Pete Tedder
8/27/2009
After 7 years I'm throwing in the towel on the metal roof - tearing it all off the back of the house and doing it over. THe ice daming in the winter has been killing me and flooding the house. Ice reaches as much as 24" in thickness in the valleys! I'm using McElroys's Grand rib design bolted on panels. I'm planning to coat the whole roof with Ames Research Blue max - 3 coats. Then reinstall the metal roofing that I can salvage and new metal roofing panels to complete the job. The question I have is should I leave the bottom of the panels open so air can circulate up the ribs and water, should any accumulate, will be free to flow out? I just hate the thought of trapping a water back up between the panel and the sheathing. This is the third attempt to fix this ongoing problem guys! At this point I'm beginning to feel that I should have just painted the plywood sheathing and called it a day! One more try! Roof pitch is 10/12. Help!
Ken Buchinger
NCI Building Systems, Inc.
8/27/2009
Do you have a conventional attic? If so, you definitely want to have air intake at the soffit and air exhaust at the ridge. You may also want to reinstall the metal over a batten/counter batten system that will allow for air flow between the roof deck and the metal panels. I would install something like Coravent purlinvent at the eave, which will allow for air intake. I would not leave the panels open at the valleys.
Guest User
8/31/2009
Thanks Ken, Yeah, I agree, I wouldn't leave the panels open at the ends terminating in the valleys. Those will have to be sealed. Yes we do have venting. Not really attic space but mainly cathedral ceilings with proper venting trays installed. By leaving the ends of the panels open on the runs that terminate at the eave of the house I'll be letting air flow up the panel ridges in addition to the eave vents and ridge vents. It may be the best way. I suspect any concern over bees/hornets/wasps building nests in the open ribs of the panels is silly since the temerature of those panels in the summer months is blistering! As a point of maintainance, I've got to find something that I can spray on the panels perhaps once a year before winter to keep the ice and snow from sticking. The last two years, the first snow storm of the season has been an unusual mix of freezing rain, sleet, and snow that just wouldn't let go. Everything that came afterwards just kept building up rather than sliding off.
Ken Buchinger
NCI Building Systems, Inc.
8/31/2009
Ice and snow sticking shouldn't be a problem as long as it is not melting on those "marginal" days and refreezing at the eave. The idea is to have a completely cold roof so that when it is warm enough to melt the ice and snow, it melts everywhere and doesn't refreeze at the eave.
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