The next layer should be placed with the bottom of each shingle meeting the seam between the two shingles beneath.
How to roof a porch with shingles.
See below for a shopping list tools and steps subscr.
Then nail shingles on the new roof and exposed areas of the old roof.
Nail down loose roof sheathing to rafters.
Installing the first set of shingles you should start from the bottom of the roof and make sure that they are nailed down securely.
Staple felt every 6 to 8 inches.
Measure your roof from the bottom to the top of your porch roof plus one row your last shingles will slide under your home s shingles.
If you are renovating the roof you may want to use new sheeting anyway if the old underlay is in poor condition.
Divide that number by the length of the tabs.
If you are renovating an old roof remove the old shingles first.
Fold new shingles over the new valley onto the old roof overlapping by at least a foot.
If it is a new roof install the tar sheeting on top of the sheathing.
This gives you the number of rows of shingles you will need.
Cover roof deck with 30 pound felt underlayment.
Finish your gable roof addition tie in by installing siding to match the existing house and fascia and trim boards at eaves and edges.
The tar sheeting should be stapled in place and should cover everything to prevent any leakage.
If the porch is an open porch anyway this is not so important.
Roofing contractor jack viera demonstrates installing three tab asphalt roof shingles.
If it comes out to an odd number like 7 5 adjust the spacing to make it 8 rows.