I don't even want to ask this question but... several years ago we hired a local contractor to spray high density foam on the roof deck and walls of our unfinished 2nd floor. We realized that the job was done poorly and cut an access into the attic space to assess things. We realize now that they spray foamed directly to the chimney (no flashing). The chimney is currently used for a woodstove and DHW venting. The DHW will go away but wood stove will remain. My question is, how bad (unsafe) is this? I have found information on foam exposure to fire but have not been able to find anything about temperature ratings in general (i.e. what happens on prolonged exposure to high temperatures).
The process by which heat energy in the form of light (usually IR unless the substrate is hot enough to glow in the visible range) is emitted more strongly by warm surfaces and absorbed by other materials especially those of low IR reflectivity (think matte black finish). Radiant heat transfer does not require a medium. Foam insulation materials, such as spray foam insulation, are opaque to thermal radiation, like most solid materials.
The roof must be thoroughly cleaned, and allowed to dry thoroughly. This is a critical step to ensure a successful coating application. Be careful not to damage the lap seams. Care should be taken when pressure washing not to disturb the integrity of the underlying roof membrane particularly where there are adhered seams. Refer to the specific coating manufacturer you are using for their specific requirements for roof preparation.
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.) https://m.youtube.com/embed/ggLAUsiuI_o
I started using Gaco years ago primarily to solve ponding water Problem. It has work well, solved my problems with other roofing options and repairs as well as many other Flat roof issues. My only problems were experienced when I did not clean the surface well enough for good adhesion. Follow the Instructions. Great product and highly recommended. . http://www.youtube.com/watch?v=ggLAUsiuI_o
One of the key differentiators between traditional insulation materials and spray foam insulation is the latter’s ability to insulate and air seal. Foam insulation provides an air barrier to wherever it is applied to help mitigate air leakage from the building. Air sealing the building envelope with sprayed-in foam insulation also helps address moisture ingress to reduce the risk of mold and mildew growth as well as the formation of ice dams in colder climate zones during the winter months. When you compare foam insulation with traditional fiberglass insulation and cellulose insulation, sprayed insulation minimizes air infiltration, it assists in limiting moisture vapor from entering and escaping the home, which in turn reduces the load on heating and cooling systems. Below is a video that compares fiberglass, cellulose and open-cell spray foam in terms of insulating and air sealing value.
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Our roof coating sprayers are designed to provide the coverage, flow rate, and pressure needed for all your applications. Durable Graco roof coating sprayers are equipped with valuable features that make them extremely versatile. High-quality parts plus gas, electric, air driven, and hydraulic options means we’ll have a sprayer that fits your needs. Our systems are designed to be used with elastomeric roof coatings, silicone roof coatings, acrylic roof coatings, asphalts, rubber roof coatings, and other materials.
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Though foam insulation has a higher upfront cost than fiberglass or cellulose, it recoups this expenditure in a relatively short period of time. Additionally, the insulation’s permanence means that it will continue to generate savings over the life of your structure. The durability of this insulation means that you can rest easy in the knowledge that at least one component of your structure will stand the test of time. https://youtube.com/v/ggLAUsiuI_o