How to Build Patio Doors for a Cat

Measure and mark a 8-by-14 inch rectangle on one side of the patio door, about 3 inches up from the bottom. Make the 14 inches the height and the 8 inches the width. Drill a hole into one of the corners of the rectangle using a drill and wood drill bit.

Insert the drywall saw or other small saw within the hole and begin cutting out the frame. Use the handheld saw when the opening gets large enough and use it to cut out the entire rectangular frame. Sand the rough edges of the frame with medium-grit sandpaper.

Position a 1-by-8 inch dowel in the center of the top and bottom surface of the frame to serve as the top and bottom attachment points for the flap, keeping the flap in the center of the hole. Set a long surface of the dowels flush with the top and bottom surfaces of the frame so that it is parallel with the threshold of the door.

Drill through the dowel, making three holes that extend into the top and bottom surface of the frame. Attach the dowel in place with galvanized 2-inch wood screws tightened through each hole.

Position an 8-by-13 3/4-inch rubber flap against the outside of the top dowel piece. Arrange it evenly across the two dowels and staple it in place, spacing the staples every inch.

Attach magnet strips of one polarity against both sides of the bottom of the rubber flap using glue. Attach magnet strips of the opposite polarity against both sides of the bottom dowel board using glue, so that when the flap is pushed through the opening it will seal on both sides of the dowel.