Thanks folks, I appreciate the responses. Next question: I'm new in the house, but I'm going to guess the shingles are in the 10 year old range, although they look in pretty good shape (and the house inspector said they were in pretty good shape also, for whatever that's worth). Still, they are old. Anything I should be careful and do when cutting them? Also, what sort of sealant(s) or glue(s) or mastic(s), if any, should I put down: between the flashing and the decking? between the shingles and the flashing? between the shingles I've lifted that will lay back down over the surrounding shingles? I should mention I live in Anchorage Alaska, and it's near end of summer and cool (in the 60's going to get cooler, not warmer). We're at the time of year where it's going to start raining soon, then go to october, when it turns white. So if I'm going to do it this year, I need to get on it. Thanks! Thanks!