Glazing units breaking down in hardwood frames

[MattS3]

We've got hardwood double glazed window frames, but after 20 years, there are quite a few which have started to mist over and break down.
Are they worth fixing or is a upvc unit a potentially better way to go?

[PoleDriver]

Mine have been in 10 years and 1 is starting to go. They can be replaced (simple DIY) but my landlord has decided to change them all for uPVC.

[mondeoman]

Ah the great double glazing con. pay xx thousands for windows to save x hundred per year in bills, but forget that your xx thousands has to be paid every 10-15 years and will never actually achieve payback.

[Pcot]

My upvc windows were installed 20yrs ago.
Not one glass unit has failed, and they have been totally maintenance free.
There is, and always has been a lot of cheap crap on the market in the window industry.
Pay decent money, and you'll get a decent product, that'll last for many years.

[Simpo Two]

mondeoman said:

Ah the great double glazing con. pay xx thousands for windows to save x hundred per year in bills, but forget that your xx thousands has to be paid every 10-15 years and will never actually achieve payback.

Maybe so but you still get better soundproofing/fewer draughts/more pleasant house.

You can replace just the sealed units of course.

[Renovation]

Pcot said:

Pay decent money, and you'll get a decent product, that'll last for many years.

Unfortunately the price you pay has little to do with the quality you receive IMO.

I was told units are more likely to break down if they are poorly supported when fitted - I'm unsure if this is true but sounds possible.

[Sheepshanks]

The rear of our house faces south-west and most of the units (in uPVC) failed after 10 years. Replaced the sealed units only from a well regarded local supplier, and, 10 yrs later they're starting to fail again.

The NE facing front has been fine apart from one large window which failed.

I'm told this is pretty normal, and indeed some neighbours have the same failure rate as me yet others haven't had a single failure.

[Trevor450]

A lot of mine are shot too. I understand it is more likely to happen in wooden frames than upvc due to the lack of drainage from the glazing beads.

I'm going to get mine redone by just getting new sealed units as the frames (1980s) are rot free and good quality.

There are a couple of places online that do various sizes of spacer to suit timber windows (narrow spacer) and the prices are cheaper than I thought.

I a, going to get a local glazing firm to quote first though as I have 38 units on the front of the house alone. Not all of them have blown (probably half have) but they are leaded which ruins the lovely views we have and I want to get plain units.

[Wings]

Using the correct glazing silicone sealant and ensure units are sat on spacers. My hardwood windows have been in for 30 years, and only in the last couple years have units started to break down.

[MattS3]

Sheepshanks said:

The rear of our house faces south-west and most of the units (in uPVC) failed after 10 years. Replaced the sealed units only from a well regarded local supplier, and, 10 yrs later they're starting to fail again.

The NE facing front has been fine apart from one large window which failed.

It's interesting you should say about the direction they face.
None of the windows on the NE side have failed, only the ones on the SW

[Adrian-calsk]

Renovation said:

Unfortunately the price you pay has little to do with the quality you receive IMO.

I was told units are more likely to break down if they are poorly supported when fitted - I'm unsure if this is true but sounds possible.

My glazing units fail because they are badly supported, only the south facing ones though. The little triagle wedge things are not wide enough. it cost me £450 quid before the fitter told me the problem, most wedges have now been changed

[talkssense]

Every South facing unit in our house has failed in the 14 years since we moved in. That is 16 units in a big range of sizes.

Not a single unit on the other side has shown any problems.

On that basis if my house was rotated 90 degrees like the neighbours the unit would all be fine (his are) so I don't think it is entirely down to the quality of the window or the way it is fitted.

[ShiningWit]

It's movement and heat that breaks them which is why South facing are worse as there is more thermal movement and heat.
Wood is sometimes worse as not only does it move, but the unit is often bonded to it with the sealant so when it moves it pulls the unit apart, they can also be badly fitted of course.
The guarantee on a new unit is shockingly short, only around 5 yrs IIRC - if you can get one.

You can get in situ repairs done now:

https://www.youtube.com/watch?v=du-Fu2V4oVo

[darronwall]

we charge 60 per sq m to fit new units,they aint dear!

[Foppo]

mondeoman said:

Ah the great double glazing con. pay xx thousands for windows to save x hundred per year in bills, but forget that your xx thousands has to be paid every 10-15 years and will never actually achieve payback.

I don't know where you got the thousands from? A few double glazing windows needed replacing in our house.About 80 to hundred pounds per window.The plastic is still fine.The windows lasted about 13 years and started to steam up.

[V8 Animal]

ShiningWit said:

It's movement and heat that breaks them which is why South facing are worse as there is more thermal movement and heat.
Wood is sometimes worse as not only does it move, but the unit is often bonded to it with the sealant so when it moves it pulls the unit apart, they can also be badly fitted of course.
The guarantee on a new unit is shockingly short, only around 5 yrs IIRC - if you can get one.

You can get in situ repairs done now:

https://www.youtube.com/watch?v=du-Fu2V4oVo

This is correct.
Expansion and contraction on the glass pulls the seal apart due to excessive heat. South facing windows.