The big picture concern is actually more about trapped moisture than whether the substances that make up spray foam insulation will corrode steel or metal sheets.
How to apply foam insulation to a tin roof.
Cut each sheet to the desired size using a utility knife then fasten it in place using staples or adhesive.
Rigid foam boards come in different material.
Made of cushioning durable and water resistant foam materials metal roof foam closure strips can be easily fabricated to any custom.
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.
We are having a standing seam metal roof installed.
Use rigid foam insulation to cover wider spans of roof sheathing between joists.
There seem to be no chemicals in spray foam that could react with steel or the galvanized protective coverings on the metal siding and roofing panels.
Polyurethane spray foam metal roof insulation.
Some types of metal.
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.
Insulating a metal shed roof with rigid foam can be done one of three ways by laying the board prior to applying the roof by removing the existing roof and installing new foam board or by insulating the existing metal roof from the inside.
Moisture from indoors can diffuse through the foam and find the cold roof sheathing where it accumulates and eventually rots the roof.
They can also be used as cushion seals for polycarbonate roofing panels.
I am planning on installing 2 of xps ridge foam or gutex multitherm 60 r 8 7 on the exterior of the sheathing then a vapor perm wrb then furring strips at 45 degrees to attach the metal roof to and allow for drainage of any condensation.
Foam closure strips for metal roofing are specially formulated with unique wave designs for premium sealing of metal roofing panels.
Open cell spray foam insulation is risky in all climate zones we already know open cell spray foam is risky in cold climates.
Avoids nails or screws which could penetrate the metal roof and cause leaks.