How to Install a Roof From Start to Finish

Install a roofing grade plywood, lumber or oriented strand board (OSB) sheathing to provide a solid roof deck for your roofing material. Install a minimum of 15-lb. roofing felt over the roof deck, in parallel rows with a 3-inch overlap up the roof.

Snap chalk lines at regular intervals from the ridgeline at the top of the roof to the eaves at the bottom of the roof to keep your roofing installation straight. Snap chalk lines as a guide for each horizontal course across the roof from each rake or side roof edge.

Install a drip edge on the lowest roof edge. Fasten valley and rake edge flashings before you install the roof material unless the roofing manufacturer instructs you otherwise. Typically use aluminum coil trim to make the flashing you need to joint between two transitions such as, between the roof and the house wall or between two different roof directions on one side of the roof.

Install metal roofing with self-tapping hex screws with washers unless your roofing manufacturer recommends a particular fastener. Use roofing nails for wood or asphalt shingles, and leave a thumbnail depth of space under the nail head to allow for material expansion.

Stagger shingle courses to lessen the risk of water penetration at side joints. Overlap shingle, slate and asphalt-based roll roofing material between courses by at least 3 inches. Follow the precise overlap instructions from a metal roofing manufacturer to keep your product warranty valid.

Install ridgeline flashing along the top roofline to extend 6 inches onto the roofing material to each side of the roof. Fasten ridge caps over the ridgeline according to the roofing manufacturer's instructions. Typically, you install each ridge cap with an overlap that faces away from the prevailing wind.