How To Install Roof Shingles Over Existing Shingles

Chances are your roof structure was designed for a dead load of one layer of shingles plus extra for snow and a safety margin.

How to install roof shingles over existing shingles.

Installing new roof shingles over old effectively doubles the weight of the. Cut the existing shingles and pry up carefully. Along the eaves install a new drip edge over the butt ends of existing shingles. Each shingle will require around 4 nails underneath the tar line and about half an inch under where the next shingle will overlap.

However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life. Mark the location of the top of the uncut shingle on the felt. Has the same manufacturer s warranty. Manufacturers will still.

The uncut shingle should hang a quarter of an inch over the roof edge. Installing a new roof over shingles takes less time than tearing off the old roof. Looks just as good and lasts as long. If you nick or tear the old flashing piece then go buy a new one.

Around an inch should do. Use the chalk line to mark the line at that spot across the roof. Some roofers install a layer of waterproof shingle underlayment wsu over the existing shingles at the eave end as would be done for a roof laid on bare sheathing. 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.

Continue marking lines every five inches up to the roof ridge. How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h. The first row of shingles should overhang the drip edge of the roof. Attach with nails along the top edge of the strip.

Roofing second layer of shingles roofing. Position one of the uncut shingles on top of a trimmed shingle. Use a starter strip or cut pieces for a starter course. Along the rakes install a new j channel drip edge which wraps around the old rake flashing and starter courses.

Leave the old valley flashing in place and install new over it. Do both sides first and then install ridge cap shingles over the top. This provides added protection against ice dams. To level out an existing asphalt shingle roof rip down reduce the height of two.

Remove the cover and then nail the old shingles back down again.