How to Build a Pet Door

While not everyone views a pet door as a good option, it can be a convenient way for pets to have access to the outside. With a pet door, pets can exit and enter the house when their owners are busy or unavailable. These little doors work especially well for small dogs whose owners have a fenced yard or an invisible electric fence. The dog can stroll out when nature calls at night or when the owner is away.

Start the project by deciding where the door will be.

Most pet doors are a part of a larger door. However, they can be built into a wall almost as easily as into a door. Generally, the pet door will be located at a place that will give the pet an exit to an area that is safe for it to be.

Measure the height of the pet to make sure that the opening will be the correct size.

Remove the door that will contain the pet door from the house. Be careful to mark the bottom of the door in some way. Lay the door across two saw horses to measure and cut the opening. Centering the pet door into the larger door is the most attractive placement. To accomplish this, measure the full width of the door. Divide this length in half. Measure this new distance from one edge and mark it. Check your accuracy by measuring the distance to the other side of the door. If these distance match, you have marked the center.

Divide the width of the pet door by two.

Measure this distance to the right of the center and mark it. Now, measure the same distance to the left and mark it. Measure the length of the distance between these last two marks. If it is the desired width of the pet door, you have centered the door correctly.

From the center mark, measure up the door the length of the height of the pet door and mark it.

Measure this same length up the door from the marks at each edge of the pet door. Using a straight edge, draw a light line connecting these 3 new marks. Extend the line slightly beyond the limits of the marks. Measure the distance from the right edge of the door to the right edge of the pet door. Now, measure this distance from the right edge of the door along the line that you drew. Mark this spot clearly. Do the same process from the left side of the door. You should now have marks at each of the four corners of the pet door. Connect these marks with straight lines to lay out the saw lines cutting out the pet door.

Using a saw, cut out the outline of the pet door.

Be careful not to cut beyond the boundaries that you have sketched. If you have a hollow core door, you will need to measure the interior width of the door. Cut pieces of wood to the dimensions of the pet door the width of the door's interior space. Make the top piece about 2 inches longer than the opening is wide. Using carpenters glue and clamps, position the board with about an inch extra on each end. Apply the glue to each side and clamp the board into place. The other two boards should be cut just to fit. Glue and clamp them into place. If you must complete this project in a day, you nail these pieces into place instead of clamping. if you are dealing with a solid core door, this process is not necessary.

Use double action hinges so the door will swing both ways.

Measure the thickness of the hinges. Cut this amount from the length of the pet door. For a hollow core door, follow the same process for adding support wood to the inside edges of the pet door as the main door. Stain or paint the new edges of the main door and the pet door to match the finish on the exterior of the doors.

Attach the hinges to the top of the opening in the main door.

Now, attach the hinges to the new pet door. Push it back and forth a few times to make sure it swings freely. You may need to remove the pet door and shorten it about 1/4 inch if it does not swing freely. Remove this from the bottom of the door. By doing this, you can paint or stain this bottom area at your convenience after the door is attached. Retest the door. It should now be ready to test with a training run for the pet.