How to solve the problem of needing a dog door but, for whatever reason, you can’t install it in an existing door or wall to the outside? Sometimes quick and dirty is the best you can do. And what if you need to knock it down and move it?

I've never written an Instructable before because I figured most of my ideas are so simple and "make do with what you've got" that everyone has already thought of them. But I've had so many comments from neighbors and service people on this solution that I decided to go on and share it with you. I'm entering this in the Pets contest. Give me a vote if you think it's useful.

We're a retired couple with the usual aches and pains. Three years ago, we rented a house with a large, fully fenced-in back yard. When we lived in an apartment, we had to walk our two little dogs (Bingo, a long-coat chiweenie, and Doobie, a full-on wacko greyhuahua) two or three times a day, and sometimes it was just way too hot, cold, rainy, or snowy for old folks like us to bear. (Not to mention that we have a lot less energy than our dogs do.) "At last," we thought (hah), "now the dogs can go outside anytime they want to and we won’t have to deal with the weather!"

Do you realize how often and insistently a spoiled rotten little dog will beg you to go outside, come back in, go back out, come back in, go back out, come back in, ad infinitum? Multiply that by two. It soon became clear that we'd drop dead or go mad without a dog door.

Step 1: The Rub and the Concept

We couldn’t cut into the existing door or walls because we don’t own the house and, besides, that would cost an arm and a leg. (Been there, done that. We’ve been carting around a 36-inch 9-lite metal exterior door replete with an expensive Plexidor dog door from when we owned a house and two other little dogs 20 years ago. We were hoping we’d eventually be able to use that door again but, bummer, it doesn’t fit this house.)

Our landlord warned us that when she was living in the house and had a dog door installed, raccoons (and even neighborhood kids when she wasn't home) kept coming into the house through that dog door. (She had it filled it in with concrete, so we couldn't have cut through that wall even if we'd wanted to.)

You know what they say: Necessity is the mother of invention. We needed something cheap, serviceable, removable, and installable by me that would quickly get the job done. Ideally, it would not be a welcome sign for all the wild things. We're on low fixed income, so we pretty much had to make do with what we had and what we could scrounge. I figured it didn't have to be pretty, although it could have been. Function first is my motto; later, I'll put in a screen or another trellis with flowers to make it less of an eyesore.

Step 2: Items Needed

A pet door that will free-install in a window, like you buy for cats. We got ours from Amazon (ASIN B004Q01RIE).
A window. You probably already have one. We chose the one in my bedroom that looks out onto the noisy old heat pump on the "ugly" corner of the back of the house. Mindful of raccoons, I hoped the heat pump cycling on and off might help deter any opportunistic critters.
Something sturdy and weather resistant to make outside steps leading up to the window. We used a hodgepodge of old concrete blocks, caps, and 16" pavers. Optional, but advisable, if you have leash laws: a fenced area. (Conceivably, if you have a larger dog that can still get through a pet door sized to fit a window, you won't even need any steps, outside and/or in, in which case all you need is the pet door and the window.)
A ramp or steps of some kind for the inside. We used an easy-clean brown faux leather storage bench we already had (Amazon, ASIN B00PC74FQG) because dogs’ feet get dirty. We also put a small non-slip rug on top of it to help catch dirt. The step is a bit high for Bingo, who is getting arthritic, but we'll add another step or change the bench out for a ramp when it gets too hard for him to jump up on it. (TIP: You can use your bed or a chair with a blanket thrown over it for the inside access; just know that you’ll be doing a LOT of laundry.)

Step 3: Building It

Raise the window sash and install the pet door per the manufacturer's instructions. It shouldn't be a big deal. Worry about weatherstripping it later, if needed. If it has a hard door covering like ours does, close it until you're done with all the building steps.
Set up the inside step/ramp with whatever you can come up with. Just be sure your dog can climb up and down easily. You can now put something they will be interested in on top of it. Let them discover it on their own. (If you've chosen a pet door like ours, it will have little windows on either side of the still-closed door. I like the storage bench because our dogs quickly discovered they could jump up on it and watch me through the window as I worked on the next step. This helped get them interested in the dog door setup and made getting them used to it much easier later on.)
Build the outside steps, eyeballing the step depth and height according to your dog's size and needs. You can level the steps, or you can take your chances. I made a stab at it, but I'm pushing 70 and I didn't have what it took to get mine totally level. The main thing is, whatever materials you decide to use, come up with something stable enough that it won't wobble scarily or fall over. If you mess up, it's not like you can't rebuild it later.

Step 4: Using It

All you have to do now is encourage your dog(s) to use the door, and how you do that will vary depending on their personality. The instructions that come with your particular pet door will have good advice, or check YouTube. The main thing is, you don’t want to force it. They need to think this is their freedom and secret pleasure, not your convenient way of getting them out of your hair. If you lose patience and try to force them through the door (I finally did that with Doobie), it may set you back. But if one dog gets the hang of it, the other is sure to follow eventually.

This is how we got our dogs to take to the setup, and it happened rather quickly. We first let them outside through the patio door and let them run around doing their business as usual. While they were doing that, but before I knew they’d be asking to come back in, I put a few training treats on each of the outdoor steps up to the windowsill and a few super-good-smelling pieces of chicken on the inside of the door flap and on the inside step. Then, when they were about ready to come inside, I just casually said "Oh, look what I found." When they took the bait, I went inside.

When one of the dogs started nosing against the flap of the dog door to get at the chicken, I’d raise the flap from the inside and say “Are you ready to come inside? You can come inside.” I ignored them when they barked to be let in through the patio door, so they eventually came to the dog door and barked to get me to let them in there. I'd then do the same thing: raise the flap and say "You can come inside. Come on."

It didn’t happen right away, and Bingo was more precocious than Doobie was (and got all the treats at first), so if you have more than one dog you might want to work with them separately. But soon, both dogs were tearing through that door, racing up and down, in and out of the window to bark at cars, chase squirrels, etc. That's where the doggie gym part comes in. On occasion, I'll close the door during the day when I want them to stay inside and forget I've done it, and they'll follow me out into the garden through the patio door. Then they'll come and bark at their dog door to let me know I need to open it up again.

Step 5: Final Comments

We have had no raccoons or other unwanted critters come into the house after two years, although Doobie once brought in a dead squirrel he'd managed to catch and proudly placed it at my feet. Yuck. I did have to start closing the dog door after 9 p.m. to keep them from going out at all hours of the night barking at every little sound they heard. There are coyotes around here, too, so I do this to protect them, just like I lock up my chickens at night.

The morning routine is to open the dog door and tell them they can go outside. Then Robert and I have our coffee and slowly wake up in peace. Bingo and Doobie come inside after they've done their business, and we all do the "contented pack time" thing for a while. But little dogs live to bark. Whenever they start up their ear-splitting barking at neighbors out walking or trucks passing by, we just frown and say, "Go outside to bark." And they do...no human intervention required. The dogs are getting a lot more exercise than they used to, and we're feeling far less stressed.

One unexpected plus of the outside steps is that they heat up some in the sun during the day, and I've noticed Bingo really loves to lie out there on the steps. For one, he has little short dachshund legs and his favorite thing is to be up high on something. But I think the heat helps his arthritis, too (I know heat really helps mine), and it's free solar energy. You can't beat that! (Yes, for you astute readers out there, that's a sun oven on that table in my garden.)