A dog door without a flap is effective in letting your pup in and out, but it lets in other critters too. An open hole in the door also is inefficient for your home's heating or air-conditioning bill. Build a flap for your dog door to solve these problems.
Measure the opening of the doggie door using a tape measure. Add 1 inch to the vertical measurement and jot the dimensions down. Trace your dimensions onto your rubber mat using a pencil and a straight edge. When finished, this rubber mat will serve as your new doggie door flap.
Set the mat on a surface that cannot be harmed by a knife, such as an old piece of wood. Carefully cut the rubber mat along your pencil lines using a straight edge and a utility knife. Hold your new flap up with the top 1 inch against the door and make sure it swings easily through the opening.
Place the aluminum strip across the top of the rubber mat and mark with a pencil where it needs to be trimmed. Using tin snips or a hack saw, cut the aluminum to the desired length.
Set the mat back on that old piece of wood and hold the aluminum strip across the top of it. Use your drill with an 1/8 inch bit to drill holes every few inches through both the aluminum and the mat.
Switch your drill to the Phillips head bit and set the wood screws near the door. Run a bead of silicone right above the top opening of the doggie door. Hold the aluminum strip and the mat, with the holes you just drilled still lined up, in place for installation. Drill the wood screws through the holes and into the door until they're tight. Wipe away any silicone that squeezed out during installation, and your new doggie door flap is complete.
Courtney McCaffrey graduated from the College of Charleston in 2008 with a B.A. in media studies. She has served as an editor for Blooming Twig Books and the MADA Writing Services publishing company. She is now a writer on various outdoor sports such as snowboarding, skiing, surfing and bodysurfing.