
G-SDDB – Catwalk® Glass-Fitting Maxi Pet Door
Dual Glaze
The cat door for double glazing — and the small-dog door too. The Maxi clamps through glass from 3 to 28 mm with a 267 mm round cut-out, and its 187 × 190 mm opening takes every cat, big breeds included, and small dogs to about 300 mm at the shoulder.
Colour Black G-SDDB
Retail checkout opens soon · glaziers, installers and retailers: trade pricing via the trade button.
Often bought with this door
Replacement flapG-SDDRF · $26Enquire
4-way locking dial setG-LDSDDC · $13Enquire
Replacement flapG-SDDRF · $26Enquire
4-way locking dial setG-LDSDDW · $13Enquire
Replacement flapG-SDDRF · $26Enquire
4-way locking dial setG-LDSDDC · $13Enquire
Specifications
G-SDDB- Fit
- Glass cut-out
- 267 mm round
- Frame projection, inside
- 16.22 mm
- Frame projection, outside
- 11.72 mm
- Size
- Usable opening W × H
- 187 × 190 mm
- Flap panel W × H
- 187 × 203 mm
- Overall frame
- 306 mm round
- Build
- Flap
- UV-stabilised polycarbonate
- Locking
- 4-way dial open · in · out · locked
- Barcode GTIN-13
- 9421006252490
A cat door that fits double glazing
“Can you put a cat door in double glazing?” is the question we hear most, and the Maxi is the answer. Its frame spans glass from 3 to 28 mm, which takes in a sealed double-glazed unit as well as a single pane. The glazier orders the new unit with a 267 mm hole already in it, clamps the door through, and the seal is complete on both faces.
Big enough for any cat — and small dogs
The opening is 187 mm wide by 190 mm high. That takes the biggest cats without squeezing, and small dogs up to about 300 mm at the shoulder. The flap is UV-stabilised polycarbonate on a magnetic catch with a brush seal all round.
Four-way lock
Entry only, exit only, both ways, or locked — turn the dial. Curfew the cat at night, keep her in before a vet visit, or shut the door completely when you are away.
Download the installation guide (PDF) — the sheet your glazier will want to see.
Single glazing or a slider? Choose the Slim Line
The Maxi Slim Line has the same opening in a 9 mm frame for single glazing 3–21 mm. If you only want a standard cat opening, see the Catwalk Standard.
What arrives
- Catwalk Maxi Dual Glaze door — inner and outer frame
- Polycarbonate flap with magnetic catch, fitted
- 4-way locking dial, factory fitted
- Four fixing screws, cut to length on site
- Installation guide
To be installed by a professional glazier.
Care
Wipe the flap and frame with a damp cloth and mild detergent. No solvents, no abrasive pads — they haze polycarbonate. The brush seal can be replaced if it wears; ask us for the part.
Warranty
3 years on the door against manufacturing and parts defects; 1 year on movable parts — the replacement flap (G-SDDRF, $26) and the 4-way locking dial (G-LDSDDC, $13). Excludes accidental damage, misuse and normal wear. Keep your proof of purchase. This sits alongside, and does not limit, your rights under the Consumer Guarantees Act 1993.
What your glazier will do
- 1Measure belly height. Floor to your cat’s stomach while standing — that is where the bottom of the opening goes. Cats: 100–150 mm.

- 2Mark and scribe. Mark that height on the glass from the outside and scribe a 267 mm circle — this is the cut-out.

- 3Cut, or replace. Single glazing: the glazier cuts the hole. Double glazing or toughened: the glazier supplies a new pane with the hole already made.
- 4Fit the two frames. Outer frame in from outside, inner frame over it from inside — a slip joint that closes against the glass.

- 5Screws. Cut the fixing screws to length and tighten firmly. Do not over-tighten.

- 6Test the lock. The dial comes fitted — turn it through all four positions to check.

Four-way locking

Entry only · exit only · both ways · locked.
Watch the installation
Download the printable guide for your glazier.
Two measurements
Measure your cat’s width at the shoulders and the depth from the top of the shoulders to the bottom of the chest; add 25 mm to each and both should fit inside the opening. Fit the door with the bottom of the opening 100–150 mm off the floor.
Multi-pet home? Size for the biggest, fit for the smallest — the bottom of the opening at the smaller animal’s belly height.
Which glass door
| Your cat | Door |
|---|---|
| Cats to about 7 kg | Catwalk Standard |
| Big cats & small dogs, to ~300 mm | Maxi — this door |
| Keep other cats out | Multi-Magnetic |
What owners say
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Before you buy
Can you put a cat door in double glazing?
Yes, with this door — but not into the pane you already have. Sealed and toughened units cannot be drilled after manufacture, so the glazier orders a replacement unit with the 267 mm hole pre-cut and fits the Maxi through it. The door takes glass up to 28 mm.
How much does it cost to put a cat door in a glass door?
The door is the smaller part. Add the glazier’s time and, for double glazing, a new sealed unit sized to your frame — glaziers quote that per panel. Single glazing is cheaper because the existing pane can usually be cut.
Will a big cat fit?
Yes. The usable opening is 187 × 190 mm, which suits every domestic cat including the large breeds, and small dogs up to about 300 mm at the shoulder.
Maxi or Standard — which cat door do I need?
The Standard (G-CD) has a 165 × 180 mm opening for single glazing 3–10 mm. Choose the Maxi for a big cat, a small dog, or any double glazing.
Does it lock?
Four ways: in only, out only, both, or fully locked. The dial comes fitted — turn it through the positions when the door is in to check.














