How to Apply Sheet Metal Roofing

Nail furring strips horizontally across the tops of the roof rafters. Unlike asphalt shingles, metal roofing doesn't need solid sheathing underneath it. Use 1-by-4 lumber for the furring strips, and separate them with a 4-inch space in between each one. This will save on material and also help air to circulate around the roofing.

Lay a piece of metal roofing on one side of the roof next to the gable end, with its bottom edge at the eaves. Screw the roofing onto the furring strips using 2-inch-long roofing screws fitted with rubber gaskets. Only put the screws into the ridges on the metal roofing; this reduces the risk of leaks. Put in a screw every 12 inches along the side of the sheet that runs up the roof next to the gable end and in the middle of the sheet. Leave the other side of the sheet unscrewed until Step 3.

Lay another sheet of metal next to the first so that its edge ridge overlaps the edge ridge of the first sheet. Screw the joined edges of the two sheets to each other and into the furring strip with a roofing screw driven in every 12 inches along the dimension of the metal that runs up the slope of the roof.

Continue to lay metal sheets across the face of the roof in this way until you reach the other side of the roof. If the last sheet is too wide, cut it to the proper width for the roof using a circular saw fitted with a metal cutting blade.

Lay the second course of metal sheets higher up the roof than the first if the roof is long enough that it requires more than one course. Overlap the top of the first course by 12 inches to ensure that water won't creep up between the top and bottom sheets and get into the roof.

Screw down a top cap to the ridge after you have laid all of the metal sheets on both sides of the roof.