Any wood door with a plain, flat face can quickly and easily be given a whole new look through the application of moldings. Almost any lumber yard or hardware store carries a large selection of inexpensive stock molding patterns that will suit any taste, and you can combine moldings for even more pattern possibilities. The look you choose is limited only by your imagination.
Begin by studying some of the designs shown here, suggested by the Wood Moulding and Millwork Producers Assn. You might also want to examine actual doors, either in magazines and catalogues or by driving around your neighborhood, to get an idea of what look you'd like to achieve. You can then try a few sketches and experiment with different patterns.
A visit to the lumber yard is next. They'll have a molding chart or a sample board that you can look at, which will show you what patterns are available and what their actual sizes are. You may wish to use only one design, or you may choose to combine two or more of them into other patterns. When actually purchasing your moldings, first determine how many feet you'll need, then add about 20% for waste at the cuts.
You will find it easiest to work on the door if it is taken off its hinges and laid flat on a pair of sawhorses. Simply remove the hinge pins, then have someone help you slip the door out of the frame. Exterior doors are very heavy and awkward, so be sure you have help.
With a pencil, a straightedge and a framing square, measure and lay out your design directly on the door. This will let you further experiment with the design and modify it as desired. When you have it exactly as you'd like it, the drawn-out design can serve as a pattern for cutting the moldings.
You will need a miter box to accurately and cleanly cut the moldings. If you only have a few cuts to make, you may wish to purchase an inexpensive miter box that can be used with any type of hand saw.
If you have a lot of moldings to install or if the cuts are at angles other than 45 to 90 degrees (the only cuts you can make on the inexpensive boxes), you may want to rent a professional-quality hand or electric miter box.
Moldings that meet in a 90-degree corner, used when forming a square or rectangle, needed to be mitered at 45 degrees on each piece. To make an octagon, where the corners are each 45 degrees, the miters are cut a 22 1/2 degrees each. Other angles can be made by simply measuring the desired angle with a common protractor, then cutting the miters at half that angle.
Attach the moldings to the door with yellow woodworker's glue (lightly sand any glossily-painted surfaces first) and small brads. If the moldings are thin or if you're nailing near the ends, pre-drill the wood to prevent splitting. Finally, set the nail heads, fill the holes with wood putty or exterior spackle, and stain or paint the moldings to match the door.