You don’t need to be an expert woodworker or have expensive tools to make an exterior door. With some patience, attention to detail, and a few tools you likely already have in your toolshed, you can build your own door with ease.
Step 1 – Cutting and Fitting
Warning: Take all appropriate safety precautions when working with any saw, including a table saw. Wear safety glasses and follow the manufacturer's instructions.
First, measure and cut lumber for an outer frame of two 84-inch upright stile pieces. Use a table saw to cut the wood. The pieces should be approximately 4-inches wide, with a top rail of 3 1/2 inches wide and a bottom rail 8-inches wide. When fitted together, these rails and stiles should comprise a square of a standard-sized door opening of approximately 36-by-80 inches.
Cutting Rails, Mullions, and Panels
Then, cut and fit two inner horizontal rails approximately 2 1/2 inches wide. Cut two vertical mullions of the same width. If you want to, you can place panels of wood or glass between the inner and outer rails and stiles. Usually, doors are built with taller, wider panels for the bottom of the door and a single, centered safety-glass panel sandwiched between two solid wood panels for the upper portion of the door. However, how you design your door is up to you.
Step 2 – Constructing Joinery
When making an exterior door, you should make it as weatherproof and flat as possible. Therefore, you should use weatherproof glue, mortise, and tendons for joinery. Apply sufficient glue to all joints before assembling the door, and construct the door on a flat surface. Then, apply final clamps and cinch them down tightly. Allow to dry thoroughly.
Step 3 – Installing Raised Panels
After the glue has dried and you’ve removed the clamps, construct a series of raised panels and fit them between the rails and stiles of the exterior door frame. You can construct single raised panels out of thicker wood, or pairs made out of thinner wood. Use machined molding to hold the panels in place. Use glue, nails, and silicone caulking along the inside of the wood molding and glass panels for the best insulation.
Step 4 – Weatherproofing the Door
Hot sun, cold weather, and rain can take a toll on exterior doors. To protect your door from this kind of abuse and to prevent your exterior door from warping, apply a finishing coat on both sides of the door.
Begin by sanding the door with a 100-grit sandpaper, and work up to using a 220-grit sandpaper. Then, apply a primary coat of 50-to-50 ratio of wood-finishing varnish and mineral spirits. When thoroughly dry, apply two more coats of varnish. Finish the exterior door with fine-grade steel wool. Then, paint your exterior door to revamp your home's entire look.