In reply to ransom:
I learned the carpentry trades in the North, however there are a few lessons I learned from Southerners.
One of them was how to shingle a roof from the top down. You never nail through, or walk on finished shingles. Here's the basic process (sorry, its gonna get a little wordy. Read carefully):
1- The shingle demo is done like normal. You rip off stuff as you can, standing on whatever you can nail through the shingles (since it doesn't matter if you damage the old shingles).
2- Do the deck repairs as needed.
3- Begin roof felt at the eave working up to the ridge, as normal. As you work your way up the roof, add toe boards as needed (usually every 3'-4'). The first toe board will be at the bottom (on top of the finished felt). These toe boards are continuous 2x4's, laid flat and nailed through the finished tar paper. Locals use 16d nails, and try to hit the rafters, but it doesn't matter much. The decking will hold them fine (because of the additional friction of the 2x4 laying flat). Then, add a 2nd 2x4 standing on edge (the same way they lay in the roof jacks), nailed to the top edge of the first (flat) 2x4. Get it? The complete toe board will be made of 2 separate 2x4's nailed together in an "L" shape. Run these toe boards continuously side to side, but DO NOT go all the way to the edge (rake). Keep about 1-1.5' away from the rake. Be close enough that you can comfortably reach the edge.
4- Continue laying felt and adding toe boards every 3-4' until you are high enough to felt all the way to the ridge.
5- Layout for shingling. Measure from the eave (like normal), but calculate the top edge of the shingle courses (every 5") all the way up the pitch of the roof, until you are above the highest toe board. This is why you didn't run your toe boards to the end. You can pull your tape measure right up the rake and mark all the way to the top, then pull a chalk line between your marks.
6- The FIRST course of shingles you will run will be above your highest toe board, abut 4' down from the ridge. It will be at your knee height, standing on the toe board. DO NOT nail this course like normal. Only nail each shingle at the very top edge (2 nails are enough).
7- The second course will be laid on top of the first, in standard shingle installation. Continue until you reach the ridge, and go ahead and put your ridge vents or ridge caps on while you are up there (if this is the 2nd side of the roof you are doing). You have now completed a swath of shingling at the top 4' or so of your roof, and you have never stepped on it.
8- Now you are ready to move downhill. Go down to the next lowest toe board (still there since you did the felt). Rip off the highest toe board, and clean things up. Begin shingling at your knees again, and repeat like step 6. The only trick here is to measure accurately down from where you left off (in 5" increments), and to count carefully. Every other course is staggered, so if all the even courses have a full tab at the right end, all the odd courses will have a half tab. If you count wrong, when you get back to the part you have already finished, you will have 2 courses in a row with the tabs in the same location, and it will leak.
9- When you get back to the top where you already finished, it is really easy to lift the shingles and tuck the lower course under them, because you nailed them at the top edge in step 6. After you finish tucking the last course in (under the first course), lift the tabs of the 2nd course (from step 6), and add the nails in course #1 that you left out in step 6. Now you have completed about 8' of width from the ridge down, without ever stepping on any of it.
10- Move downhill again, and repeat until you reach the eave. Because you installed toe boards all the way up when felting, you can easily climb up and down them, and there is always another one below you (for safety), in case you mis-step.
11- Since you put a toe board at the very bottom in step 3, you won't be able to finish the roof. The very last step is to work off a ladder, removing the bottom toe board and filling in the bottom course of shingles from the ladder.
Voila! You have shingled the ENTIRE roof without EVER stepping on the finished shingles or penetrating them with a nail, WAAY safer than roof jacks.
It's a bit slower, but MUCH safer (especially for amateurs). You will have 20 or 30 long 2x4's left over when you are done. You can build some shelving in the garage.
Hope that made sense.
