Around an inch should do.
How to install roof shingles over existing shingles.
To level out an existing asphalt shingle roof rip down reduce the height of two.
How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h.
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.
Use the chalk line to mark the line at that spot across the roof.
Installing a new roof over shingles takes less time than tearing off the old roof.
Use a starter strip or cut pieces for a starter course.
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.
However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life.
Good quality composite shingles can weigh 350 to 450 pounds per square 100 square feet of roofing installed.
Continue marking lines every five inches up to the roof ridge.
The uncut shingle should hang a quarter of an inch over the roof edge.
Chances are your roof structure was designed for a dead load of one layer of shingles plus extra for snow and a safety margin.
Leave the old valley flashing in place and install new over it.
Has the same manufacturer s warranty.
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.
Install new shingles to the lower edge of the opening.
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.
The first row of shingles should overhang the drip edge of the roof.
If you nick or tear the old flashing piece then go buy a new one.
Along the eaves install a new drip edge over the butt ends of existing shingles.
Installing new roof shingles over old effectively doubles the weight of the.
Attach with nails along the top edge of the strip.
Remove the cover and then nail the old shingles back down again.
This provides added protection against ice dams.
Along the rakes install a new j channel drip edge which wraps around the old rake flashing and starter courses.
Cut the existing shingles and pry up carefully.
Mark the location of the top of the uncut shingle on the felt.