If you have ever priced pet doors at a store, then you may be interested in building a cat pet door and saving some money. This project is for wood doors. Fiberglass and metal doors can also have pet doors installed, but require different saw blades to cut the house door.
Exterior house doors are usually solid or laminated wood. In that case, you will not have to make a frame around the hole, as described in Step 3 below. However, instructions are also provided here for installing a pet door on an interior hollow wood door.
Step 1 - Remove the House Door
Remove hinge pins by pushing them up and out using a screwdriver and hammer. A second person makes removing the door and lying it in your work area easier and safer, especially if it is a heavy exterior door.
Step 2 - Determine Size and Location and Cut Hole
Be sure you make a pet door big enough for your full-grown pet. Once you know the size, draw the dimension of the hole on the house door using the level or ruler for straight lines. Leave 2 to 3 inches at the bottom to retain door integrity. Use a jigsaw to cut the hole. On a hollow door, mark the outline on the opposite side in the same location and cut. Be sure the cuts match. If you bought a rubber door flap, use that as a guide for the dimensions of your cut.
Step 3 - Finish the Cut with Trim
If the door is hollow, make a frame for strength and pet safety. Do this by measuring the distance between the two door panels. Cut plywood strips and glue them around the hole, making a frame and sealing off open space inside the door. Cut decorative wood trim to fit around the hole on both sides of the door, and attach with screws. Paint or stain the trim and frame.
Step 4 - Install the Flap
If you purchased a flap, follow the manufacturer's directions. If you are making one, then attach the two hinges to the top inside of the frame you made, or to the top inside of the hole on a solid door. Using a razor knife, cut the rubber so that it fits inside the frame without rubbing against it. Make the fit close to prevent drafts. Now hold the rubber mat against the hanging hinge and attach it with screws. The door should flap easily in both directions.
Step 5 - Finish and Train Pet
Reinstall the house door. If necessary, use the hammer to insert the door pins. Now you can teach your pet to go though the door.