How best to handle chimney and vent pipes

I hope this is the right forum for this ??. I am contemplating putting on a metal roof. Flashing the chimney and vent pipes seem to be a big issue. Of course, few manufacturers mention anything about that in their literature. (Why is that? Because it is such a problem?) Anyway, some roofers, because I live in Maine, have suggested building a cricket on the up side of the chimney to force the snow to fall to the sides, and to make it easier to flash the roof on the up side (2 sloped valleys rather than the blunt one where the roof meets the chimney). Others have suggested just putting a steel framework to do the same job on top of the metal. As for round vent pipes, there doesn't seem to be much concensus (and in truth considering all the hassles with vents, hip coverage, and ridge vents, I am really considering going back to shingles). Any suggestions? Thank you
Todd Miller
Classic Products, Inc.
9/8/2005
Richard, I think that most people who have worked much with residential metal roofing will agree that cricketing chimneys is wise, especially in ice and snow areas and if the chimneys are more than 18" wide. At that point, you are dealing with valleys. My suggestion is to sawcut into the chimney and then flash down the sides and under the metal roofing. As for vents and pipes, there are a couple of styles of pipe flashings which work well with many metal roofs. Dektite flashings work well with most vertical seam products and Oatey flashings can work well with most shingle style metal roofs. You are correct in that flashing and details on metal roofing is not a "consensus" thing necessarily. That is because tehre are so many types (profiles) of metal roofing and so many manufacturers. What works well for one product will not work well for another. However, if a manufacturer of metal roofing has a serious commitment to the residential side of things, they will have very detailed instructions for how to properly flash their products. The key is to choose a residential product and a serious-minded manufacturer. The Metal Roofing Alliance is made up of manufacturers who I believe fit that bill. Much of what we're all about here goes beyond just consumer awareness to making sure that the right products are chosen and installed properly on each job.
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