I"m having troubles with the roofing contractor who just did a reroof on my woodworking shop, and he's botched the flashing job required by an attached greenhouse to the building. The greenhouse has a small hinged roof section at its apex that sits on top of the main structure's roof at the main structures eave like a 22 foot long skylight. That roof section is canted slightly so it drains out the end of the building. i originally flashed it using a full length (22 feet)aluminum flashing made to sit on top of the existing shingles, lapped under them at its top, about 18" up the 6/12 pitch roof and then climb the curb of the greenhouse roof and overhang the greenhouse roof a few inches. This flashing was covered with an acrylic coating over canvas from these guys http://www.conservationtechnology.co...g_acrylic.html
and worked well if I renewed the acrylic every couple years. If I didn't the roof leaked into the greenhouse in ice dam conditions (I live in western Mass). The replacement flashing the roofer did used three 8 foot long sections lapped over eachother, and only climp up the roof about a foot. The shingles are applied over it in the usual fasion. He also used ice shield under the flashing, adhered to the plywood roof deck before usiong the aluminum flashing. His job leaks in regular rain, the way mine did in ice damning conditins if i hadn"t reneweed the acrylic for a couple years.
He wants me to pay him to repair it, but I don't think he knows what he's doing, and I'd rather repair it myself or pay someone to do it correctly, if that's possible at this stage. His plan is to use a wider piece of aluminum sitting on top of the shingles for the last third of the roof, the part that's leaking. Shouldn't this have been flashed with a single piece, full length flashing rather than in three 8 foot lengths? Can any effective metal flashing be done at this point?