I would buy some new plywood You will be able to bad plywood thru the shingles... especially 20 year shingles.
replace it
88 sheets of plywood provided that standard size sheets are used(4ft x 8ft)
1/2, 5/8, 3/4 depending on what it needs to do.
That is 6400 square feet. You need 1 square for every 100 square feet. So, 64 squares IF you used 100% of the plywood.
Tar paper is used as a moisture barrier between the plywood decking and the roofing materials.
First you need to determine where the leak is coming from. Unfortunately this is difficult to do when it is not raining. Once you determine where the leak is coming from, you will need to remove the shingles in the affected area. Depending on the extent of the damage to the roof, you may need to replace plywood in addition to the roofing paper and shingles.
This can be a warped rotor or tire out of balance. If it only happens when braking it is a warped rotor.
well, first throw it away then buy a new one.
Strip off the old roofing and decking and replace it with thicker plywood, then apply the asphalt paper and re-shingle.
As an experienced homebuilder, I would say that the plywood should also be replaced down to the roof trusses. This is because the glue in plywood over time can break down and cause the roof to be weak. Also, old plywood often gives the home an old smell. Plywood and waferboard are inexpensive right now, so even though it's a pain to pull up the old roofing material, it will be worth the effort. The roofing felt is dirt cheap and has probably partially deteriorated with heat and cold so it should also be replaced
First you would need an extension ladder to reach the roof. To fix the whole, you would need roofing shingles, roofing nails/screws and assorted tools (saw to cut shingles, drill, hammer, screwdriver, etc).
To "hold down" loose shingles, metal roofing, loose boards, particle board, plywood, plastic sheeting, tarps, etc.