Guide · · 4 min read
Dog door for double glazing: what your glazier needs to know
A dog door can go into double glazing — but not by cutting the pane you have. Here is how the job actually works, what to tell the glazier, and which Dogwalk® doors fit.
By the Pet-Tek International team, Auckland — designers of Catwalk® and Dogwalk® since 1999.
Most New Zealand homes built or renovated in the last twenty years open onto the deck through double glazing. That is good news for the power bill and, at first glance, bad news for the dog: you cannot cut a hole in a sealed unit. The good news is that nobody has to. A dog door goes into double glazing every week in this country — the pane just arrives with the hole already in it.
Why the existing pane cannot be cut
A double-glazed unit is two sheets of glass sealed around the edge with a dry gas gap between them. Cut one sheet and the seal is broken, the gap fogs and the unit is finished. Most modern units are also toughened, and toughened glass shatters into pebbles the moment a drill touches it. So the glazier does not cut your pane; they measure it, order an identical unit from the glass factory with a round hole cut in both sheets before toughening, and swap the new unit into your existing frame. The frame, the slider and the lock are untouched.
What to tell the glazier
Three numbers, all on the product page: the cut-out diameter, the glass thickness range the door clamps through, and where on the pane the hole goes. For the Dogwalk® Medium Dual Glaze that is a 385 mm hole in glass anywhere from 3 to 32 mm thick, with the bottom of the opening at your dog’s belly height. Print the installation sheet from the product page and hand it over; it has the drawing.
Ask the glazier to keep the hole at least 100 mm from any edge of the pane and clear of the handle side of a slider, so the open door does not foul the pet door.
Which Dogwalk® door fits double glazing
The Dual Glaze models. Their two frame halves clamp through glass up to 32 mm, which covers every standard residential unit. The Slim Line models are a shallower frame for single panes and sliders up to 13–21 mm and will not reach through a sealed unit.
- Dogwalk® Medium Dual Glaze (G-DD) — 270 × 300 mm opening, dogs to about 500 mm at the shoulder. Clear, white or black. 385 mm cut-out.
- Dogwalk® Intermediate Dual Glaze (G-IDD) — 216 × 237 mm opening, dogs to about 380 mm. 320 mm cut-out.
- Catwalk® Maxi Dual Glaze (G-SDD) — 187 × 190 mm, large cats and small dogs to about 300 mm. 267 mm cut-out.
Not sure which? Measure your dog from the floor to the top of the shoulder blade — Find your door does the rest.
How the installation day goes
- Measure. The glazier measures the existing unit and notes where the hole goes. You can have the door on hand so they can check the frame against the drawing.
- Order. The new unit is made with the hole; allow a week or two.
- Swap. The old unit comes out, the new one goes in. Same frame, same beads.
- Fit the door. Outer frame in from outside, inner frame over it from inside, screws cut to length and tightened. Fifteen minutes.
- Test the lock. The 4-way dial comes fitted; turn it through all four positions.
The video on the product page shows the fitting end to end.
What it costs
The door costs the same whether it goes into single or double glazing. The extra is the new sealed unit and the glazier’s time, and that depends on the size of the pane and where you live. Get two quotes, give both the cut-out size, and ask whether the price includes disposal of the old unit.
Three mistakes to avoid
Buying a Slim Line for a sealed unit. It will not clamp through 24 mm of glass. Putting the hole too low. The bottom of the opening should sit at the dog’s belly, so the dog steps through instead of crawling. Sizing by breed. A small labrador and a big one differ by 80 mm at the shoulder; measure the dog you have.
Questions we have not covered are probably on the FAQ page; otherwise email info@petnest.co.nz with a photo of the door and we will tell you what fits.
Quick answers
Can you put a dog door in double glazing?
Yes. The existing sealed unit is not cut; the glazier orders a new double-glazed unit with a round hole made at the factory, fits it, and the Dual Glaze dog door clamps through the hole. Dual Glaze frames fit glass from 3 to 32 mm.
How much does a dog door in double glazing cost?
The door is the same price as for single glazing; the extra cost is the new sealed unit and the glazier's two visits. Glaziers quote by pane size and region, so get two quotes and give both the cut-out diameter.
What size hole does the glazier cut?
385 mm round for the Dogwalk Medium (G-DD), 320 mm for the Intermediate (G-IDD) and 267 mm for the Catwalk Maxi (G-SDD). The number is on each product page and on the printable sheet.
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