Hot Roof Closed Cell Spray Foam

Since you have already arranged to have 2 inches of closed cell spray foam installed in your floor assembly it seems clear that there is at least one insulation contractor in your area who is willing to install closed cell spray foam.

Hot roof closed cell spray foam.

Since it s air impermeable spray polyurethane foam can be installed alone on the underside of roof sheathing. Will i be looking at any problem with going to a metal roof. And again to reiterate hot roof or hot attic assemblies where the foam is beneath the roof deck are okay. With two strategies employed the airtight vapor impermeable foam plus the ventilation as a safety valve you might call this a belt and suspenders approach to building.

Todd miller isaiah industries inc. If you wish to believe a certain manufacturers claims just one of many bogus ones and install an open cell product make sure it has a vapor barrier sprayed to the foam. This roof assembly is often referred to as a cold roof and is the antithesis of a hot roof. Murmurs and hearsay about open cell spray foam insulation have been gaining traction for a while.

Not long ago someone even told me that in florida roofing companies won t let their workers go up on roofs with open cell spray foam because the roofs are so spongy the guys fall right through. Closed cell spray foam uses blowing agents with a high global warming potential and open cell spray foam needs a. Closed cell or open cell foam. Closed cell spray foam.

Instead i like to build a fully vented roof assembly that is insulated with closed cell spray foam. The amount of closed cell spray foam or rigid insulation is somewhere between 20 to 50 of the r value of the overall cavity insulation depending on your climate zone. I plan to use the closed cell spray foam insulation on 3 4 inch sheathing. If you want to use spray foam here s my advice.

The evaluation service report esr for spray foam insulation products provides a valuable resource based on a third party review of testing information useful for utilizing these products successfully and according to code. There are fewer reports of problems with closed cell spray foam than with open cell spray foam. It rots roofs people have told me. Both low density open cell and medium density closed cell spray foam can be used in an unvented attic to provide the needed thermal resistance and airtightness.

The main drawback is high cost. Unless you live in climate zones 2b or 3b desert area s in texas new mexico arizona california the codes and common sense will point you to closed cell foam. It doesn t fill the cavity though so spot checks may be required to check you don t get shorted. More common of the two types of spray foam closed cell is mostly used for commercial roofing.

Closed cell foam has a higher r value per inch and installers generally spray 2 in walls and 3 in roof lines to meet the energy code requirements of r 13 and r 19 respectively.