Can You Put a Dog Flap in a Glass Door? (UK Guide 2026)

Yes, you can put a dog flap in a glass door. The process is identical to fitting a cat flap: a brand-new toughened glass panel is manufactured with the dog-flap aperture pre-cut, then fitted into your existing door frame. The existing glass is not cut on-site — it can't be, because toughened glass shatters when drilled or scored.

Dog flaps need a larger opening than cat flaps, so the glass panel must be measured precisely to ensure the hole doesn't compromise the structural integrity of the unit. We fit dog flaps into patio doors, French doors, bi-fold fixed panels and glass side panels across the North West, Cheshire, Staffordshire and North Wales.

Not every dog door is suitable for glass. The main brands we install:

• Pet-Tek G-SDDB / G-SDDL — purpose-built for glass. Transparent, circular, high-impact polycarbonate. The G-SDDB suits medium dogs; the G-SDDL fits large breeds. Because Pet-Tek is designed for glass from the ground up, the round aperture distributes stress evenly through the pane.

• SureFlap Microchip Pet Door — a larger version of the standard microchip cat flap. Rectangular opening (178mm × 170mm), so it needs a more carefully engineered glass panel. We fit these regularly into glass but the panel specification is stricter.

• Dogwalk (now Pet-Tek) — older Dogwalk units were also glass-specific and round-profile. If you have an existing Dogwalk we can replace it with a modern Pet-Tek equivalent.

For most dog owners, Pet-Tek is the recommended choice for glass doors because it's designed for the job, transparent (so it doesn't block light), and available in sizes that suit everything from terriers to Labradors.

The process is straightforward but specialist:

1. Measure. We take exact dimensions of your existing glass unit — width, height, thickness, and whether it's single, double or triple glazed. We also measure your dog's shoulder height and width to specify the right flap size.

2. Manufacture. A replacement toughened glass panel is built with the dog-flap hole pre-cut, then heat-treated. On double-glazed units the spacer bar is routed around the opening to maintain the airtight seal.

3. Fit. On installation day we remove your old pane, fit the new one into the existing frame, and install the dog flap with a weatherproof seal. On-site time is 1–2 hours.

The finished result is a glass door that looks and functions exactly as before — just with a tidy, sealed dog flap in one panel.

From £320 for a standard dog-flap installation in a glass door, including the new toughened glass panel, the dog flap itself and full fitting.

The exact price depends on:

• Panel size — larger panes cost more to manufacture
• Glazing type — double or triple glazed
• Flap size — a small dog flap is cheaper than a large-breed door
• Flap brand — Pet-Tek is mid-range; premium microchip pet doors cost more

For comparison, a dog flap fitted into a UPvc door panel starts from around £120 because no replacement glass is needed. Use our cost calculator for a tailored estimate, or request a quote with a photo of your door.

Two key timescales:

• Manufacture of the new toughened panel: 5–10 working days from confirmed measurements.
• On-site fitting: 1–2 hours once the panel is ready.

Total turnaround is usually 1–2 weeks. If you have a deadline (moving house, new puppy arriving), mention it when you book — we can usually plan around it.

Puppies grow fast, so predicting the right flap size can be tricky. Two options:

1. Buy for the adult size — measure the parents or check the breed standard, then fit a flap the puppy will grow into. Most puppies adapt quickly to a slightly oversized flap.

2. Start with a medium flap and upgrade later — we can replace the glass panel again when the dog is fully grown. The frame and flap are the only changes; the door itself is untouched.

Either way, we always measure the dog at quote stage and advise on the best size for your breed and expected adult dimensions.

If you'd like a quote for your job for a dog flap in a glass door, send us a photo and your dog's breed/shoulder height. We cover the North West, Cheshire, Staffordshire, Yorkshire and North Wales — and we supply and fit all major brands including Pet-Tek, SureFlap and PetSafe.

See our glass door fitting service for more details, or jump straight to our Pet-Tek brand page to learn why it's the top choice for glass.