Double Glazing or not?

[Jacob]

I agree as the old conservatory on our house was one such dismal brown monstrosity and to add to its horror a polycarbonate roof. It was the first thing we changed after we bought it...yet I still got £100 for it on eBay!

I got given a brown monstrosity earlier this year. Luckily it was single glazed and I've recycled most of it into cold frames, firewood, etc.
Most of the wood was garbage but you can find some nice pieces in cr*p modern joinery which have got there by mistake - it's worth having a good look.
And horticultural glass is a good substitute for period glass - it often has a similar ripple - I've just put two pieces in the doors of a Victorian school cupboard I'm tidying up. All nice pitch pine which was under thick white gloss on old varnish like bonfire toffee.

 

[baldkev]

I got partway through page 2 and noticed there's 6 pages!

So i skipped 4 and a half

I have timber windows and dgu's in a house approximately 13 years old. The dgu's have just started to mist up ( most of them )

The windows however are utter rubbish! They have been painted twice since new and the windows on the most exposed face of the house still swell up. One major fubar from the manufacturer is that they used the foam glazing tape both inside and out, leading to the foam breaking down, the windows taking on water and the fixed sashes going mouldy!! I went round with silicone and carefully gunned it all in, which reduced our issues, but our neighbours properties, most of which have never had the woodwork painted, are falling apart.

I'll be replacing our windows, and, most likely, with a matching style in plastic.

I dont believe timber quality is the same as it was, its now grown and harvested quickly, processed as fast as they dare. Its also true that a lot of people dont keep on top of maintenance, which is half the problem

 

[Sandyn]

I get a bit on very cold days but have a condensation drip catcher in the cills, draining to the outside.

Would like to know how you do that? I was just thinking of doing something similar.

 

[sometimewoodworker]

Not even science is just logic. Keep all surfaces above dew point i.e. the temperature at which condensation will form. But not actually any help.
Frinstance if you boil a kettle the dew point temperature falls even as the temperature in the room rises.

humm. It is Physics, just because you consider it to be logic doesn’t stop it being science.

You are interpreting keep ‘all surfaces above the dew point‘ wrongly to be “keep them just above the dew point”. Of course you need to keep the humidity low enough and ventilation/circulation good enough so that normal activities like cooking and people breathing don’t cross the dew point for a considerable time.

While dropping under the dew point may instantly start dew forming (it probably won’t) a rise above it with reasonable circulation will evaporate a tiny amount before it becomes noticeable.

In certain conditions it is highly probable

Of course it is. That is why you design to avoid those conditions.

If your walls aren't as cold as your windows you will get condensation on the windows, if conditions are right for condensation

Of course they will. That is why you design to avoid those conditions.

Well it's a mystery to me that we don't have a condensation problem here, single glazed throughout some of it down to 3mm!
Sometimes see the odd patch on a cold morning but it's gone by the time I've made a cup of tea.

It however isn’t a mystery but physics. The humidity in your house is low enough that the air circulation/ventilation will evaporate the condensation.

 

[KieranJW]

Not even science is just logic. Keep all surfaces above dew point i.e. the temperature at which condensation will form. But not actually any help.
Frinstance if you boil a kettle the dew point temperature falls even as the temperature in the room rises.

Dessicants in DG unit are pointless - if the thing leaks it will slightly delay the point where you get condensation within, but won't stop it.

Yeah sorry the idea of dessicant was to remove any moisture originally trapped inbetween when sealed. I thought the spacer bars have a dessicant in the for similar reason.

 

[KieranJW]

I may have misunderstood what you are saying here Kieran but just to re-iterate that if you are fitting new frames you can't fit single glazing. Unless you are Fensa registered you must notify Building Control. I would advise against not doing this as a nosey neighbour could dob you in (I speak from bitter and ultimately expensive experience here) the rules are explained here Building Regulations | Doors and windows | Planning Portal

Our 19th century community pub (owned by the village) needs new front windows and the local company we have asked in to quote are recommending replacing the frames with Accoya Wooden windows, external wooden doors, timber windows, window frames (accoya.com) fitted with 12mm DG heritage glass. The existing frames are softwood and despite shelling out for rot to be replaced over the years they now need replacing; also the singe glazing causes really bad condensation in winter.

Thanks I have a customer.er who has managed to get permission for single glazing on a new property despite the original plans being for double glazing. I am more interested in having double glazing in some form if I can reduce/eliminate the failures I see with double glazed units. I will incorporate easier maintenance or replacement options I to the design I have been really pleased with all the relies and has given me a lot of food for thought. The main reason for the single glazing mention is that I know there is very little to go wrong but if I can achieve the same with double glazing in whatever form then I would go for that.

Be careful with the 12mm stuff as it can be prone to failure. I agree with Jacob on the linseed so if I was you I would look at that as a paint system I do quite a number of repairs on old windows and a properly executed repair should last and all joints or spliced should be design to shed water should any glue fail. As many people have said about the double glazing industry being full of misinformation ; this definitely applies to woodworking and heritage work. It is difficult to sift through marketing claims or old accepted methods that have come into general practice to only decades later realise how erroneous the advice was.

I often think that we have lost a lot of knowledge around effective building as when you think older methods all used more natural products effectively so that when no longer used could be repurposed if necessary. Stone and lime could be reused, linseed nourished and protected timber, turpentine would work as a pesticide, cob was an effective insulator both against heat and cold. Stockholm tar as a preservative. Interestingly they also often had many other uses too. These seem to have a much more circular life cycle so the waste either rotted down or could be reused. The problem I have found is that it is now actually quite hard to get a good education in these methods.

I am hoping that accoya proves to be as good as is claimed as we have fitted some doors and windows for a customer who had decided that it was the way to go and it hasn't proven to be as stable as is claimed. We didn't manufacture them and the dont seem to be a problem but they are definitely not quite as good as the marketing claims. I suppose I struggle with the idea of taking poor timber and treating it. I think better to get good timber and further improve it.

So, if you can see, I like to do things properly with-in the knowledge that I have at the time. If I am proven to be mistaken in the long term I can accept that as long as I had tried to fully understand what I am doing.

 

[Phil Pascoe]

A lot of buyers are looking for period quality. It's increasingly valuable. You don't know what you've got til it's gone

I lived on a half a mile long street of very nice Victorian Houses for 20+ years - in that time vitually every house had the wooden windows removed and replaced with uPVC (one or two with aluminium). Increasingly valuable? I would seriously query that in an average Victorian house. Most had windows changed immediately upon changing hands.

 

[Phil Pascoe]

Stockholm tar as a preservative? The only thing I knew it preserved is hen's arrrrses.

 

[johnnyb]

I've no idea on cost. but a single window I reckon 1/2 day.

 

[johnnyb]

Stockholm tar was the only preservative available for ships ropes for centuries. I think they use it to keep flies off hens buttocks.

 

[Jacob]

....

I dont believe timber quality is the same as it was, its now grown and harvested quickly, processed as fast as they dare. Its also true that a lot of people dont keep on top of maintenance, which is half the problem

It's not the timber it's the design details and cr*p modern paint. And the DG inits would have failed anyway.

 

[Jacob]

Woke this morning with condensation on most of my windows.
You get it most this time of year - equinoctial changes of warm damp air suddenly being cooled surfaces as nights grow longer. Less so as winter advances as the absolute humidity levels fall.
Is this a problem?
No, it's a solution - windows working as de-humidifiers resulting in a dry house. It will all be gone as the day warms up and any great surplus will drip into the condensation catching cilll design and be drained off to the outside. This was one of the great strengths of the traditional sash.

 

[Jacob]

[

Would like to know how you do that? I was just thinking of doing something similar.

It used to be common in public buildings like churches, chapels, meeting rooms. There'd be a little gutter in the cill formed one way or another and drained to the outside. In my building (ex chapel) the gutter was a little groove in the stone cill at base of each window, like a drip groove, full width, with 1/2" lead pipe connected at the middle, working as a drain. Just 6" pipe length to the outside with 1/2" an inch visible which you'd hardly notice.
Very simple, very effective. It would have been essential on a cold day if 300 people had been in, all belting out "Rock of Ages" at the tops of their voices.
I've replaced the windows with replicas and instead of using the stone runnel have incorporated a wooden one with 10mm copper pipe taking the water off. Can be seen dripping outside and on very cold days with little icicles.
If you look around old buildings you often see these details but the use has been forgotten and they may be sealed up, painted over, etc.
Sash windows wouldn't need this as they drain through the meeting rail gap or the bottom sash to bottom staff bead gap. Sometimes you encounter a beefed up bottom staff bead with a bevel which is intended as a drip catcher and also as a draught redirector when the window is open just half an inch or so

 

[Jacob]

.... You'd be lucky now finding softwood that would last 150 months let alone 150 years.

It's not the wood's fault its the design/details and cr*p modern paint.

 

[Doug71]

@KieranJW I would be surprised if a new build could have single glazing.

You said in an earlier post they went back to planning and got the DG changed to SG. Planning and building control are very different, In the past I have had unhappy people bring me windows to alter because planning said they could have them but the windows haven't complied with building regs for escape or toughened glazing etc.

Sorry if I'm stating the obvious but might be worth checking.

 

[Phil Pascoe]

Stockholm tar was the only preservative available for ships ropes for centuries. I think they use it to keep flies off hens buttocks.

It helps prevent other hens feather pecking. Once they draw blood they will likely carry on until they eviscerate the victim.

 

[Ollie78]

Does the Spacia glass still have the little cover cap on it? I have customers moan about the stamp to show that glass is toughened so don't know what they would think to the little cap on each pane.

Have them do what's called a furniture stamp it's tiny and sits under the sightline.

I am interested in the vacuum units, I have seen them being advertised but never seen one in real life.

Can't understand why anyone would get single glazing on purpose, even taking the trouble to go and get permission for it !
I often make double glazed stuff for old buildings, you can't tell until you get right next to them.

A note on the seals breaking down, I use hybrid polymer with full encapsulation of the units. Bedding and facing them, it looks just like a traditional putty line. This method is pretty reliable and I think better than beading, which is more likely to allow water and air to get in contact with the edge of the units over time.

This is an interesting thread about all the different glazing solutions.
If money was no object I think I would get the Internorm timber and aluminium ones with blinds built in to the units and the extra openable third glazing layer.
Properly engineered stuff, and toasty warm.

Given gas prices have gone mental I think any reduction in energy loss will pay for itself even quicker now.

Ollie

 

[GregW]

what about triple glazing....?.
I believe the Skandies have been using that for years...

It’s good for temperature below -20. Tested, customer not seen big difference in temperature resistance in that climate, however he told that lorries can be heard from direction of double glazing, not from direction of triple glazed main road.

 

[Sandyn]

If you look around old buildings you often see these details but the use has been forgotten and they may be sealed up, painted over, etc.

Now that you describe how it's done, I have seen that. It helps when it's designed in when the building was constructed. I thought you had devised a cunning method of doing it on a more modern build. I was trying to think of a reliable way of doing it.

 

[Jacob]

.... I thought you had devised a cunning method of doing it on a more modern build. ....

I have, but it's not very cunning. I'll do a photo later