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.

If you nick or tear the old flashing piece then go buy a new one. Installing a new roof over shingles takes less time than tearing off the old roof. To level out an existing asphalt shingle roof rip down reduce the height of two. Good quality composite shingles can weigh 350 to 450 pounds per square 100 square feet of roofing installed.

Use the chalk line to mark the line at that spot across the roof. However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life. Looks just as good and lasts as long. Each shingle will require around 4 nails underneath the tar line and about half an inch under where the next shingle will overlap.

Mark the location of the top of the uncut shingle on the felt. Cut the existing shingles and pry up carefully. Installing new roof shingles over old effectively doubles the weight of the. Continue marking lines every five inches up to the roof ridge.

Attach with nails along the top edge of the strip. The uncut shingle should hang a quarter of an inch over the roof edge. Roofing second layer of shingles roofing. 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.

Leave the old valley flashing in place and install new over it. Has the same manufacturer s warranty. Position one of the uncut shingles on top of a trimmed shingle. Install new shingles to the lower edge of the opening.

Around an inch should do. Along the rakes install a new j channel drip edge which wraps around the old rake flashing and starter courses. Remove the cover and then nail the old shingles back down again. Do both sides first and then install ridge cap shingles over the top.

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. Manufacturers will still. The first row of shingles should overhang the drip edge of the roof. How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h.

Along the eaves install a new drip edge over the butt ends of existing shingles.