How to Build a Small Gabled Porch Roof

Construct a framework or walls on which the roof will sit if these features are not already present on your porch. A gabled porch roof is usually supported by being connected directly to the house on its back end and by a post in each corner on its front end.

Decide whether you will build the framework of the roof using rafters or trusses. Rafters are single boards that are installed at an angle on-site. Trusses are triangular structures that are manufactured off-site and then installed whole to create a framework for the roof. Trusses are faster than rafters, but also more expensive.

Install an eave board on each side of the porch. The eave boards are supported by the porch posts at their fronts and by being attached to the house at the back.

Install the rafters or trusses on top of the eave boards so that, looking up at them from below, the rafters or trusses are supported by the eave boards at each end. In other words, the rafters or trusses extend across the porch from one eave board to the other. Rafters should be built with a ridge board sandwiched between their top ends that defines the location of the roof peak. Trusses are installed without a ridge board, and are stabilized by nailing in braces between them.

Sheath over the top of the rafters or trusses with one-half-inch-thick roof sheathing plywood. Rather than cutting the plywood to size at the edges of the roof, install it with extra overhanging, then trim it all to size at the same time. This is faster and more accurate.

Cover the sheathing with tar paper. Tack the tar paper down with a staple gun.

Cover the tar paper with asphalt shingles, beginning at the eaves and working upward toward the peak.