Double Glazing or not?

[Phil Pascoe]

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.

The experienced fitter who put in my windows said if you buy triple glazing in this Country you've been conned. The frames will be for 28mm panels and therefore the gaps will be too small.

 

[ian33a]

The experienced fitter who put in my windows said if you buy triple glazing in this Country you've been conned. The frames will be for 28mm panels and therefore the gaps will be too small.

Not totally true , but largely so:

For triple glazing to be close to effective with an argon fill you will need 4-12-4-12-4 = 36mm. 28mm panels, I agree, are not effective. 36mm is the installation that we have in our house.

These were purchased before I became interested in glazing technology and we were sold this on the basis that it would reduce road traffic noise substantially and be much more efficient.

Since having these fitted and learning a huge amount , I have always said to customers who have expressed an interest in having their panes "upgraded to triple" (or, as I originally accidentally typed "tripe"!) that triple glazing in the UK is more of a marketing exercise than a real benefit. Here's why: firstly, the temperatures in the UK barely justify the need. Secondly, the overall unit sizes needs to be substantial to maintain decent U and this is almost never possible with an existing 4-20-4 make up. Thirdly, triple glazing doesn't substantially reduce noise but acoustic glass is what should be fitted to do the job properly and, finally (the big one), having been called out to replace misted up panes, triple glazed windows double the risk of a given pane failing because they come with two sets of seals and not one. From an installation/repair perspective, triple glazed units weigh 50% more than their double glazed half brothers and with large picture windows and even with smaller units, they can be really heavy!

Triple glazed units don't cost a whole lot more than double glazed units at wholesale price. The biggest cost is in the frames, fitting, commissions and contribution to the company operating expense. Consequently, the concept can be sold as a major (marketing) advantage while the cost increase is minimal. ... but people get sucked it. If I had my time again, I'd do my best to not have triple glazed units.

 

[TominDales]

If you do the calcs on energy saving and add long term maintenance/replacement DG generally not cost effective.
Has benefit of sound insulation.
Trad joinery properly with linseed oil paint well maintained lasts indefinitely, 100s of years etc

Glad to hear. We have regency sash windows, very thin wood, but with shutters that can close at night. They are in a need of a good coat of paint - I've not done it for 10 years upstairs as they are high up and was wondering about DG give the need for netzero.
The windows are a feature of our house, very large, give lots of light and the glass bows out - vauxhaul glass. Looking at old photos I'd estimate they are 100+ years old. thre are 18 of them, 4'' by 8'' and one is rotten, I probably need to get painting give what you have just said, or I'll be in trouble - its took me two summers last time! Probably need to get a specialist decorator in this time.
Not sure how to source the wood for the rotten frame. The original is a strong pine very straight and strong, can you get old pitch pine these days?. the shutters are amazing, very thin panels that are straight and true 8'' by 8'' sections, quite probably original from the 1800s

 

[sometimewoodworker]

For triple glazing to be close to effective with an argon fill you will need 4-12-4-12-4 = 36mm. 28mm panels, I agree, are not effective. 36mm is the installation that we have in our house.

That may work for heat insulation but is not as effective for sound insulation as say 4-12-3-12-5. All the glass being the same thickness is far less good that having different thicknesses as sound transmission is cut at different frequencies using different glass thickness.

We have managed a 24db + reduction by using good frames laminated glass on the outside (for security) and a different inner pane thickness.

I don’t have data on how the sound reduction would be changed if the laminated panes were also different thickness

 

[ian33a]

That may work for heat insulation but is not as effective for sound insulation as say 4-12-3-12-5. All the glass being the same thickness is far less good that having different thicknesses as sound transmission is cut at different frequencies using different glass thickness.

We have managed a 24db + reduction by using good frames laminated glass on the outside (for security) and a different inner pane thickness.

I don’t have data on how the sound reduction would be changed if the laminated panes were also different thickness

Exactly (I agree totally with you - acoustic glass mentioned in a previous post by me) , I was told that this make up would work by the salesman but later discovered that it isn't especially effective from a sound insulation perspective. Acoustic glass would have been the right way to go but the glass thicknesses would need to have been tuned to the noise that I would like to have eliminated. I have seen websites which provide examples of thicknesses to tune out, for example, road or train or aircraft noise. Generally what works for one, doesn't necessarily work well for another.

 

[TominDales]

'

Actually the interesting thing emerging is that it wasn't the lead, it was the linseed which gave the longevity.
Best window stuff is "unsorted" grade Swedish or Russian redwood. It is "sustainable" by virtue of replanting and relatively local compared to tropical hardwoods often from dubious sources
It's was just about the most common material for joinery past and present

I think this answers my previous question. Can you get a slow grown type of pine these days? I replaced the wood on our garden gate and garage doors that is probably only 20 years old as it was like balsa and rotted right through. Whereas the original house casements and wood supporting the cast iron gutters is still sound after 200 years.

 

[Jacob]

I think this answers my previous question. Can you get a slow grown type of pine these days? I replaced the wood on our garden gate and garage doors that is probably only 20 years old as it was like balsa and rotted right through. Whereas the original house casements and wood supporting the cast iron gutters is still sound after 200 years.

People blame the wood but its design and finish which are the problem.
Slowest growth is from further north and used to be named "Kara Sea pine", "Archangel pine" etc . "Unsorted" grade Swedish or Russian redwood are just as good as they were but you can't get the very wide boards which would have been from virgin forest.

 

[Phil Pascoe]

I replaced the wood on our garden gate and garage doors that is probably only 20 years old as it was like balsa and rotted right through. Whereas the original house casements and wood supporting the cast iron gutters is still sound after 200 years.

I stripped 100 years of paint from my fascias, drilling out all the old broken ironmongery (scores of pieces), filling the holes, soaking with cuprinol etc. The wood was fine except for the one piece I replaced ........... which was the one piece that had already been replaced. Twenty five years ago and it's still fine. One lesson I did learn (fortunately before I did that job) was not to sand the wood to too fine a finish, especially if it's never going to be looked at closely. I did these with forty grit and slightly rounded all the corners - the paint adheres so much better.

 

[Woody2Shoes]

Inward opening common in France - made possible by having tall narrow sashes which fold back into the window reveal and hence take up no space. They have outward openers too but as solid or slatted shutters un-glazed.

I think inward opening is mandatory in parts of Germany and Switzerland - so people can regularly clean their own windows (don't want anyone making the place look untidy do we?!)...

 

[Richard_C]

There's a lot of good points in this thread, but what about saleability?

We all have to sell up one day, or our heirs/executors do, or worse the local authority of you are intestate and have care bills.

When you sell, it's reasonable to assume that the buyer, valuer and surveyor they engage won't have the nuanced understanding like the people commenting here, they will just tick a box that says "DG - no" and advise buyer to negotiate the price down or look elsewhere.

At almost 70 I am realistic : I will be selling up my slightly too large and awkward house in about 10 years time *. Any work I do now has that in mind, conventional, good quality, easy care and saleable. (I'm not cynical, I'm not saying do it cheap but make it last 12 years si it's someone else's problem). Were I 35 and content to live where I do for a long time I might take different decisions.

So the DG or not question has a non technical, aesthetic, human, dimension. Only you can answer that bit.

* keep an eye on market place for lathe, Bandsaw and pillar drill sometime around 2030.

 

[Jacob]

.......

When you sell, it's reasonable to assume that the buyer, valuer and surveyor they engage won't have the nuanced understanding like the people commenting here, they will just tick a box that says "DG - no" and advise buyer to negotiate the price down or look elsewhere.
.......

You get the buyers to match.
Period detail is a big seller with some people and in general adds value.
I never ran out of work when I was doing sashes etc and got some very nice jobs. My various moves went well too with original or replica sashes.
It's a particular market and there are a lot of punters, believe me!

 

[Phil Pascoe]

Around me two very nice streets (the two nicest in the town, one of which I lived on) were considered years ago for making into conservation areas. There was a mad rush to install uPVC before it happened (ultimately it didn't, they realised too many properties had already been changed). Most of the Victorian box frame windows had already been replaced by post WW2 joinery that was crepe anyway, and of the hundreds of people I spoke to over twenty+ years no one was remotely interested in originality, they were interested only in the practicalities.

 

[ian33a]

Around me two very nice streets (the two nicest in the town, one of which I lived on) were considered years ago for making into conservation areas. There was a mad rush to install uPVC before it happened (ultimately it didn't, they realised too many properties had already been changed). Most of the Victorian box frame windows had already been replaced by post WW2 joinery that was crepe anyway, and of the hundreds of people I spoke to over twenty+ years no one was remotely interested in originality, they were interested only in the practicalities.

That's it : purists will pay. Most people want practicality and wont.

We're seriously considering moving next year. I'd love something original, characterful and dreamy. At my age I need something with kerb appeal but practical and easy and cheap to maintain.

 

[TominDales]

Around me two very nice streets (the two nicest in the town, one of which I lived on) were considered years ago for making into conservation areas. There was a mad rush to install uPVC before it happened (ultimately it didn't, they realised too many properties had already been changed). Most of the Victorian box frame windows had already been replaced by post WW2 joinery that was crepe anyway, and of the hundreds of people I spoke to over twenty+ years no one was remotely interested in originality, they were interested only in the practicalities.

Do you think that is still as-true today? Although the vast majority of people have busy lives especially trying to raise a family with modern burnt out jobs and long commutes. But there has been a huge rise in house prices over the years and a broadening of interest in property. Around us - I'm thinking Harrogate not so much Ripon the period theme seems to be the big sell. Probably still a minority, but quite a big and well healed one.

 

[KieranJW]

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.

 

[Jacob]

That's it : purists will pay. Most people want practicality and wont.

We're seriously considering moving next year. I'd love something original, characterful and dreamy. At my age I need something with kerb appeal but practical and easy and cheap to maintain.

Well one big advantage of the trad sash is ease of maintenance - everything can be done from inside the room - sashes themselves removed for painting but that's dead easy. Probably why so many old ones are still serviceable.

 

[KieranJW]

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

Thanks Ollie,
I too have used the polymer putty replacements too and quite like them especially if customer is using a standard paint.

I do know of a job where slim units were used and the supplier provided sovereigns silacryl to bed the units in and they failed. I have used silacryl as an acrylic caulk substitute or as a sealant but never as a bed.

I did wonder if bedding units with the putty replacements would help if the double glazed unit seals fail as you would effectively have a secondary seal.
I like this as I think it looks better than beads on more traditional windows.

There is a lot of food for thought.

 

[Phil Pascoe]

Do you think that is still as-true today? Although the vast majority of people have busy lives especially trying to raise a family with modern burnt out jobs and long commutes. But there has been a huge rise in house prices over the years and a broadening of interest in property. Around us - I'm thinking Harrogate not so much Ripon the period theme seems to be the big sell. Probably still a minority, but quite a big and well healed one.

I'm speaking of only 15 years ago. (A quite big and well heeled one?)

 

[Phil Pascoe]

Well one big advantage of the trad sash is ease of maintenance - everything can be done from inside the room - sashes themselves removed for painting but that's dead easy. Probably why so many old ones are still serviceable.

Yes, but it's quite labour intensive - few people want to do the job themselves. I've repaired badly damaged box frame windows that I could have made from scratch quicker. Builders and chippies around here work for £200 a day only if they're really desperate.

 

[KieranJW]

People blame the wood but its design and finish which are the problem.
Slowest growth is from further north and used to be named "Kara Sea pine", "Archangel pine" etc . "Unsorted" grade Swedish or Russian redwood are just as good as they were but you can't get the very wide boards which would have been from virgin forest.

I tend to only use the heart wood for exterior but I'm not sure if this is necessary it just reassures me as the durability tables are always based on heartwood and not sap wood which is generally far less durable. In the past we have used douglas fir too dependant on what the original joinery looks like it is made of. I have a friend who has been using pitch pine in repairs more recently. I also know someone who never uses softwood nowadays as he does very high class work so it is always hardwoods but when he did he tended to use larch.