Planning pet-door access for a dog or cat

Start with the question, not the door

A pet door lets a dog or cat go in and out without waiting for someone to open the back door. It also changes who decides when your pet is outside, so it is worth planning before anyone measures a wall or orders anything.

Most of the detailed guidance used here comes from outside the United States. The Ontario SPCA and Humane Society, in Canada, publishes dos and don’ts of using a pet door. Cats Protection, a U.K. charity, writes about cat flaps from a country where many owners let cats outdoors. Those norms do not automatically fit an American home.

For cats in particular, the U.S. organization Humane World for Animals asks pet owners to keep their cats indoors, and says cats can experience nature safely in a catio, screened porch or other secure outdoor enclosure. If you have an indoor cat, a pet door into an enclosed catio may be the version that fits. Our indoor cat enrichment guide covers the rest of the cat’s day.

Look at the space on the other side

The Ontario SPCA says pet doors should lead into a secure enclosed confinement space to keep pets safe. Before you choose a door or wall, stand outside it and ask where your pet could go from there.

• Fences and gates. The Ontario SPCA notes that cats can climb fences and head off on their own, so it recommends supervision. We would also check that gates close and latch on their own, and that nothing near the fence works as a step.
• People who visit the yard. It advises keeping the pet door locked while a gardener or pool cleaner is working, and when you are using any dangerous gardening equipment.
• Food and water. It suggests keeping food and water away from the pet door, so other animals are not tempted to use it.
• Time alone. It says pet doors should stay locked when you are not home to supervise outdoor time.

If the honest answer is that the yard is not secure yet, fix the yard first, or keep using the ordinary door with a person beside it.

Choose the door or wall with the route in mind

The rest of this section is Housemates planning suggestions, not instructions from a source. Think about the route your pet will take, not only the opening. A door into a side passage your pet rarely uses may never feel natural. A door from a busy kitchen straight onto the yard may suit a dog but crowd a cautious cat. If you rent, ask your landlord before changing any door or wall, and leave the fitting itself to the manufacturer’s instructions or a qualified installer.

The Ontario SPCA adds a practical point: if the ground outside is too low, or you have a short-legged or senior dog, you may need a ramp. It also describes electronic doors activated by a control on the pet’s collar, or sometimes the pet’s microchip, which can help in homes with more than one pet. Cats Protection’s cat flap guidance says microchip or magnetic flaps can stop neighbouring cats entering your home.

Housemates is published by Hale Pet Door, which has made pet doors in the USA since 1985. This guide does not recommend any brand or model, and nothing here has been tested by Housemates.

Measure your pet, then check the maker’s chart

The Ontario SPCA suggests measuring your pet’s width at the widest point and its height from the floor to the top of the shoulders, then adding an inch or two for safety. It says your pet door retailer should have a sizing chart to help you find the best fit.

As an original Housemates suggestion, measure every pet who will use the door, on the same day, and write the numbers down with the date. A growing puppy or kitten will change, so plan to measure again. Treat your numbers as a starting point and confirm the size and fitting height against the manufacturer’s own instructions before anything is cut.

Walk the route and write a measuring record

This is an original Housemates exercise. Do it on paper, before you buy anything.

1. Stand at the door or wall you are considering. Note which room it is in and what sits nearby: food bowls, a litter tray, a bed, a busy walkway.
2. Walk outside the way your pet would. Note the step down, the surface underfoot and anything your pet would have to squeeze past.
3. Follow the route to the yard boundary. Walk the whole fence line. Mark each gate, gap, low section and anything a cat could climb.
4. Mark who else uses the yard. Gardeners, pool cleaners, delivery routes, children’s friends. These are the times the door will be locked.
5. Write the measuring record. For each pet, record the name, the date, width at the widest point and height from the floor to the top of the shoulders.
6. List the open questions. Anything you could not answer, such as whether a gate latches reliably, goes on the list to fix before the door is used.

Teach the flap slowly

The Ontario SPCA notes that pets often need some training before using a pet door. It suggests waiting until your pet is interested in going outside, using treats if necessary, and being patient. It also says never to push or force a pet through.

Cats Protection describes a simple sequence for cats:

1. Hold the cat flap open and lure the cat near it with treats.
2. Give treats little and often to reward progress.
3. Hold a treat on the other side of the flap and call the cat’s name to encourage it through.
4. Repeat until the cat goes through happily in both directions.

If a cat is new to the home, our first-room guide comes before any of this.

Decide when the door locks

A lock schedule is part of the plan, not an afterthought. The Ontario SPCA says to lock the door when you are not home to supervise. It also reminds dog owners that a pet door does not replace regular exercise and play time.

For cats, Cats Protection recommends keeping cats in at night to keep them safe, noting that some studies suggest more road traffic injuries happen late at night. It suggests a clean litter tray and fresh water, kept far apart, for the night. It also describes flaps with a timed curfew, after which the cat can no longer leave through the flap.

Add the lock schedule to your household emergency plan so a helper knows how the door is normally set.

This guide is a household planning aid. It is not installation, security or veterinary advice.