I’ve a few cracked windows that need replacing on 100yr old sash windows.
The current glass is 2mm or 3mm on the ones I’ve measured. I suspect the 3mm ones were replacements.
Most places only do 4mm glass, but I can get hold of 3mm. 4mm would be stronger but might upset the balance of the sash weights. 3mm will be lighter but less durable.
What’s the best compromise?
4mm and add some extra washers to the weights?
I think it’s quite a big job getting to the weights.
There should be an access hatch but it might be well painted over. If its only a few panes I doubt it'll make much difference. Ours were super thin, not much over 1mm, really flexible. I've replaced with 3mm and they still seem to work OK but there is quite a lot of friction.
Yes, think I’ll just go for 3mm, if the 2mm stuff has lasted 120 years, it can’t be that bad.
Thought about putting slimline double glazing in them? Its sometimes possible if you get the rebates routered deeper or sometimes they just go in. Makes a significant difference. You do need to adjust the weights tho
If you can't access the hatches, you can just got long weights of varying sizes that just clip around the sash cord. Just pop down your local window specialist and ask for a long weight.
Are these six pane sashes? Larger Victorian panes are usually not that thin. It's actually not legal to fit thinner than 3mm to a sash anymore.
They are 2 pain sashes so fairly big
Just pop down your local window specialist and ask for a long weight.
That deserved more recognition.
Yep, the clip on weight is a good idea, but think I’ll just stick with 3mm, at least I know it will fit in the rebate. I don’t think 4mm is that much stronger anyway, suspect if you fell against it 3 or 4mm would shatter.
