Rigid Foam Under Metal Roof On Purlins

We live in zone 5 suburb of chicago and are hopefully about to put rigid foam above the roof sheathing on just the northeast roof portion of our roof.

Rigid foam under metal roof on purlins.

Then a second layer of plywood sheathing and asphalt shingles following the steps explained in this article. Insulating with spray foam insulation. Use rigid foam insulation to cover wider spans of roof sheathing between joists. This foam can be used on either the outside or the inside of the sheathing.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Will that be a concern with metal roofing. First nail 1x2s to the rafter sides up against the roof strapping. Commonly these use metal deck panels over the roof structure thus supporting the insulation and a vapor retardant material on top of the deck.

This is different from the normal roll up type of insulation as it comes in panels rather than paper covered fiberglass. It is possible to insulate from below as you suggest with rigid polystyrene insulation. In this insulation approach rigid foam insulation board is used to achieve the sought after energy performance. Polyurethane spray foam metal roof insulation in order to add moisture barrier under metal roof you can spray the undersides of the roof by using a thick layer of polyurethane spray foam.

Avoids nails or screws which could penetrate the metal roof and cause leaks. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. This will provide an air space above the foam insulation to improve ventilation on the underside of the metal roofing. Plywood sheathing then roofing felt than 1 5 rigid foam metal roofing.

Metal roof purlins are installed horizontally under metal roofs. I have a 90 year old stone cottage in portland oregon. I am getting ready to put a metal roof on my house it presently has 1 layer of shingles on a 6 12 pitch and iam in florida i am think of putting r foil under 1 x 4s battens or the styrofoam boards between the battens and also a solar attic fan w elec option and the metal will be a light color from douglas metal roofing does this sound like a. Cut each sheet to the desired size using a utility knife then fasten it in place using staples or adhesive.

The best material for use with metal roof insulation is in the form of foam batting. Basically speaking ignoring sub insulated roofs which are a special case with rigid foam board insulation directly under the metal roofing the roofing needs proper support to be able to handle snow ice loads wind loads and walking on during installation cleaning and maintenance. It will help you to eliminate problems that may come when the house becomes extremely cold in the winter and terribly hot in the summer.