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Heritage glass slim double glazing


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Established Member
28 Aug 2016
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I have a customer insisting on using some double glazing from Heritage glass for a sash window, 14mm thick units.


I have never used the thin stuff and know Slimlite used to get bad press for unit failure, does anyone know if things have moved on and the modern stuff is better now?

It seems like you can bead it in or use the acrylic style putty in tubes, if anyone has used it what do they find the best method? I sometimes use the quick drying putty in tubes for glazing single glazed windows if it's a quick repair but it is awfully sticky to point.

I have expressed my concern at the glass but the customer wants to use it, they are supplying it themselves and agree that I am not responsible for any failures in the future.

Anyone use it on a regular basis who can reassure me it will be okay?

Thanks, Doug


Greatest Of All Time
29 Jul 2018
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I'm pretty sure the glass in our house is 14mm slimlite or something very similar, as far as I'm aware it's been in for over 25 years without issues. But then we've recently had a 12mm Krypton unit fail in a matter of weeks of being fitted on a job, on the fourth story, overlooking the sea... I think I'll wait until the weather's a bit better to replace it! :lol:

Look at it like this:

- Lower U-value than a regular 24mm unit
- Questionable longevity
- In most cases, twice the price

- Thinner than 24mm, but still a bit unsightly compared to true single pane.

In my opinion, it's a bit of a lipstick on a pig situation. Yes, it does look a bit better than a 24mm unit but it doesn't hide the fact that it's still a double glazed unit with the internal bars

As far as glazing the stuff goes, I believe you can use low modulus neutral curing silicone, linseed oil putty and synthetic putty which I've all used under advice from the manufacturer. The trick with the synthetic stuff (I use Timbaglaze) is to cut the nozzle so that it lays pretty much the perfect bead right off the gun and then tidy up the corners with a knife, don't get carried away and only do one pane at a time otherwise it starts to go off quite quickly and you'll never get it all tidy in time, don't ask me how I know that :oops:

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