In general, cantilevered steel beams are a nightmare. If part of the steel beam is in contact with exterior temperatures, then it's best if the interior portion of the steel beam is covered on all sides with insulation. This is generally impossible (because the interior portion of the cantilevered beam generally supports a load, meaning that you can't wrap the steel beam in insulation on all sides).
I don't know if it's common or uncommon, but installing a layer of rigid foam above your roof sheathing in order to interrupt thermal bridging is always a good idea, and is preferable in all respects to a roof assembly without any rigid foam above the sheathing. If you decide to install rigid foam above the roof sheathing, you shouldn't use closed-cell spray foam under the sheathing; either use open-cell spray foam (which is vapor-permeable) or a fluffy insulation like cellulose, mineral wool, or fiberglass (any of which will allow the roof sheathing to dry to the interior).
Elastomeric coatings offer effective and affordable solutions for fixing roof leaks. The coatings can be used to repair any type of roof leak. The elastomeric roof coatings can be used throughout the year because they stretch and contract easily to adjust to winter and summer temperatures. It is usually made using polymeric products such as acrylic alongside white pigments like titanium dioxide. This helps create an opaque and reflexive final product. http://youtube.com/watch?feature=youtu.be&v=ggLAUsiuI_o
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).
This is in great contrast to my friend's experience. Her attic spaces were sprayed and the foam is actually pretty, and I was in her attic 6-7 days after it was sprayed and could hardly smell anything when I stuck my face up to the foam. And she did not have to clean up one speck of dust during or after the spraying. I got the name/number of the guy from her who managed her attic project, but between the time he did my house and the time he did her house, he was let go from the company who did her attic and hired by another company. He assured me everything would be the same, etc., etc., and I had no reason to believe anything had changed, but the sprayers who did my house later admitted they had never sprayed an attic before and I also found out that the foam used in my attic was from a different manufacturer. Neither my friend nor I had any idea this guy was with different company then, until the week after they filled my attic with off ratio foam, and my home with toxic vapors. https://m.youtube.com/v/ggLAUsiuI_o
Sealection® 500 has been Demilec's flagship product for more than 20 years, and has positioned Demilec as an industry-leading spray foam insulation manufacturer. As an environmentally-friendly product, it delivers superior performance, energy savings, and is an excellent return on investment for architects, builders, contractors, and homeowners, making it the ideal choice for insulation.
I've seen this only once, and it was with closed cell foam, but I've heard of it happening with open cell foam, too. I don't know the details, but I've heard it could result from a bad batch of chemicals, improper mixing, or too high a temperature. Whatever the cause, it's not a good thing. The photo below shows how the spray foam pulled away from the studs. A little bit of uninsulated area like that adds up to a lot of heat loss/gain when the whole house has that problem, as it did here.
Closed-cell spray insulation, a rigid medium-density material, can be used in exterior applications such as continuous insulation applications, as well as interior applications. This type of foam insulation has a higher R-value per inch making it also suitable for small areas that require the highest possible R-value to meet building code requirements. Closed-cell spray foam’s rigidity help reject bulk water making it a recognized flood-resistant material by FEMA.
Before you decide on spray foam or another method of insulation, it's important to understand the superiority of spray foam compared to traditional materials. When compared to fiberglass batts, spray foam offers nearly double the R-value per inch, achieves air-sealing and insulation in one step, won't be damaged by mold or moisture, and won't settle, compress, or otherwise be damaged to the point it needs replacement.
Where Can I Buy Closed Cell Spray Foam