Which cat flaps can be installed in double glazing glass in UPVC doors?
Cat Flaps for Glass Doors
Yes, a cat flap can be fitted into a glass door, but in most cases, the existing glass cannot simply be cut. If your door has toughened or double-glazed glass, the usual method is to order a new glass unit made with the correct circular hole for the cat flap.
At Catflaps.co.uk, we supply glass-fitting cat flaps, microchip cat flaps with glass adaptors, and manual glass cat flaps for use in doors, patio doors and suitable glazed panels.
Can You Put a Cat Flap in a Glass Door?
Yes, but it depends on the type of glass. Single glazing may sometimes be cut by a glazier, but most modern doors use toughened or double-glazed safety glass. Toughened glass cannot normally be cut after manufacture, so a replacement glass unit is usually required.
The new glass panel is manufactured with a pre-cut hole to suit the chosen cat flap or adaptor. This is why it is important to choose the cat flap first, then give the correct hole size to the glass company.
The Short Answer
- Existing toughened glass: usually cannot be cut.
- Double glazing: usually needs a new sealed unit with a pre-cut hole.
- Single glazing: may be cut by a professional glazier.
- Sliding patio doors: possible, but larger glass panels can make replacement more expensive.
- Choose the cat flap or pet door you want to use.
- Check the required glass hole diameter for that model.
- Measure the existing glass unit: height, width and thickness.
- Order a new double-glazed unit with the correct pre-cut hole.
- Fit the new glass unit into the door or window frame.
- Install the cat flap into the prepared glass opening.
- Check whether your glass is single, double glazed, toughened or laminated.
- Choose the cat flap before ordering replacement glass.
- Confirm the required circular hole diameter.
- Measure the glass unit height, width and thickness.
- Make sure the cat flap and adaptor will sit clear of the glazing beads.
- Use a professional glazier for glass measurement and replacement where needed.
- Microchip cat flaps often need a glass mounting adaptor.
How Cat Flaps Are Fitted into Double Glazing
Common double-glazed unit thicknesses include 20mm, 24mm and 28mm, although other sizes are possible. Triple glazing may be thicker, so always check the unit depth before ordering.
Choosing the Right Cat Flap for Glass
Microchip Cat Flaps for Glass
Microchip cat flaps are ideal if you want to stop stray or neighbouring cats from entering your home. They read your cat’s existing microchip and only unlock for registered pets. When fitted into glass, they usually require a compatible glass adaptor.
Manual Cat Flaps for Glass
Manual glass-fitting cat flaps are a simple, lower-cost option where selective entry is not needed. They are suitable for cats that simply need controlled access in and out of the home.
Large Cat Flaps and Small Dog Doors
Some larger glass-fitting pet doors are suitable for bigger cats or small dogs. Before ordering, check both the flap opening size and the glass hole diameter required.
Cat Flap Glass Hole Sizes
Different cat flaps need different hole sizes. For example, some glass-fitting cat flaps require a smaller circular cut-out, while microchip models with adaptors may need a larger hole. Always use the manufacturer’s stated hole size for the exact product you are buying.
If you are replacing glass, do not guess the hole size. Choose the cat flap first, then give the correct specification to your glazier or glass supplier.
Can You Fit a Cat Flap into an Existing Patio Door?
Yes, but if the patio door uses toughened or double-glazed glass, the existing panel will normally need to be replaced. Sliding patio door panels are often larger than standard door glass, so the replacement unit may cost more than a small glazed panel.
Alternative Option: Replace the Lower Glass with a UPVC Panel
If your door has a lower glass panel, another option is to replace that section with a UPVC panel and fit the cat flap into the panel instead. This can be simpler and may reduce cost, especially where a full glass replacement would be expensive.
Before You Order
Frequently Asked Questions
Can I cut a hole in my existing double-glazed door?
Usually no. Most double-glazed door panels use toughened safety glass, which cannot normally be cut after manufacture. A new double-glazed unit with a pre-cut hole is usually required.
Can a microchip cat flap go in glass?
Yes, many microchip cat flaps can be fitted into glass when used with the correct glass adaptor and a correctly sized hole in the glass unit.
Do I need to buy the cat flap before ordering the glass?
Yes. The glass company needs the correct hole diameter for the exact cat flap or adaptor being fitted.
Can a cat flap be fitted into a sliding patio door?
Yes, but the glass panel will normally need to be replaced if it is toughened or double glazed. Larger patio panels can make the replacement more expensive.
Is a UPVC panel easier than glass?
Often, yes. If the lower section of the door can be changed from glass to UPVC panel, fitting the cat flap may be simpler and cheaper.
Shop Cat Flaps for Glass Doors
Browse our range of glass-fitting cat flaps below, including manual cat flaps, microchip cat flaps with glass adaptors and larger pet doors suitable for selected glass installations. If you are unsure which product is right for your glass door, call our team before ordering.
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