Cutting Holes in Glass

~ for cat flaps, dog flaps, vents and extractors:

Fitting a cat flap in double-glazed unit We are often asked if we can cut holes in glass suitable for the fitting of cat or dog flaps, gas vents and fan extractors. The simple answer is yes, in most cases we can. However, this is determined by the nature of the job and the type of glass to be cut. Obviously plain (float) glass is the easiest to cut and can often be done with the glass in situ, but some jobs may require the glass to be replaced with toughened or safety glass to meet safety regulations.

Here is a brief guide to what can and can't be done, but if you are in doubt or you have any questions, please contact us and we will be happy to help.

Cutting Holes in GlassSingle Pane Window Glass, non-toughened (float glass)

This is a fairly simple process and can normally be in done with the existing glass remaining in place*. Only suitable for lightweight jobs such as fitting a small air ventilator.

Toughened Glass, mainly doors & critical areas.

The only solution is to have the toughened glass replaced with a hole already professionally cut into it.

Safety Glass, Laminated Glass & Wired Glass

The best solution is usually to have the glass replaced with the hole cut in.

Although this can often be done with the existing glass remaining in place*, it is a fairly high-risk process and can result in breakages.

Doubled Glazed Sealed Glass Units

Whether this is to fit a cat/dog flap, vent, or extractor fan, the only solution here is to have the sealed unit replaced with the desired hole cut into it.

It is not cost effective to try to strip the existing unit down and cut a hole, and is definitely NOT a DIY project to attempt yourself!


* On rare occasions, these techniques can result in breakage of the glass due to weaknesses or flaws. If this should happen the glass will need to be replaced at cost. Again - if in doubt please contact us for the best advice.

If you have any questions, want some advice or need to discuss a glazing repair, please use our enquiry form or call us on 0203 7594605


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