The process of putting down shingles involves placing a shingle, flap side up, on the edge of the roof and nailing a layer horizontally across the line of the roof. Subsequent layers are applied in a staggered pattern, flaps down. Each succeeding layer is overlapped until the peak is reached. There are some things you must work around on your way to the peak.
PIPES, AIR VENTS, STACKS AND CHIMNEYS
A skillful or copious application of the utility knife, flashing and tar is the only way around the roof's obstructions. Cover the upper section of pipe or vent flashing with shingle flaps, but keep the lower part uncovered. Smear tar under and over any point where there is a possibility of a leak.
In spite of the obstacle they represent to the rapid deployment of shingles, think of vents and other obstructions as your friends. They can be used as props to support nail cans, extra hammers, tools, loose shingles, etc. The plumbing vent pipe is particularly handy. It is usually anchored well enough to support a man's body weight if he happens to find himself unexpectedly surfing nearby.
The vent pipe is also a direct link with the sewage system. It can be used for the disposal of any item you might consider putting in a toilet. In this capacity, it can save unnecessary trips into the house that might result from slugging down one too many bottles of Gatorade.
The most disagreeable and embarrassing part of roofing is the flashing. Flashing is done in roof valleys, against dormers and against walls abutting the roof. It can be an awkward job depending on whether you use a safety harness and the size of part you intend to flash. Try to flash as much surface area at a time as possible. The larger the piece, the better the integrity of the roof.
The key to a successful flashing job is to cover the entire crack. With a utility knife, cut the shingles so that they do not quite come together at the crotch. Then place tar along the edge of the shingles. This will go a long way to help avoid seepage.
CAT ON A HOT TIN ROOF
Roofing is hot work. The beating sun seems to be magnified forty or fifty times. This is both a matter of proximity to the sun and of a shingle's ability to absorb heat. (This is why the attic is always hot in the summer.)
Besides drinking plenty of fluids, there is no good way to beat the heat of shingling. You must face the prospect of a perpetual hot foot seeping up through the soles of your shoes and between your sweaty toes. Keep your shirt on your back; stripped to the waist, you will turn into a human lobster: buttered, boiled, and ready for peeling.
Hot roofs are notorious for fomenting a condition known in medical circles as "blister butt". It is caused by sitting and scootching on hot shingles, tar paper, and sheathing. The malady's title fully describes the symptoms. (No need to check the medical encyclopedia on this one.) The best cure is finishing the roofing job, exposure to an ice pack and a thorough rubbing with a mixture of cold cream and Preparation H.