Rigid Foam Roof Sheathing

The boards are available in several thicknesses and r values.

Rigid foam roof sheathing.

1 inch and 2 inch thicknesses are common. Foamular 150 1 1 2 in. R 10 scored squared edge insulation sheathing. You might as well put the rigid foam in the branches of a tree in your back yard.

Remove existing roofing and non adhered underlayment to expose roof sheathing. If you have a vented attic it makes no sense to install rigid foam above the roof sheathing. Roof sheathing attaches to the surface of the rafters or trusses to form the structural skin of the roof. Foamular 150 1 in.

Nail it around the edges with roofing nails. A vented attic is basically outdoors so installing rigid foam above your roof sheathing is a waste of money and a waste of rigid foam. R 5 scored square edge rigid foam board insulation sheathing. Installing rigid foam insulation on top of roof sheathing is a great option for commercial buildings and homes with limited space.

Rigid insulation sheathing is made of a rigid plastic foam that is typically sold in 4 8 or 4 10 foot boards. Start at the bottom of the roof and place the first piece of rigid foam insulation against the metal flashing starting at the center line. Johns manville polyiso foam sheathing insulation boards provide a continuous layer of insulation to reduce thermal bridging and improve energy efficiency. It spans the rafters to support the roofing and in the case of panel sheathing such as plywood or osb it acts as a diaphragm with the walls to resist horizontal loads.

Many homes in more urban areas or other places with dense populations are opting for this method because they can better optimize space. Apply continuous air control membrane to existing roof sheathing or implement continuous air control at roof sheathing. Foamular 250 2 in. Not only that foam sheathing will soon be mandated by code in some climate zones.

Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers. Rigid foam over roof sheathing we are in the process of building a home with all the ceilings in the house paralell to the roof and used 2 x 10 rafters throughout. R 7 5 scored squared edge rigid foam board insulation sheathing.