex. Air (and water vapour) are drawn in/pushed out due to heating and/or air pressure variations.

[Vir Campestris]

Let me scare you with this:

F8 you might get of the view is that nice. It's about 4 square metres, so you'll be getting about a kilonewton. Imagine a large fat man lying on it...

Andy

[Jim K]

/ Imagine a large fat man lying on it...

Andy/q

Clothed or naked?

Jim K