The problem was that the installer was doing his first spray foam job ever, and the thickness of the insulation varied from zero (visible roof deck) to about 9". Unfortunately, good average thickness doesn't cut it. The coverage needs to be uniform because a lot of heat will go through the under-insulated areas. (See my article on flat or lumpy insulation performance.)
how much is spray foam
Spray polyurethan foam does effectly prevent all six of these heat transfer methods from occurring. These should be the mechanisms by which you judge insulation, in addition to their R-Value. If you're uncertain about installing spray foam insulation, Energy Star has a map that recommends levels of insulation by R-value and cost-effectiveness in the United States.
This depends on the geographic location, insulation, and cost of electricity. Lawrence Berkeley National Laboratory (LBNL), Oak Ridge National Laboratory (ORNL), National Roofing Contractors Association (NRCA), and several roofing material manufacturers have computer programs that can estimate the savings. A growing number of energy consultants are available to provide environmental regulation compliance information.
where to get spray foam
Small imperfections in the building envelope (holes, cracks, gaps) not properly sealed will eventually lead to poor building performance or worse, moisture accumulation, allergen/pathogen growth, and very possibly structural failure. The solid nature and sealing capability of closed-cell spray foam, inhibits moisture-driven elements. Two inches of closed-cell spray polyurethane foam insulation will minimize air infiltration, exfiltration, convection, conduction and control solar driven moisture in the building envelope.
Repair and seal roof penetrations, tears, open seams, etc. using Elastek 103 Crack & Joint Sealant and reinforce with polyester roof fabric as necessary. In larger or deep ponding areas, apply Elastek 500 Puddle Plaster to fill in areas that hold water. Avoid using plastic roof cement. Serious ponding should be referred to a roofing contractor. Blisters in previous coatings may be opened but these areas must be allowed to dry-out completely. Blisters in the roofing ply should be left alone unless likely to break. Caulk and reinforce open seams, roof penetrations, cracks, and tears. These are potential leak points so work carefully and thoroughly. Use fabric to build flashings around roof edges or roof penetrations, and to reinforce various coating repairs. A polyester fabric is used because it will stretch with the coatings. (Fiberglas fabric is not recommended.) Fabric is normally cut to extend three inches beyond the repaired area in all directions. The coating is applied to the roof surface and the fabric is immediately pushed into the wet surface. An additional coat is applied over the fabric and the patch is allowed to dry. If your roof has stucco parapets, examine them for cracks along the sides and top. These areas often permit water to enter the wall and can cause blisters and wrinkles in the roof surface. Repair with Elastek 103 Crack & Joint Sealant. If you do not have parapets, examine the metal drip edge for a tight seal with the roof membrane. Use 4″ or 6″ roofing fabric covered under and over with Crack & Joint Sealant to seal cracks along drip edges, penetrations, and open seams.
Roof coatings are easy to install. Smaller roofs in good, serviceable condition can be a weekend do-it-yourself (DIY) project. Larger roofs with leaks and ponding water issues should be coated by a qualified professional. Additional roof coating products, such as foam or coatings designed for seams, may be required underneath the main coating layers. Supplement coating products are used to reinforce damaged or leak-prone problem areas. https://m.youtu.be/ggLAUsiuI_o