No Sheathing Under Roof

Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.

No sheathing under roof.

It is nailed directly to the rafters. 8d ring shank nails should be used instead. The current state and local building codes for the minimum r value of air impermeable insulation required for the roof assemblies in the home s climate. Modern metal roofs are expected to last 30 years or longer.

If you re wondering how to prevent condensation under a metal roof you re not alone. Sheathing should be a minimum of 19 32 inch thick. While metal roofing doesn t require plywood underlayment there are circumstances in which you may wish to install plywood to anticipate future roofing needs or to offer additional soundproofing. A leak free roof membrane that is fully adhered to the roof sheathing should be installed.

3 benefits of rigid foam sheathing. Owners of agricultural buildings man caves and horse barns all are worried about the corrosive effects of condensation. Never attach roof sheathing with staples. More effective insulation with r values ranging from 3 6 to 8 0 rigid foam sheathing has much better insulation per inch than other materials i e.

How to prevent condensation under a metal roof. July 28 2017. When open cell spray foam is used a low perm class ii vapor retarder is installed where required. Plywood has an r value of 1 25 and fiberglass batts have an r value of 3 14.

Sheathing is installed perpendicular to roof trusses.