How To Install New Roofing Shingles Over Exisyting Roof

Nail the drip edge in place using your hammer and roofing nails.

How to install new roofing shingles over exisyting roof. Attach with nails along the top edge of the strip. Cut the flashing into 6 to 8 foot lengths to help prevent buckling after installation. Install new shingles to the lower edge of the opening. Apply roofing cement to the back.

Leave the old valley flashing in place and install new over it. Because asphalt shingles are routinely exposed 5 in rip down the first strip the starter course so that it is 5 in. To level out an existing asphalt shingle roof rip down reduce the height of two courses of shingles as shown in the drawing below. Always install flashing around a chimney and other valleys where two roof planes meet as these areas are more prone to leaks if not protected.

Rip cut the starter strip or starter pieces so that they butt up against the second course of existing shingles and are even with the front edge of the existing roofing. Remove the cover and then nail the old shingles back down again. Current shingles are curling or in bad shape the new shingle roof should lay flat on your old one. You re better off removing the old roof.

To install line the valley with underlayment secured with roofing cement. But if the current roof is curling this isn t possible. Cut the existing shingles and pry up carefully. Use a starter strip or cut pieces for a starter course.