Refurbish or replace UPVC bay window?

[Sparrowhawk]

Our house has south facing UPVC double-glazed bay windows in one room upstairs and downstairs. I'm looking for advice for what to do with them. We don't know the age of the windows but maybe 25 years old?

The frames are in fair condition, we had a locking mechanism replaced as it had rusted solid (coastal location) and bits are rusty but otherwise okay.

 

However, airtight they are not. The bubble gaskets on the opening windows no longer seal and I'm replacing those, which makes a noticeable difference.

And has made the air leaks around the glass panes more noticeable (marked by post-it notes above)

 

The windows face the prevailing wind and the mould in this one should've been a giveaway that air and moisture is coming through, even before I went round with a candle finding draughts.

 

 

Looking at the rubber seals around the glazing units they look worn down (for want a of a better phrase) and aren't angled up the glazing like they are on other, 20-year-old UPVC windows.

I suppose these draughts can be sorted by taking out the panes and replacing the rubber seals around them.

 

But then if removing the glazing, what about replacing it with new glazing units? They'll have better U-values and losing less heat out through the windows in winter would be good. I haven't got quotes so not sure what the costs are like.

 

And then the option that gets every double glazing company salivating. Full replacement. I know that's not going to be cheap but don't know the price jump from replacing units to replacing it all.

 

As brief background we're doing what we can to stop draughts and insulate, but it's never going to be passivhaus and as we live in it we can't strip it to a shell and rebuild. There is a cost balancing issue here e.g triple glazing would not make sense given the thermal inefficiency of the rest of the house, and replacing these windows probably wouldn't either. The north facing ones on the other side of the house, maybe have a better case.

 

What difference would replacing the glazing units make? Anyone done that and sourced them themselves?

Edited January 13, 2023 by Sparrowhawk

[MikeGrahamT21]

You’d definitely get a performance increase from what you have now (likely air filled DG with aluminium spacer) to (argon filled DG with plastic spacer), but glass prices are high at the moment.

 

Definitely replace the gaskets, adjust the locking mechanisms and take out any beading which has air leakage, it may have just been installed incorrectly (I found this on one of mine, a bit of packer was in the way preventing it from driving home), if the beading is damaged a local window firm should be able to get some, it looks like standard stuff to me, and after all that there’s window film which can achieve some of the low emissivity benefits, and that little lot shouldn’t cost too much.

 

also removing the trims and quadrants can uncover bad jobs which can easily be improved with a bit of time and effort.

 

a few of us on here have used this company, including me, their prices seem fair and you can play about on their website to get quotes without having to go all in…https://www.modernupvcwindows.co.uk

Edited January 13, 2023 by MikeGrahamT21

[Radian]

Have you considered using a UPVC gap filler like this? Worth a shot for the time being.

[RobLe]

These guys will sell U=1 planitherm DG units online - just make sure you measure up what you have accurately - wrong sized glass is useless!  25 yr old DG units are almost certainly U=2.6 ish, with a cold edge, and sadly there is no fix for that, but you can replace it:

https://www.sealedunitsonline.co.uk/

Well done for trying repairing, not just throwing away and buying new stuff though!

 

I replaced the DG units in our pvc frames 10 years ago with planitherm 1 DG units.  The frames are over 30 yr old now, all are still fine, plastic is good in the right place, terrible in the wrong place.  Better than fine - I drilled them in lots of places and injected foam insulation whrever possible - just be very careful not to fill any required drip path or airways cavities.

[gaz_moose]

id probably take each glazed unit out one at a time and clean the seals, then reassemble them with a smear of silicone on each one.

its easy enough to get them out, just hammer a gasket scraper between the beading and frame.

[Mr Punter]

They look pretty good to me.  Being 25 years old, south facing and with no units failed from misting up is quite an achievement.

 

I would not get too obsessive about sealing all draughts as I don't see any trickle vents and unless you have some other form of ventilation you may get more mould rather than less.

[Sparrowhawk]

Thanks all!

 

14 hours ago, MikeGrahamT21 said:

also removing the trims and quadrants can uncover bad jobs which can easily be improved with a bit of time and effort.

The trims and quadrants being the "strips of shame" between the window and the wall?

 

I removed a section in the autumn. Behind it was... the open cavity. With slivers of daylight visible around between the outer brickwork and window.

Instead of plastered window reveals we have the original half inch timber which was cut back when they installed the windows. My plan is to rip it off this year, close the cavity, seal the window to the new closing, and get a plasterer in to make good.

 

 

As you can see, 3 trims stacked on each other between the window sill and window!

 

13 hours ago, Radian said:

Have you considered using a UPVC gap filler like this? Worth a shot for the time being.

 

Would this go along the edge of the outer wedge gasket?

 

2 hours ago, RobLe said:

Well done for trying repairing, not just throwing away and buying new stuff though!

 

Thanks, jit seems such a waste (as well as unnecessary expense) when the UPVC is okay. And thanks for the link to replacement glazing, exactly what I wanted to see what it'd cost.

 

2 hours ago, RobLe said:

Better than fine - I drilled them in lots of places and injected foam insulation whrever possible - just be very careful not to fill any required drip path or airways cavities.

 

How would I find out which paths are required so as not to muck it up?  I drilled and filled the joint between a UPVC door frame and the abutted window with foam last winter as the extension had settled since it was built and the mastic pulled aprt, so (again) cold air came in through a half-mm gap up the join. Foaming that made a massive difference.

 

1 hour ago, gaz_moose said:

its easy enough to get them out, just hammer a gasket scraper between the beading and frame.

 

I was wondering how to get the beading out, so many thanks. Now to find a few YouTube videos and see this in action.

 

42 minutes ago, Mr Punter said:

I would not get too obsessive about sealing all draughts as I don't see any trickle vents and unless you have some other form of ventilation you may get more mould rather than less.

These windows regularly get hit by 40mph+ gusts throughout the winter months and these rooms are "breezy" - if I close the door out of them and put my hand under it, there's a stream of air. I can't wait to have to worry about ventilation

[Radian]

7 hours ago, Sparrowhawk said:

 

23 hours ago, Radian said:

Have you considered using a UPVC gap filler like this? Worth a shot for the time being.

 

Would this go along the edge of the outer wedge gasket?

I hadn't considered that. Is there a safe way you could put up a photo of the outside gasket? I don't understand what the issue is there.