Things You'll Need
6-inch or 6-inch by 6-inch or larger wood posts
2-inch by 4-inch wood boards
Router or hammer and chisel
If you want a porch roof to remain sturdy for years, the posts or columns that support that roof play an essential part. If you want to simplify the process of installing porch posts or columns, you can buy pre-made deck posts or columns from many building supply manufacturers. If you prefer a more customized design to the posts or columns or can't find columns in the appropriate size for your porch, you may choose to build the porch posts and columns yourself.
Measure the space between the porch floor and porch roof to get the height for the posts or columns. If you have no old posts or columns on the porch, you generally have no roof yet in place. In this case, measure the distance from the porch floor to the height at which you would like to place the porch roof.
Measure the depth and length of the porch. Cut enough wood posts of the length that you measured to place a post at the front corners of the porch and additional posts every 8 feet. If the 8-foot spacing gets in the way of the entrance to the porch, cut two posts to place on either side of the entrance.
Cut two blocks of wood from a post several inches larger than the post you used to create the body of the porch support. Cut a 10-inch, for instance, for a column that measures 6 inches, so you have 2 inches to work with on all sides. Make the cut blocks the depth that you would like the base of the column and the capital — or top piece — of the column to be.
Carve the base and capital pieces to the desired design, using either a router or a hammer and chisel to do it manually. Leave the side of the base or capital that will touch the porch or the porch ceiling the full width of the block of wood that you cut, and carve the design inward so the other side of the block ends up the same size as the post you made for the column. In the case of a 10-inch base and capital with a 6-inch post, for instance, carve the pieces to taper to a 6-inch circle or square, depending upon the style of post you used.
Line up the base that you create with the bottom of the post and secure it into place with four screws long enough to pass through the bottom of the base and at least 2 inches into the post. Measure the length of the post, plus the base, then measure the carved capital for the column. Cut enough length off the post to accommodate the capital so the column fits the space.
If you want simple posts, once you finish cutting the original wood posts to size, you don’t need to do any additional work. A porch roof should generally be installed several inches below a line of second-story windows or just beneath the eave on single-story house. Use either wood or round posts to create your porch posts or columns, depending upon the look you want to achieve. Generally, though, square posts are considered posts, while circular posts are considered columns.