Residential Oversheathing Roof Insulaiton

This concept while not new has become more accepted in recent years and is being used in residential construction.

Residential oversheathing roof insulaiton.

Residential roof insulation insulfoam offers a wide variety of faced laminated and standard high performance eps insulation products for all your new and re roofing needs. Don t let your heating costs go through the roof. Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. Over roof insulation the gable overhang has been cut flush with the wall sheathing.

With this kind of roof the insulation follows the slope of the roof. The boards are available in several thicknesses and r values. However most cathedral ceilings and low slope flat roofs are insulated roof assemblies. A roof over a vented unconditioned attic does not need to include any insulation.

Rigid insulation sheathing is made of a rigid plastic foam that is typically sold in 4 8 or 4 10 foot boards. Moisture generated indoors or that infiltrates into the home is responsible for the bulk of the moisture in an attic insulated with spray foam on the underside of the roof sheathing. For more information on this option see installing mineral wool insulation over exterior wall sheathing. It s not coming from above the roof and it s not some new moisture source resulting from the spray foam.

R panel is manufactured with a closed cell polyisocyanurate foam core bonded to fiberglass reinforced facers and designed for use over metal nailable and non nailable roof decks with a variety of membrane systems. Continuous rigid insulation is a construction solution that provides a thermally efficient building enclosure. Nail it around the edges with roofing nails. Install insulating sheathing above the roof deck on existing homes.

If you prefer not to use rigid foam you can use mineral wool panels instead. This retrofit assembly is appropriate for homes with conditioned attics or where the retrofit is intended to create a conditioned attic. Lstiburek takes blame for bad language. In cold climates the use of exterior rigid insulation sheathing boards has been a method of increasing thermal performance of the enclosure as well as a means of reducing the condensation potential within exterior wall assemblies.

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. Remove existing roofing and non adhered underlayment to expose roof sheathing. 1 inch and 2 inch thicknesses are common.