No Sheathing Under Roof

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.

No sheathing under roof.

For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. I agree with you. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes.

I just had my site survey and they found out the tiles under our 40 yr old roof has no plywood underneath. A leak free roof membrane that is fully adhered to the roof sheathing should be installed. 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. The typical thickness range for sheathing is 3 8 to 3 4 inch.

Wood is an excellent insulator and in moderate climates no additional rigid insulation on the roof is necessary. There are two good reasons for installing roof sheathing and roofing underlayment under metal roofing. Some installers will suggest removing the tiles under the footprint of the panels and putting in plywood sheathing a waterproof membrane and shingles for that area. When open cell spray foam is used a low perm class ii vapor retarder is installed where required.

8d ring shank nails should be used instead. Zip system roof assembly combines our revolutionary integrated sheathing and flashing tape or liquid flashing to provide a sealed roof for protection against moisture intrusion during construction or if high winds strip the roof covering away. Sheathing should be a minimum of 19 32 inch thick. Commonly used as roof sheathing where a ceiling will not be installed and they will be visible from inside the house such as across beams in a vaulted ceiling.

To provide an air barrier at the top of the insulation 2. 3 benefits of rigid foam sheathing. A strong resilient roof is a home s first line of defense when the roof deck is exposed to weather. Site survey found no plywood under tile roof 03 16 2015 04 00 pm.