Replacing double glazed unit in window frame

earnest · Friday at 13:59

Hello everyone, I am planning to replace the double glazing unit in the upvc/pvc window frame.

I would greatly appreciate if someone can help with these questions

Does this look like it was properly sized? How do I go about the spacers?

Would I measure the unit and order the exact same size? What is the best practice when replacing these please?

Can I replace with a triple glazed unit?

Thanks in advance.

HOJ · Friday at 18:30

earnest said:
Does this look like it was properly sized? How do I go about the spacers?

earnest said:
Would I measure the unit and order the exact same size? What is the best practice when replacing these please?

I always take 5mm off the tight size all round for my units, so, 10mm smaller in height and width, so as to get the right sight lines, you don't really want to see the spacer bar past the beads or in your case the edge tape, so I would use the unit you have as a guide to the sizing, or take the whole thing to the glass supplier if your not sure.

Then hence the need for spacers, they create a space around the unit, this will allow any water/moisture to drain/vent away rather than be in direct contact with the edge of the unit, leading to early breakdown, and also give you the option to be able to heel and toe the glass into the casement, and square it up, which, from my experience with UPVC ones, is best done with the casement in the frame aperture to make sure it fits properly, you can be brutal with the spacers if needs be to make it fit nicely, worth picking up a plastic glazing shovel to help do that.

earnest said:
Can I replace with a triple glazed unit?

Presuming the existing unit is 24mm thick, most triple glazed ones are at least 28mm + so no.

Lons · Friday at 20:52

100% what HOJ said on all counts. Unless you can find a triple glazed unit with overall thickness of 24mm which is highly unlikely, or change the beads you're stuck. They weren't available when I used to buy but that was a good few years ago and in fact I can't remember 28mm being available then as my memory suggests they were 36mm. Worth asking a glazier though as you never know.

To double check I'd suggest you accurately measure the thickness of your existing unit. Most likely as said it's 24mm but 28mm wasn't unheard of, depending on type of glass and yours being leaded might have made a difference.