Guest User
3/19/2015
Last summer I installed a metal roof on my mobile home. Did all my research and thought I had it all figured out. This winter during a freezing period I experienced condensation moister leaking through my vapor barrier. I laid 30# felt over plywood decking then ran 7 rows of 1x4 the length of the roof. Then the metal roofing attached to those. What did I do wrong? Im guessing I will have to redo the whole thing this summer?
Todd Miller
Classic Products, Inc.
3/20/2015
Thanks. I am sorry to hear this. May I ask where your vapor barrier is and what is it? Also, is there any way to add ventilation in the attic space?
Info @windowsonwashington.net
An informed customer is our best customer.
3/21/2015
Is there an attic? What type of space and layout are you working with?
Guest User
4/2/2015
This is a 1980 double wide mobile home. It has a small attic area and it vents from the ends by design. I am attaching some photos. I have #30 felt down on the plywood decking then the 1x3 runs directly to the felt. the metal roofing to that. I think my mistake is that I do not have adiquit air flow and the moister barrier is not water tight due to the runners being fastened to the felt.
Todd Miller
Classic Products, Inc.
4/2/2015
I would suggest removing things down to the felt, installing a synthetic underlayment over it (or removing the felt and installing ice and watershield in place of it), then install vertical battens over the decking followed by your horizontal battens. You can then vent the vertically oriented chamber that results. You also may consider an exhaust fan in one of the gable vents to help increase air flow in the attic.
Guest User
4/2/2015
Thanks for the plan! I was thinking along the same lines. You confirming makes me feel a lot better about it. Scott
jay hewitt
8/19/2015
I have a vaulted ceiling that gets moisture damns in the winter then melts in spring when warms up i have t&g on the in side then a 6 mil vapor barrier then r38 fiberglass insulation framed with 2x10's with osb followed by 30 lb felt with asphalt shingles. I'm wondering the best way to vent the roof to give more air flow i have a full ridge vent on peek with ample venting in the soffit. do i need to remove all the roof down to trusses? or can i remove shingles,felt paper and furring strips on top of existing osb then finish with a new metal roof? any input would be greatly appreciated
Todd Miller
Classic Products, Inc.
8/19/2015
Jay, a great deal depends upon what type of metal roof you install. However, yes, you could put down underlayment over the shingles, vertical battens, and then horizontal battens (or decking) followed by the new roof ... and vent the resulting cavity with a ridge vent for exhaust and an intake vent at the bottom.
Info @windowsonwashington.net
An informed customer is our best customer.
8/21/2015
Todd nailed it for you Jay. You can remove the decking and airseal the back of the vapor barrier with some spray foam if you really want to seal up the home. The above deck vent idea that Todd put forth is probably perfect for your application though. http://buildingscience.com/documents/insights/bsi-046-dam-ice-dam

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