Spray Foam Over Wood Purlins Metal Roof

But a preinstalled membrane may be even more effective at removing condensation.

Spray foam over wood purlins metal roof.

The problem with using. 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. It has red iron main frame with all 2x6 wood framing 16 on center on walls in between i beams and 8 steel purlin on roof. Of course everyone looks for an out when it comes to warranties and the reality is a good warranty protects the seller manufacturer far more than it.

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. The insulation then attaches to the underlayment and should you ever have to remove a piece of metal for whatever reason you do not destroy the. This type of assembly is designed to dry to the interior so the assembly should never include an interior polyethylene vapor barrier. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes.

To help with energy conservation and noise pollution many office buildings and homes use metal roof insulation as a way to cut down on these issues. Traditionally we ve insulated the roof panel to try and keep the temperature on the panel from reaching the dew point. For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. Another thought if you plan to spray foam insulation onto the underside of a metal roof on purlins install some type of underlayment tyvek etc over the purlins before applying the metal.

Install a layer of closed cell spray foam against the underside of the steel roofing or roof sheathing and fill the rest of the purlin cavity with an air permeable insulation. We ll add a vapor barrier so the moist air does not flow up through the insulation and condense on the roof. Personally i am hard pressed to see how it is the application of closed cell spray foam insulation on the interior of the steel roofing would influence the life of coatings on the exterior. My plan was to have spray foam sprayed directly on the tin sheets.

Siding and roof are tin sheets. The metal roof has been a very popular roofing material for some time but people have just started using insulation within the roofing system as a means to block out sound and keep heat in.