To start building a door, lay out boards according to the horizontal width of the doorway, and then nail each one to a horizontal support board laid across them at top and bottom. Finally, reinforce the door by nailing each board to an additional, diagonal piece of wood. This creates what is known as a batten door, which is commonly seen on barns and small, traditional houses.
Batten doors are simple, sturdy doors that are comparatively easy to build by hand out of wood. Because they are often used on barns, they are most often seen in sets of two doors attached to each side of a wider door frame. For this type of design, it is best to use a special piece of edging called an astragal. Attach this molding to the side of the door that generally closes last, and ensure that is wide enough to cover the gap between the two doors.
A more complicated style of door, the layered door, uses three full layers of wood. To make this type of door, cut a plywood core to the size of the finished door, and nail boards to either side to create an aesthetically pleasing door. By using tongue-and-groove boards, you can build this door without any nails showing. A layered door is very sturdy and, because of its multiple layers, very difficult to warp.
When building your own door, ensure a perfect fit by building the door slightly larger than the intended opening and sizing it down using a plane.