How to Trim a Gable Roof

Install basic gable trim with 1-by-6 or 1-by-8-inch boards. Cut an angle with a circular saw on both boards at the peak -- it will vary with the pitch or slope of the roof. Measure the length of the rake with a tape measure from peak to the outside of the eave or overhang. Cut an equivalent angle on the eave end and leave that open or extend it over a fascia or facing board from the outside edge of the roof.

Extend the gable trim past the eave, as an alternative, and cut a decorative wedge or fish tail into it. Nail the trim board to the facing on the outside rafter of the house. Use galvanized nails and a hammer and space nails about a foot apart. Add a 1-by-2-inch or other molding at the top of the basic trim board. Place trim boards flush with the edge of the roof decking.

Add gingerbread or other decorative elements as desired. Put an ornate triangle at the peak, run wooden scrollwork down the bottom of both rake slopes or use more elaborate decorative trim that extends from the peak to the bottom of the gable outside the house wall. Nail or screw these into place with a screw gun -- most are manufactured to roof specifications and come with installation instructions.

Use either wood or vinyl for gingerbread, Victorian or other elaborate trim elements -- wood is the traditional material but vinyl has become popular because it is easier to make into ornate designs. Choose a style from a catalog to match the house -- a one-story Craftsman house looks fine with basic trim boards, two-story or story and a half houses may be greatly enhanced with trims that extend down the gable face.