Replace glazed units

[dishman]

Hello,

I have some 20 year old double glazed units. They were very good quality frames and units at the time.This has been reflected in their longevity as they are still in very good condition. As far as I can see none have failed or misted up as of yet.....

My question.....if any do fail....is it a simple process to just replace the glazing? ?

As far as I can see, they are externally beaded. Is there a major risk of the beading breaking or something else going wrong if at some point I do need to replaced a misted up pane.

I am loathed to replace a whole frame and units if a simple piece is at risk of snapping as I assume it will be impossible to get a replacement piece of beading 20 years later.

 

[ronniecabers]

Shouldn't be any issues, we replace sealed units all the time. You will either have a security tape , or a ' wedge ' gasket internally. If you can lift the internal black gasket with a flat bladed screwdriver , you will have wedge gasket and that will need to be removed before you can get the external beading off

 

[dishman]

Is the beading tougher than it looks?

I am just thinking 20+ year old beading = could be brittle.

 

[ronniecabers]

the upvc can become a little brittle , but in the 15 years i've been doing it , haven't broken a upvc bead yet.

They can bend quite well, if in doubt maybe warm up a little with a hairdryer....

 

[dishman]

As a further question, am I correct in thinking that if the glazed unit to be replaced has a smaller air gap, a modern unit is made to fit (same smaller air gap) without problem? Does this also include all the benefits of a modern glazed unit, warm spacer bars and the like?

 

[ronniecabers]

Sealed units can be made to you specifications ... so making a new sealed unit to the original spec will be no problem . Also , yes the new unit can be made with modern specs but if you are only doing one sealed unit then you will never get a gain from the better energy efficiency so therefore would be wasting the extra money it would cost.

 

[dishman]

Also , yes the new unit can be made with modern specs but if you are only doing one sealed unit then you will never get a gain from the better energy efficiency so therefore would be wasting the extra money it would cost.

This is true, but I was thinking more long term. If one has gone then the other may begin to go, so over a couple of years they may all end up getting replaced with a higher spec unit. At that point it may have been worth the extra effort...

 

[Gazman16]

Oops I wrote this yesterday but forgot to post it.

Couple of things extra just to think about and check.
You may also find security clips holding the glass in, These can be a pain to get out so check behind a few beads before you go ordering a whole load of units.

It may also be worth replacing the gaskets at the same time as they tend to shrink a bit. If the external ones have gaps at the corners replace them.
With the internal wedge gaskets (assuming this is what you have) I would replace them for security anyway, Quite often I practice with old windows that I'm taking out and 20 year+ old windows I can often take the beads out with no damage because the gaskets have shrunk/gone a bit soft.

Gasket is only about £1 per meter from ebay its just finding the correct ones that is a little tricky.

 

[dishman]

Gazman16 - a late follow up question.

I rang a local glazing firm with regard to an estimate for replacing the unit. They said in the absence of finding the correct gasket (which they would not attempt to do), their procedure was to use double sided tape and use silicone sealant (I assume the standard tube type).

Is this normal practice? It sounds a bit...quick fix as a solution.

I assume if the gaskets are fine then they can be reused but in your experience ( I don't see any gaps at the edges), what is the chance of matching a 20 year old gasket?

Also, do you recommend any time of beading removal knife. I see videos of pros using metal filling knifes/scraper things. In my mind plastic and metal do not mix well, especially with an amateur.

 

[Gazman16]

Assuming none have shrunk then they should survive ok and just reusing them is standard practice.
Personally on my own house I would want to replace the internal ones though for security as I mentioned before.

Alot of the gaskets are still pretty common today but it depends on the make of your windows some can be impossible to find too.

Have a go at removing a bit of the internal gasket. There will be a join in one of the corners so start there with a thin flat scraper and lever it out. You can put a thin bit of cardboard against the frame if you are worried about scratching it.

Once you have an end exposed take a photo of it and sketch/measure everything.
Then search this on ebay: wedge gasket sample pack
Find the closest one and order the sample pack, Try a bit of the sample in your windows and if it fits order as much as you need by the code.

For example
http://www.ebay.co.uk/itm/Sample-Pa...809405?hash=item4d08b8c83d:g:KrAAAOxyYANTa4dM

If you have new gasket there ready for them they should be happy to fit it for you

 

[dishman]

Here are some images. The wedge gaskets do not look too bad to be honest. Just need a good clean (best non-solvent cleaner?). All seem to have avoided any significant shrinkage so they may be OK for re-use. I have attempted at some measurements of the gaskets. I will have a look on ebay at the dimensions diagrams and order a sample pack. Any thoughts would be welcome.

 

[ronniecabers]

I think those gaskets look fine , I'd be happy to re use those, as for cleaning , soak them in a washing up liquid solution , it should loosen the grime and then wipe off...

 

[dishman]

Thank you for the suggestion. I have however read on many websites that washing up liquid should not be used as it contains solvents that will/can break down the synthetic rubber and also leave it a bit tacky (as in sticky).

I have come across a solution though...Autoglym Vinyl and Rubber cleaner! What is good enough for car gaskets and seals I assume should be just as good/suitable for windows gaskets.

 

[dishman]

Just to revive a previous question.

If I were to ask for pilkington K glass, how much extra would this normally add to the cost. The pane I am looking at is 558mm x 1137mm.

 

[Gazman16]

£5-10 although I would ask for Planitherm rather than Pilkington. Also go for black warm edge spacers (again another £5-10) but really makes a difference if you will be working your way through your windows.