Installing a Dog Door in a Sliding Glass Door

Border Collie coming through the dog door inserted in a Sliding Glass Dog door

Installing a dog door for your pet does not mean you have to spend hundreds of dollars for a small section. It also doesn’t mean you have to completely replace your existing glass door along with its frame and fittings. Dog doors can be easily fitted into your existing sliding glass doors by only making a few modifications.

Commonly known as the patio panel pet door, dog doors in sliding glass doors offer a simple yet great solution. The dog door you wish to install can be of any size so it can accommodate your pet. You will no longer have to make a hole through your wall or break a door down to incorporate a dog door for your pet.

The way dog doors work in sliding doors is that a panel is inserted in the track and the door is divided into two portions. The new panels that are inserted have glass on top and a pet door at the bottom. The pet door is usually a flap that can be easily moved by the pet without any assistance. The slider of the door slides in its track against the panel. The track for the door becomes shorter because of the additional panel inserted.

Following are the easy steps that you can follow to install a dog door in a sliding glass door in your home:

1. Check the design of your door

The first step is to check your sliding door and measure the track of your door. You have to see if the track your door is sliding in is a monorail one or not. It is a bit easier when the track is not a monorail, as the panel can easily be adjusted. However, if the track of your door is a monorail, you will have to check if it can accommodate a panel insert. The panel that is inserted forms a partition and divides the whole door into two parts. One part is the solid one with the door and the other is the sliding door.

2. Measure your pet

This is a significant step as the success of your dog door very much depends on it. You don’t want to end up with a dog door that is too small or too big for your pet.

To measure your pet, you should take measurements of the widest part of your pet’s body and add 2 inches to it. For the length, measure how tall your pet is from its shoulder to its feet and add 2 inches to it. These measurements will make a large enough flap that the pet will find comfortable for use. It will also ensure that no larger animals from the outside can enter into your home through the flap.

3. Position the flap on the door

Next, you should cut a piece of cardboard that will give you a good idea where you are going to place the flap in your sliding door. You should place the flap in a corner area that will not disrupt the functioning of the sliding door. The spot where you place the flap should also be a convenient spot for your pet to find.

4. Measure the sliding door

The next step is to find the length of the door that will match your slider. After you install an additional panel for the dog door, the area of your door is going to decrease. Take the measurements of the door and find measurements for the panel you will install. The size of the panel will also incorporate the width of the flap you are going to install in it.

After you are done with taking all the measurements, you can order a panel with your specifications and the panel of your choice. At Pet Doors, there are is an extensive collection of panels that you can use for your sliding door. Choose the one that fits your style and is okay for your pet.

5. Dry fit the panel

Soon after you have ordered the panel, you will receive the same one from Before installing the panel, dry-fit it to see if any corrections are needed. Dry fitting the panel will help you get a good picture of how your door will look like after the modification.

6. Fit the panel in

If everything is as planned and the panel you got is perfect, it is time to fit the panel in your sliding door. Place the panel in the bottom track and place it in the spot you want it to. Twist the screws from the bottom part so it is stable and you can position it from the top.

The panel for the sliding door comes with some type of pressure system towards the top end, from where it expands and fits in the height of the track. Mostly, the panels do not require any extra tools to fit. Once you have positioned it perfectly, tighten the screws and fix it in the spot so it doesn’t move.

7. Finalize the installation

Once you have fit in the panel, you are almost done with all the work. Install any insulation or any other material that may come with the panel. Follow the steps carefully and you will have a new patio panel in your sliding glass door.

The addition of a dog door in the sliding glass door is an excellent option if you have a pet. Instead of breaking your walls for the dog door, a patio panel brings aesthetics to your sliding door and fulfills the purpose you wanted. There are many kinds of panels that may be installed in your sliding door, but they all typically follow the same procedure with a few changes.

The selection available at Pet Doors is of high-quality and a preferred option for many customers. Visit and choose the one you like.

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4 thoughts on “Installing a Dog Door in a Sliding Glass Door

  1. Lajuan

    But what do you do about the air coming through the sliding doors where they no linger meet at the frame edges? I cannot get them sealed no matter what i do.

    1. Kate Miller

      I have just the solution for you! For anyone having issues with air passing through their slider, we highly recommend using what we call the “Draft Stopper,” found here: It’s designed to seal the gap created between stationary and sliding glass doors when a panel doggy door is installed.

      The center post weather seal strip (draft stopper) should be installed on the inside of your home. It can install on either the back edge of the sliding door panel or the leading edge of the stationary panel. Then, you can trim it with scissors as needed to fit the desired width and length. Make sure you clean the edge of your patio door with rubbing alcohol before installing to assure a good seal.

      I hope this helps! If you have any more questions, feel free to send us an email at We’re happy to help!

      1. J.B.M.


        I purchased one of your pet doors for our vinyl sliding glass doors, and the installation went relatively smooth. I had to order an extra extension, as my door was a bit taller than the standard sizes. I like the look of it and am close to being very happy. There is one nagging issue. I sprung for the double pane, as insulation is important. However, I didn’t consider that there would be such a significant gap left between the existing sliding glass doors, as now the doors are not fully matched up frame to frame when closed. The tape that was provided (the draft stopper you mentioned above) to close this gap does not form a seal, does not remain stuck (it’s simple tape glue?) when the wind blows, and is in general a lot less insulation than existed before. So we now have a significant air leak coming through the gap left between the two prior existing sliding glass doors when they are in the closed position. Do you have a better solution for this? At this point, I’m regretting not just having a door installed in the wall…

        1. Kate Miller

          Hi there!

          We’re all about solutions! To better be able to make a recommendation, we’ll need some more specifics. Be on the lookout for an email from PetDoors! Depending on the details, we can find a way to get your door back to its full insulating potential. I look forward to hearing from you!