perspex / polycarbonate glazing

8 Aug 2011
Reaction score
United Kingdom
Hi all im after some knowledge from those in the know! I rebuilt a double glazed unit last year with perspex instead of glass (outbuilding so it wasnt critical) and not only did it work well but it was much warmer!

Now my question is can i take a normal double glazed unit and bond a sheet of clear perspex on the out side of the frame so the unit goes glass gap glass gap perspex. I am thinking by placing the perspex on the outside of the unit it should keep all sides of the glass at fairly equal temperatures reducing the risk of thermal cracking?

So has it been done before? is it doable without damage or just asking for trouble?

Thanks for you time
Sponsored Links
I don't think it will crack. It won't look very nice though, I certainly wouldn't want sheets of perspex bonded to my windows. Won't you see the glue marks? :unsure:
Acrylics (Perspex, etc) are al very well but they are much softer than glass, more liable to be damaged by impact and they mark (scratch) much more easily
looks arent an issue as ive got lots of upvc trim kicking around so il silicone it in place and then trim the edges so you cant see the bond.
Scratches aren't a major issue we live in a 3 storey town house and both ends of the house on all 3 floors are floor to ceiling upvc and windows so they loose massssive amounts of heat and due to the size of the units upgrading them is out of the question.

Just didnt want to save £100 on gas to crack £1000 worth of glass :LOL: :rolleyes:
Sponsored Links
if the windows are relatively new and draught free another layer will make little or no difference

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local