How to Build a Homemade Pet Door

Measure your pet. Pets can squeeze through spaces narrower than they are, but don't make the opening too tight. Make it approximately the pet's current size to allow for added winter pounds.

Remove door from hinge. Lay out on sawhorses.

Measure out the size of the opening close to the bottom of the door and outline with pencil, using the ruler to correct straight lines. Leave 1 1/2 inches at the bottom.

Drill holes at the corners to allow the blade of the jigsaw to start cutting.

Insert jigsaw and cut the rectangular opening for the animal.

Screw 1 1/2-inch molding on the sides and bottom of the outside portion of the opening.

Staple polyethylene plastic strips of equal length to the top of the opening on the outside of the door, to allow you pet to pass through.

Screw molding over the stapled area to create a good appearance on the outside of the door.

Screw the 1-inch flat strips of wood securely on both sides and bottom of the opening on the inside of the door 1/2 inch from the edge of the opening. Cut strips 3 inches longer at the top to hold the door when it is in an open position.

Screw the 1 1/2-inch molding on top of the strips, allowing 1/2 inch to overhang the opening.

Cut the plywood to fit inside the "track" of the overhanging molding.

Stain molding and plywood with a color that matches the door.

Varnish molding and door to seal wood.

Attach brass eye from hook-and-eye hardware to the inside surface at the top of the sliding door to hold it in an open position to allow the pet to enter and exit.

Attach hook to the inside door to allow it to hold brass eye on the door to hold door open.