Guest User
1/5/2009
Hi there. I am going to replace my 12 year old tar and gravel roof. It's full of do-it-yourself patches from previous owners, so I just want it completely rebuilt. I looked at torch-on membranes but found they too will only last about 10 years before the same patching would be needed. Here in Vancouver, a few big companies advocate metal, snap-lock and mechanically fastened standing seam, 26 gauge steel roofs instead of the torch-on membrane. I agree but I had a question as to the procedure to apply the roof. One company claims they had problems with moisture and rot on some of the first metal installations they did 10 years ago. Turns out on those, they put the metal over top of already moist shingles and plywood, which then rotter from below. To avoid this, they now use this procedure: - strip all tar and gravel off, down to the decking (in my case, tongue and groove 1 x 4). - cut a new ridge vent. - install 'donna conna' or similar sheets, about 1/2" thick, for mechanical fastening and sound, etc. - install waterproof vapor barrier on top of donna conna board. - install rubber membrane for gutters, new drains. - install standing seam metal roof panels (snap lock, 1 inch standing seam), mechanically fastened with rubber-grommet screws, and the screws are then concealed under the next metal panel seam. - add flashing and seal where needed. My roof is low sloped, 2 to 12 pitch, which I have read is about the minimum for standing seam (of 1 inch). The attic is well ventilated and well insulated with soffits running the entire length, but added venting is needed for metal so they cut a rigde vent as well. Currently, even when it's very wet outside, the attic space is very dry, so I think the venting and condensation situation now is good. My question is, in general, does this application procedure sound about right? And specifically, does there need to be any other waterproof material between the metal panels and the decking? The company says the thick vapor barrier they use will be watertight, and essentially even without the metal on, the roof will be sealed. They've done many of these low-sloped application and everything sounds about right to me, but I thought I'd check with the experts here first. Thanks. -DS
Guest User
1/7/2009
Any suggestions anyone? Have I posted a taboo question?
Guest User
1/7/2009
Snap-Lock and mechanicly seamed are two different things so make sure what our are getting is rated for the slope. As far as the rubber and gutter I am confused on that.
Guest User
1/8/2009
Thanks for the reply. Actually, the panels are just snap-lock, not mechanically seamed. The panels themselves are nailed/screwed down on one side, which is then concealed by the next panel, so no nails/screws are exposed. The rubber forms the gutter, which goes under the panel,up the slope at least as high as the eave, so that no water can back up if there's a clog. My main question has changed, and I need an opinion on just the roof pitch: For snap-lock style, 1 - 1/2" high seam, this roofer claims his snap-lock (not mechanically seamed) panel will be okay on my 2:12 pitch roof (he's given me a written guarantee). The panels will be 14' long on each side, simple roof with no valleys, just one peak running right down center. Problem is that all snap locks I see around the Web state 3:12 slope for almost all snap-lock style panels. I guess maybe since we are not in super-heavy snow/rain/wind areas, and my panels will only be 15' long, that he's confident 2:12 is good enough. Any opinions? Thanks- and sorry for the confusion.
Nate Libbey
1/8/2009
I have seen a great deal of snap-lock type standing seam done this way with no problems at all. Many of the manufacturers reccommend a 3:12 slope, but especially on panels only 15' long, you should be fine. Also you may want to ask him to provide you with a copy of the manufacturer's warranty. His warranty is most likely on the quality of the labor and leaks, where as the manufacturer's warranty is on the material itself (paint quality, fade resistance etc) The manufacturer may not cover it, then again they may. Also if you have the manufacturer's number you might want to call them.
Guest User
1/11/2009
Thanks very much Nate. I guess the companies who make the snap lock panels have to assume they would be used in the worst-case climates, like Hawaii or Florida, with rainfall and wind levels 10 times more than here. Warranty on this product is kind of standard- 10 years on the labor and 'lifetime' on the metal panel itself, which is somewhat pro-rated after 15 years. I think in a huge, 100-year type storm, other roof aspect would leak before water got over the standing seam. Thanks for your input!
Todd Miller
Classic Products, Inc.
1/14/2009
Sorry to just now weigh in on this. Nate's advice is, as always, spot on.
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