Pet Door Installation on San Juan Island

This is a small job that gets done badly a lot, and the reason is that people think of it as fitting a product when it is really cutting a permanent opening through a wall or a door. I install pet doors three ways: into an exterior door, through an exterior wall, and into a screen door or window screen. The product is the easy part. Whether water, wildlife, and winter air get to use the opening is down to the details.

The island specifics are worth taking seriously. Raccoons are the big one. They are dexterous, curious, they learn by watching your dog, and a pet door is one of the easiest ways for a raccoon to get inside a house — wildlife agencies list an open pet door among the standard entry routes, and it is far from a theoretical problem out here. Rats and mice are the quieter version: a flap that no longer seals to its frame, or a wall tunnel that was foamed instead of properly boxed and sealed, is a highway into the same wall cavities I spend my winters sealing on the crawlspace and rodent exclusion page. And deer, who will not use a pet door but will absolutely walk up to a door at grade and clean out the pots beside it, are a reminder that the flap should not be your garden strategy — that is deer fencing.

The other island fact is that most of these houses sit empty for long stretches. A pet door that cannot be closed properly is a real liability in a house nobody visits between October and May, so I fit units with a solid locking cover as standard and I show whoever is checking the house how to secure it. One honest caveat that comes straight out of the manufacturers’ own literature: a closing panel is there for weather and appearance, and it is not a security device. If security matters, the door itself gets the lock, and the pet door gets a cover and a house that is being looked at.

Door or wall is the first real decision. Cutting into an existing door is quicker, cheaper, and reversible in the sense that a new door slab can be bought later, and it is the right answer when the door is a flat-panel or flush wood or fiberglass slab with enough clear area. Going through a wall costs more, takes longer, and is the better answer more often than people expect: it lets me put the opening where the dog actually walks, at the right height, in a sheltered elevation under an eave rather than on the weather side, and it works when the door is all glass or when its construction rules it out. A wall pass-through also leaves your door intact, which on an old island house with a door nobody can replace is worth a lot.

Here is the honest list of what a door can and cannot take. A hollow-core door is a no from me; there is nothing inside it but cardboard lattice, it is not an exterior door anyway, and a flap cut into one tears out. An insulated steel or fiberglass slab with a foam core can usually take a pet door with the right kit, but the cut edges have to be sealed so water never reaches the foam or the steel skin from inside the cut, and the frame has to clamp properly through the skin — and it will void the door manufacturer’s warranty, which you should hear from me before I cut, not after. A door with insulated glass in it cannot take a pet door at all: you cannot cut a sealed glass unit, and no, not even the bottom panel. On a panel door I need a flat panel area with sound stile and rail left intact on all sides, because cutting into a stile or through a lock rail weakens the whole slab. And the door between an attached garage and the house is a fire-rated assembly — cutting a hole in it destroys what it was there for, and I will not do it.

The wall pass-through is the job where craft actually shows, because you are breaching the water-resistive barrier on purpose. My sequence: locate the framing, confirm there is nothing in that bay before anything is cut — if I cannot verify what runs in the wall, I move the opening or open a small inspection hole rather than guess — then frame the opening properly with a header and jack studs sized to the span, insulate around the tunnel, and treat the exterior side exactly like a window opening. That means a sloped sill so water runs out, self-adhered flashing tape lapped into the existing barrier so anything getting behind the siding sheds outward, sealant at the sides and head of the flange, and the bottom left open to drain. A pet door tunnel sealed all the way around, including the bottom, becomes a bathtub inside your wall, and that is exactly how a five-hundred-dollar installation turns into the rot repair I cut out three winters later.

Winter performance is a genuine question here rather than an upsell. Eight wet months, regular southerlies, and a flap facing the wrong way will chill a room and slap all night. So: dual-flap units with an air space between them on any exposed wall, magnetic closures with weighted flap bottoms, a frame with real gasketing rather than a friction fit, and placement out of the prevailing wind under an eave wherever the layout allows. Flaps are consumables. Cold makes vinyl stiffer and less willing to reseal, salt air and grit stiffen the hinge line, and dogs are hard on them, so figure on replacing flaps and magnets every few years and keep a spare on the shelf. Stiff flaps also matter for small and elderly animals, who will simply stop using a door they have to shove.

On electronic options, one clear rule: anything I fit is battery-powered only, the sort that reads a key on the pet’s collar and locks the flap otherwise. Those solve the raccoon problem better than anything mechanical, and they are the right choice on a rural property with an animal that goes out at night. I do no wiring of any kind — no hardwired unit, no transformer, no running power to a door. That is licensed electrical work in Washington. Worth knowing before you buy: batteries in an unheated wall run down faster in the cold, so a battery-powered unit on an empty house needs somebody checking it, which is a natural line item on a property care visit.

The last details are sizing and getting out. I measure the animal at the shoulder and add a few inches, size the opening to the widest part of the animal rather than to the label on the box, and set the flap bottom at a height the animal can step over rather than climb. Older and shorter-legged dogs often need a step or a small platform on both sides, and a wall installation needs a landing outside that is not a mud pit by December. I finish the interior trim so it looks like it belongs on the house rather than like a product bolted through a wall, and I take the offcut with me. Where an existing pet door is the problem — broken flap, leaking frame, wrong size, or one that needs closing up permanently — framing the opening back in, insulating it, and patching siding and drywall so it disappears is the same trip.