.5/12 Roof Assembly

kjenglert | Posted in General Questions on February 15, 2023 04:31pm

I am going to build a 1200 sq.ft. home with a raised heel .5/12 monotruss. This will allow me to either make an unvented assembly with spray foam flash and batt or a vented assembly with fiberglass batts, other batts, or blow in insulation. It seems to me that 0.5/12 is too low a pitch to vent properly. Is this true? Does the climate matter? This home will be in the Methow Valley which is in Zone 6 (dry). Thanks for any ideas.

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Replies

Expert Member

Michael Maines | Feb 15, 2023 04:37pm | #1
Yes that is too low a slope for venting to work effectively, unless you take the extra steps described here: https://www.greenbuildingadvisor.com/article/insulating-low-slope-residential-roofs. Vented roofs should be at least 2:12.
seabornman | Feb 15, 2023 07:28pm | #2
What will your roofing system be? You probably don't need a vented system.
rockies63 | Feb 15, 2023 08:06pm | #3
Architect Steven Baczek did a vented low slope roof in his Youtube series "The Hilltop Arrow" project.
The roof plan.
https://www.youtube.com/watch?v=88XM3Uy0hZ8
The roof eave detail.
https://www.youtube.com/watch?v=Q71RVLh_42k
kjenglert | Feb 22, 2023 11:03am | #4
Thanks for these ideas. We will be making an unvented roof.