Foam Insulation Above Metal Roof

Your metal roof expands when it s hot and contracts when it s cold.

Foam insulation above metal roof.

Combining foam and metal roofing. Metal roofing manufacturers typically extend a 25 year warranty. Compared to the fiberglass batts this insulation is much better. Foam insulation can be used in existing roof structures.

Remove existing roofing and non adhered underlayment to expose roof sheathing. 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. 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. The spray can be basically applied on top or bottom of the metal roofing surfaces.

The challenge comes when you combine systems spraying foam onto the metal roofing itself. This is a form of polyurethane insulation which r value is determined by the inches. Most of the time extreme heat shifts cause that leak. A spray polyurethane roof can be installed over a leaking metal roof.

Since spray foam is monolithic and closed cell it will create a watertight barrier over the entire metal roof. Financially speaking this spray is a great option especially when you need to renovate your roof after the application. It s not coming from above the roof and it s not some new moisture source resulting from the spray foam. They are used in commercial and residential structures to protect against weather and other exterior elements.

This is different from the normal roll up type of insulation as it comes in panels rather than paper covered fiberglass. Metal roofing is one of the most durable and long lasting roof materials on the market and can easily last for decades with little maintenance. This foam can be used on either the outside or the inside of the sheathing. You can add insulation to an existing metal roof by going into the attic and stapling a foil barrier to the rafters.

If the shiny side of the barrier faces the roofing hot air will circulate in. It s effective at preventing condensation and rodent infestation. The concern of manufacturer mbci is over who is going to verify that the foam will not cause corrosive damage over time to the roofing. The best material for use with metal roof insulation is in the form of foam batting.

If you have a vented attic it makes no sense to install rigid foam above the roof sheathing. Metal roofs are made from steel copper or aluminum panels. Polyurethane spray foam metal roof insulation. This retrofit assembly is appropriate for homes with conditioned attics or where the retrofit is intended to create a conditioned attic.

Install insulating sheathing above the roof deck on existing homes.