Rigid Foam Roof Sheathing

Johns manville polyiso foam sheathing insulation boards provide a continuous layer of insulation to reduce thermal bridging and improve energy efficiency.

Rigid foam roof sheathing.

Detail roof wall intersection and all openings and penetrations to provide a continuous air barrier system. You can even place it under the foundation slab. Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers. Choose rigid insulation wisely and consider the effect its characteristics will have on the performance of the your project overall product cost and the best way to get the bang for your buck.

One of the keys to over roofing is to tie the air control layer of the roof assembly to the air control layer of the wall assembly. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. Cold formed metal framing c. On the gable ends this was pretty easy.

Exterior rigid foam improves air tightness adds r value reduces the chance of condensation in wall cavities and greatly reduces thermal bridging through studs. Rigid foam insulation packs a lot of r value into a thin package but not all rigid foam performs the same. Install nailbase for cladding. Air barrier system 4.

Rigid insulation provides thermal protection and it can also serve as an air and moisture barrier. Rigid foam insulation also known as insulating boards provide high r values. Alterations to roof ceiling wall or floor cavities which are insulated to full depth with insulation having a minimum nominal value of r 3 0 in. Replacement of a roof membrane where either the roof sheathing or roof insulation is not exposed or if there is existing roof insulation below the roof deck.

Metal panel on metal framing figure a 1. Polyiso consists of a uniform closed cell polyisocyanurate foam core and provides one of the highest r values per inch of any rigid insulation. The boards are available in several thicknesses and r values. Rigid foam sheathing 3.

Rigid insulation sheathing is made of a rigid plastic foam that is typically sold in 4 8 or 4 10 foot boards. This foam is applied over the top of the membrane that came down from the roof deck catching the wall control layers. Install it anywhere from the roof to the foundation. 1 inch and 2 inch thicknesses are common.