Insulate A Roof Without Sheathing

We did new unfaced batt insulation sheathing wrb and exterior rigid xps foam insulation with a lot of attention to air sealing.

Insulate a roof without sheathing.

Insulated roof assemblies can be vented or unvented. Featuring integrated moisture air and thermal protection zip system r sheathing completely reimagines traditional wall assemblies by streamlining exterior water air and thermal management. Zip system r sheathing is the simple all in one structural panel with built in exterior insulation. However most cathedral ceilings and low slope flat roofs are insulated roof assemblies.

The old insulation barely filled half of the stud cavity depth. Baffles establish a channel for air to circulate between the insulation and the roof sheathing. With this kind of roof the insulation follows the slope of the roof. For such constructions the principles and benefits of unvented attic construction are similar to that occurring in a single family residence.

Polyurethane foam has the added benefit of sealing air leaks but you shouldn t consider installing it directly against the back of the siding. By leaving an air space between the insulation and the sheathing we can have air flow over the framing. As with attic floor insulation moisture and heat removal are the reasons for creating proper air. For diy attic insulation you ve got two choices.

If there is a leak the air flow ventilation will help dry out the moisture. Also note that a new fully adhered membrane is installed on the original roof deck replacing the one installed 17 years ago is folded down to catch the top edge of the wall water control layer. Both can be added to uninsulated attics or layered over existing material. Over roof insulation the gable overhang has been cut flush with the wall sheathing.

Loose fill or batt the common term for blanket insulation. A roof over a vented unconditioned attic does not need to include any insulation. The new walls came in with an r value just under 30. The solution is not to ignore the insulation but to add one component.

This ventilation offers another benefit.