Advice needed on order of restoration work

[skier-hughes]

I thought Biff just made the frames and installed sealed unit double glazed panes. I amy be wrong

 

[biffvernon]

As I said, I'll make anything so long as it is made of oak (and glass).

Double glazing a la Romans tends to mist up when the sun shines on it. The heat, it's a little greenhouse, sucks any moisture out of the wood and this condenses on the relatively cold outer pane. It goes again when the sun goes down. Not a problem on north or shady windows or bathrooms so the Romans were OK. And then you can use all sorts of old and coloured glass.

I've got dg units in my own house that I put in 20 years ago and they're fine. I've got some others that misted up a few months after I put them in my conservatory, but not before that supplier went bankrupt. So far, nobody I've supplied a dg unit in an oak frame has complained that it's misted up.

They need to be well made in the first place - and I think that they generally are these days. And they mustn't be allowed to sit in a puddle. It's the same old breathability issue. The seals prevent water getting in but the surroundings have to be well drained / ventilated / made of breathable materials.

I absolutely don't have any trade secrets. There's far more windows needed in the world than I can make all by myself so I'd welcome telling other would-be joiners what I do.

 

[Ian Bond]

I thought Biff just made the frames and installed sealed unit double glazed panes. I amy be wrong

Possibly, but I seem to remember that Biff has also made some double glazed windows that incorporate hand made wobbly glass, which were not sealed units - I could be wrong here though?

 

[Penners]

hand made wobbly glass

If you want to glaze a window with glass that looks a bit wobbly and distorted - hence looks old - use horticultural glass. It's cheap too!

 

[Ian Bond]

Sorry Penner, I have to disagree with that one! The wobbles are parallel ripples and it looks awful in a period window. Almost as bad as sealed unit double glazing!

 

[biffvernon]

Those who know will recognize that this is a bit of a simplification, but there are (were) five types of glass. Each has its characteristics, pros and cons:

Crown glass is made by spinning a blob of hot glass till it forms a flat disc. The disc is cut up into small pieces for leaded lights or slightly larger pieces for ‘Georgian’ small paned windows. Concentric ripples can sometimes be seen. There’s a ‘bulls eye’ left in the middle that was usually re-melted but sometimes used for low status locations such as pantries. Nobody makes crown glass anymore so it is irreplaceable.

Cylinder glass is mouth-blown, a ball is formed, stretched into a cylinder, cut open and unrolled to form a sheet. It is the commonest 18th and 19th century window glass. Irregular ripples give a lively appearance. It is still made in Poland, Germany and France. It is the standard glass used for period property repairs. Costs about £80 per square metre.

Plate glass is cast on a flat plate and then polished. Very labour intensive this always produced the most expensive glass. It was used for mirrors and very high status buildings in the 19th century.

Drawn glass is made by drawing a sheet of glass up from the melt through rollers. This was a late 19th century development and produced the bulk of window glass for the first 60 years of the 20th century. It is now available as ‘horticultural’ glass, mostly imported from Russia. Characterised by occasional horizontal ripples it is sometimes used for repairs in period properties and would be historically appropriate in late Victorian and early 20th century houses. At £10 per square metre it is an economically attractive alternative to cylinder glass.

Float glass, invented by Pilkingtons in 1956, rapidly came to be the dominant glass production method. Molten glass is floated on a bed of molten tin to produce a sheet with very flat surfaces and very constant thickness. It is now the standard window glass.

 

[Ian Bond]

Perhaps there are different grades of the horticultural glass - the stuff I've seen would best suit a greenhouse!

 

[Penners]

Ian - the horticultural I've used in the past has looked quite appropriate in a period window. Frankly, I think that any glass that isn't "perfect" does the job fairly well. It all depends how fussy you are!
:wink:
(Oops - I shall get into trouble with Moo for that.)

 

[Moo]

Now what on earth makes you think that, Penners? As a natural-born slut, fussiness is something I may aspire to, but haven't the energy or commitment to achieve. (So long as no-one draws a finger through it, the dust isn't really noticeable).

 

[Penners]

No - it was more the yellow measles that I was referring to, Moo.

 

[Ian Bond]

Ian - the horticultural I've used in the past has looked quite appropriate in a period window. Frankly, I think that any glass that isn't "perfect" does the job fairly well. It all depends how fussy you are!
:wink:
(Oops - I shall get into trouble with Moo for that.)

Fair enough, I must have been looking at some particularly bad glass - it had very obvious parallel ripples in it.

In fact, I am very fussy, and the amount of glass in my house is so small I'd probably save up to get the cylinder glass!!!

Or go extra posh, and pretend I've got polished plate glass (like some of the grand country houses) but use ordinary float glass instead

 

[biffvernon]

Or go extra posh, and pretend I've got polished plate glass (like some of the grand country houses) but use ordinary float glass instead

Ah, this is where it gets complicated as float and plate are not the same.

Before thrusting out my head, my senses, automatically active, had told me there was nothing there, that nothing intervened between me and out-of-doors, that the aperture of the window opening was utterly empty. I stretched forth my hand and felt a hard object, smooth and cool and flat, which my touch, out of its experience, told me to be glass. I looked again, but could see positively nothing.

"White quartzose sand," Paul rattled off, "sodic carbonate, slaked lime, cutlet, manganese peroxide--there you have it, the finest French plate glass, made by the great St. Gobain Company, who made the finest plate glass in the world, and this is the finest piece they ever made. It cost a king's ransom. But look at it. You can't see it. You don't know it's there till you run your head against it.

 

[Ian Bond]

Aye I know Biff. But I'd sooner use modern float glass than the corrugated effect horticultural glass.

Accidents happen, but luckily with small paned window you've only got a small piece of glass to replace, and less money to fork out.

 

[biffvernon]

You'll be wanting P1 from Tatra Glass then.

 

[Penners]

the finest French plate glass, made by the great St. Gobain Company

Saint Gobain still exists of course - a huge international building materials company turning over something like 40 billion euros. They still make glass - lots of different types of the stuff.

 

[Ian Bond]

Thanks for the Tatra link Biff!

Ian

 

[Penners]

If I remember rightly, I think Sting is an advocate of Tatric something-or-other isn't he?

 

[biffvernon]

Tantric. Have a word with Mrs P.

 

[Penners]

I will, but we're in the middle of something just now. Could take several hours.