Now here are a few things to get you started to see if you may have hail damage on your roof.
What does a roof jack look like.
Use a hammer to bend the top edge of the soft lead roof jack down into the vent pipe.
If a hailstorm has struck your area hail stone impacts will often show up.
Avoid using short pieces as the risk of a length of lumber tipping upward if you should happen to step onto the end of it is greatly increased.
A roof jack will not do you any good without planks of lumber to span them.
If you can see a dip curve or swag on the peak when standing in the street your roof has a problem.
It might be something.
Roof jacks provide a stable surface to work increasing safety and making it easier to apply roofing.
What causes a sagging roof line.
Roof lines should be arrow straight.
Also before you start installing your flashing you need to look to see if the wall in question has a corner on the roof face as in the image below.
Standard 2 by 10 inch lumber with fit into the channel on most roof jacks and should be available at any lumber yard.
What exactly does hail damage on a roof look like.
Look for dents and dings on gutters and downspouts.
Dented gutters downspouts.
You can usually feel sheathing nails which are driven into rafters through the underlayment attach a jack by driving two 16d nails never roofing nails into a rafter.
Cut roof shingles to fit around the roof jack and insert them under the existing shingles.
Ideally locate a rafter below the sheathing.
Nail the new shingles down with roofing nails so the nails are covered by the shingle above.