How To Install Roof Shingles Over Existing Shingles

Install new shingles to the lower edge of the opening.

How to install roof shingles over existing shingles.

Good quality composite shingles can weigh 350 to 450 pounds per square 100 square feet of roofing installed. Mark the location of the top of the uncut shingle on the felt. Installing a new roof over shingles takes less time than tearing off the old roof. Installing new roof shingles over old effectively doubles the weight of the.

This provides added protection against ice dams. Each shingle will require around 4 nails underneath the tar line and about half an inch under where the next shingle will overlap. Along the rakes install a new j channel drip edge which wraps around the old rake flashing and starter courses. Use the chalk line to mark the line at that spot across the roof.

Manufacturers will still. Along the eaves install a new drip edge over the butt ends of existing shingles. If you nick or tear the old flashing piece then go buy a new one. However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life.

Remove the cover and then nail the old shingles back down again. Chances are your roof structure was designed for a dead load of one layer of shingles plus extra for snow and a safety margin. Attach with nails along the top edge of the strip. The uncut shingle should hang a quarter of an inch over the roof edge.

How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h. Around an inch should do. To level out an existing asphalt shingle roof rip down reduce the height of two. Do both sides first and then install ridge cap shingles over the top.

Use a starter strip or cut pieces for a starter course. Leave the old valley flashing in place and install new over it. The first row of shingles should overhang the drip edge of the roof. Looks just as good and lasts as long.

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. Has the same manufacturer s warranty. Roofing second layer of shingles roofing. Cut the existing shingles and pry up carefully.

As long as it s done right and under the right conditions installing new shingles over old ones can last as long and look just as good as a complete re roof.