Wednesday, April 11, 2007
what i learned about roofing today at habitat for humanity
(this is all really exciting for me. if it is boring to you, then at least you can be convinced that i have found something i love.)
tar paper goes over the wood. in areas where there's lot of water, you put another kind of tar-rier paper down. flashing goes against the wall, to keep rain from going behind the shingles closest to the wall. moisture is the enemy. it's all about keeping water out of the walls.
shingles begin at the lowest part of the roof and are gradually layered up. you put a double thickness at the beginning. the overlapping is such that everywhere, the shingles are actually two thick. 4 roofing nails to a shingle. the shingles should extend a half inch past the edge of the roof. every other "layer", or course, should begin with a short shingle so that the courses are staggered and cover the gaps between shingles.
in the "valley", the crease where two slopes meet, special 'weaving' techniques ensure that the water that gathers there will be safely funneled down. avoid nailing in the valley as the nails will be more likely to rust.
elsewhere, we make sure that the courses of shingles are well-lined up, use a chalk line and a tape measure to ensure that your shingles are parallel to the edge of the roof. it's easy to get the shingles crooked. it's also easy to erase the chalk lines with your behind if you are scared to stand up on the roof.
near the top you probably will need to trim the shingles so that they stay lined up and go all the way up to the siding (we were working on a roof of a porch, so there was wall above). keep a shingle underneath the shingle you are cutting so you don't cut through and slice your nice roofing job.
the shingles we were working with are called 'architectural shingles'. they have lots of flaps at irregular intervals, so they look fancier than the simpler ones with just three flaps each. habitat for humanity doesn't go for fancy accessories but they get lots of donations and sometimes the donations are for the high end version of a product.
i had so much fun today. i didn't wear sunscreen so i'm a bit burnt. the weather was gorgeous and i was just having the best time enjoying the air. the other people are nice. my hands are a bit raw--i really need to find a pair of gloves that fit and a tool belt. they have equipment there you can borrow, but the gloves are all enormous and the tool belts are little wimpy canvas aprons that slide everywhere.