Guest User
1/17/2016
I have recently had a Metro cottage metal roof installed and have a vaulted ceiling in one of my rooms. I am wondering how to insulate it properly. The Metro roof is "vented" do to its 3 dimensional design and has air flow under it. My roof construction in the vaulted room is ( from top to bottom ) Metro Cottage tiles, titanium underlayment, 1x4 skip sheathing, 2x4 rafters ( it is a 1950's ranch house ), and finished on the interior with drywall. I will be removing the drywall and replacing it ( redoing the electrical ) and want to insulate it properly while I am doing it. Does anyone have some input on how to insulate it properly? I am in southern california fyi.
Todd Miller
Isaiah Industries, Inc.
1/17/2016
You could add closed cell spray foam or fiberglass batt insulation. If you add fiberglass, I would also add a vapor barrier.
Guest User
1/18/2016
Thanks Todd, I was thinking of using Roxul comfortbatts instead of fiberglass or closed cell foam. Do you think a vapor barrier is still needed? Out here in SoCal, I hardly ever see vapor barriers. I was also thinking of adding 2x2's to the 2x4 rafters so I can use the thicker Roxul to get R23.
Eric Novotny
An informed customer is the Best Customer!
1/19/2016
While the temperature extremes aren't such that condensation is a big issue in your region of the country, if you insulate that roof and don't incorporate some sort of vapor control layer, you are going to have condensation. CC SPF, at the right depth provides both the insulation/air barrier as well as the vapor control layer.
Guest User
1/21/2016
Attached is a rough quick drawing of my assembly. Attached is also a link to the underlayment that was used. http://www.interwrap.com/Titanium/udl_50_main.html So a vapor barrier should go on the under side of the 2x4 rafters and under the new drywall? Thanks in advance...
Eric Novotny
An informed customer is the Best Customer!
1/22/2016
Where is the titanium in this picture? Under the 1x4s? Jeff...based on your location, you don't need an interior vapor barrier.
Guest User
1/22/2016
Eric, The Titanium is under the Metro Cottage shingle and on top of the 1x4's.
Eric Novotny
An informed customer is the Best Customer!
1/22/2016
No need for a vapor barrier. Hopefully something is on the roof deck and/or the 1x4s have some drainage cuts in them to allow for the moisture to drain by them.
Guest User
1/22/2016
There is no solid roof deck... just the 2x4 rafters, the 1x4 Skip sheathing, The titanium and then the Metro Cottage.
Eric Novotny
An informed customer is the Best Customer!
1/22/2016
The titanium will function as the vapor barrier at the roof.
Guest User
1/22/2016
Thanks Eric, So just insulate between the rafters and finish it off with drywall and I should be good?
Eric Novotny
An informed customer is the Best Customer!
1/22/2016
Yes. Make sure the drywall is good and airtight. If you are at all concerned, you can look into a product called Mem-Brain. http://www.certainteed.com/products/insulation/mold-prevention/317391
Guest User
1/24/2016
Thanks Eric, I will check out the Certainteed website....

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