Corrugated roofing - ends - Small Cabin Forum

- Forums - Register/Sign Up - Reply - Search - Statistics -

Small Cabin Forum / Cabin Construction / Corrugated roofing - ends


Author	Message
chrisser Member	# Posted: 13 Mar 2014 09:48am Reply I'm planning on using corrugated roofing for our cabin. I have a shack on the site that has more than enough, and the roofing is in good shape. However, it's old and the profile is different than most of the roofing currently sold at the home stores. I'm going to be using OSB under the corrugated metal, with roofing felt between. Eventually, there will be insulation under the OSB between the rafters and the eaves will be vented. Trying to figure out what to do with the edge of the roof and the area where the roofing meets the ridge cap/vent. There are some universal foam closure strips that would probably work, but I'm concerned that they might trap any water condensation under the roof and cause it to rust from the inside out. There is also something called flex-o-vent, which is a similar idea (universal expanding material) but it is air permeable. My initial thinking was that the flex-o-vent would let air under there, so it would probably let water drain out somewhat. On the other hand, letting air in there would also carry moisture. The foam strips would probably trap any water, but sealing the ridges in the panels would keep water from the ambient air out of there. It's also always possible one of my fasteners could leak slightly. I don't like the option of leaving the ridges open - too many insects in the area. Last thing I need is a bunch of wasps or bees living under the roofing. Is there an accepted best practice for corrugated metal?

Atlincabin Member	# Posted: 13 Mar 2014 06:00pm Reply I don't know about "accepted best practice" but you definitely want some venting of the roof, otherwise you likely will end up with water and ultimately corrosion. If you look on some of the tin roof manufacturers' websites (you gotta look hard sometimes) they usually have some sort of air permeable but insect-proof material that is used at the tops and bottoms of the roof. Typically, this is some sort of hard plastic stringy-netting stuff (think of it as 3D screening) that is custom-fit to their metal roof profile (you need different stuff for the tops vs bottoms vs gable ends). The stuff I used on my roof was flexible enough that it could probably be used on other similar styles of roof metal, so I would guess that you might be able to find something that is close enough to your profile to work. One reason for having felt under the metal is to allow any water that gets in there to drain off the roof rather than percolate into your insulation etc. so I doubt you will trap too much liquid moisture. But you still want the venting to allow the really humid air to get out. I wouldn't worry about closing in the edges (gable end edges) of a metal roof. Airflow should go in the bottom (drip) edges and move up under the roof to the peak, and exit at the peak. Thus the need to have insect barriers at both the bottom and top ends of your roof. Greg

MtnDon Member	# Posted: 13 Mar 2014 06:19pm Reply Fabral (metal roofing mfg) Installation Guide

albert147 Member	# Posted: 19 May 2017 11:07am Reply chrisser Quoting: chrisser I'm planning on using corrugated roofing for our cabin. I have a shack on the site that has more than enough, and the roofing is in good shape. However, it's old and the profile is different than most of the roofing currently sold at the home stores. I'm going to be using OSB under the corrugated metal, with Expert outer banks gutters felt between. Eventually, there will be insulation under the OSB between the rafters and the eaves will be vented. Trying to figure out what to do with the edge of the roof and the area where the roofing meets the ridge cap/vent. There are some universal foam closure strips that would probably work, but I'm concerned that they might trap any water condensation under the roof and cause it to rust from the inside out. There is also something called flex-o-vent, which is a similar idea (universal expanding material) but it is air permeable. My initial thinking was that the flex-o-vent would let air under there, so it would probably let water drain out somewhat. On the other hand, letting air in there would also carry moisture. Hello, I think using foam to insulate your cabin roof is very nice and effective way to make your roof so usage.