I am an Architect in Toronto. I am designing a new roof addition to a row house building. Because of existing conditions and the shape of the new roof. It may be easiest to use closed cell spray foam within the areas of the joists. My question is when spray foam is used in this situation do I need to worry about how the joist members may be thermal bridges? It is not common to provide a little bit of rigid insulation to protect the joist members? The additional layer of outboard insulation will require an extra layer of plywood above the insulation which will add to cost.
R-value is the term given to thermal resistance to heat flow. The higher the R-value of an insulation product, the more effective the insulation properties. Spray polyurethane foam comes in a range of densities and cel structure. Low density foams are referred to as Open Cel SPF while higher density foams are referred to as Closed Cel foam. 1.8-2 pound polyurethane foam has the highest R-value of readily available spray foam insulation used in homes and buildings.[4]
Good article, but it seems like you can chalk up almost all of those problems to the experience level of whomever is spraying the foam. Spray foam isn't an inherently bad product, but it's pretty easy to botch if the hired company is inexperienced. Fiberglass may be foolproof to install, but then again it has a terrible R-Value compared to a good spray foam. People just need to get referrals and do their homework whenever they research a spray foam contractor.

Spray foam insulation, when properly installed is both an air barrier and when closed cell foam is used at the proper depth a vapor barrier!  Before hiring any contractor you should establish the brand of foam being used and verify that with the named manufacture.  Please ask for ESR reports and MSDS sheets on any foam being installed in your home. A couple areas where you might consider spray foam insulation include:
Spray foam insulation or spray polyurethane foam (SPF) is an alternative to traditional building insulation such as fiberglass. A two-component mixture composed of isocyanate and polyol resin comes together at the tip of a gun, and forms an expanding foam that is sprayed onto roof tiles, concrete slabs, into wall cavities, or through holes drilled in into a cavity of a finished wall. http://youtube.com/watch?v=ggLAUsiuI_o
These coatings are emulsified asphalt and consist of asphalt particles dispersed in water; they utilize clay as the emulsifying component. These coatings also contain many types of organic and/or inorganic fibers and fillers to provide extra strength to the coating. These coatings are available in black, brown, or as a reflective coating when titanium dioxide or aluminum pigments are added. https://www.youtube.com/watch?v=ggLAUsiuI_o&hc_location=ufi
They’re the more expensive option than the first one we have discussed above, but they also offer top benefits for the RV owners who want to repair or maintain their RV roof and protect it from UV rays and harsh weather elements. Based on many reviews, these types can offer more durability than the silicone and acrylic types. They can also offer an excellent impact resistance from twigs, leaves and other outer elements.

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.

The problem you saw with the closed cell foam pulling away like that is due to the heat of the foam was to hot. It was actually curing out and making foam before it could adhere to the wood. The installer wasn't reading his foam correctly. He should of stopped and turned down the heat on his hose temp. Also installers have to be aware that as the sun rises and the temp in attics rises the subtrates get hotter as well. This will cause the installer to adjust his heat when installing the foam as the temp changes thru out the day.  


One of the best ways to achieve it is to use the Heng’s rubber coating that can protect it from the elements, including sleet, wind, rain, and snow and UV rays. The product also does well in keeping our roof protected from dirt, leaves and twigs. With such protection received, our roof won’t degrade and we prevent ruining our recreational vehicle investment. https://m.youtube.com/watch?v=ggLAUsiuI_o&feature=youtube_gdata
EPDM coatings has been featured in Article Insider, as well as Roofers Exchange, Building Service Management and recently won Metal Roofing Magazines product of the year. Since it’s the only liquid form of EPDM rubber in the world, made right here in the U.S.A. there are many distinct advantages to the product vs other roof coatings. It waterproof as soon as it is applied, will take standing water indefinitely yes that means 365 days a year of continued ponding water. The product comes with a pre-measured bottle of catalyst that is added to the container. Once the material is mixed you have a 4 hour time period to apply it before it starts the initial set up process. The product requires daytime temperatures of at least 55° to cure. Temperatures can fall below 55° at and once they rise again above the 55 degree mark it will continue to cure. Any non-opened can be stored up to one year without it going bad. Roof leak repairs are an unwelcome reality to every owner of a residential or commercial building, mobile home or recreational vehicle. Roof leak repairs can include almost anything including replacing damaged shingles, mending holes, fixing roof leaks, or repairing dents with roof coatings.

Spray Foam Professionals


The problem you saw with the closed cell foam pulling away like that is due to the heat of the foam was to hot. It was actually curing out and making foam before it could adhere to the wood. The installer wasn't reading his foam correctly. He should of stopped and turned down the heat on his hose temp. Also installers have to be aware that as the sun rises and the temp in attics rises the subtrates get hotter as well. This will cause the installer to adjust his heat when installing the foam as the temp changes thru out the day.  
We service the entire Central Texas Area including Waco, Abilene, Fort Worth, as well as Granbury, Aledo, Weatherford, Eastland, Hico, Hamilton, Brownwood, Comanche, Glen Rose, Meridian, Cleburne, Mineral Wells, Graham, Breckenridge, Decatur, Eastland, Ranger, Gorman. We have done work as far away as Colorado, so don't hesitate to call if you're outside this immediate area.

How Much Is Spray Foam Insulation Cost


Another thing we love about the Liquid Roof is its ability of not being damaged by freezing and other extreme temperatures. You will also appreciate its ability of staying flexible for a longer period of time. Did you know that it could also contract and expand as you roof moves? That is one of the things to look for when shopping around for this kind of product we found in the Liquid Roof.


The Canadian National Building Code references the CAN/ULC S705.2 National Application Standard which must be followed during all installations of 2lb medium density closed cell polyurethane foam. Every installer of CAN/ULC-S705.1 compliant medium density, spray applied foam must be licensed in order to spray foam and hold valid photo ID issued by their Quality Assurance Program (QAP) provider showing their license is in good standing.
Today, each of the 50 states follows a different set of building codes making navigating these codes confusing, particularly for architects or builders that have projects in multiple states. In some cases, the building code changes significantly between the state and certain cities or counties within the state. For example, at the time of writing Arizona had adopted the 2015 IRC Building Code, however, Phoenix was on the 2012 IRC, IBC and IECC code. With the majority of states either on the 2009, 2012 or 2015 code, below are some high-level points to consider and about how spray foam insulation contributes.
As this example illustrates, it's important to seal the envelope completely. One of spray foam's biggest selling points is its air-sealing ability, but it can't seal places where it's not sprayed. One of the nice things about using spray foam in new construction is that you can do a Blower Door test before the drywall goes in. Even better, you can test for leaks with a fog machine. http://youtube.com/e/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).

Tip Top Roofing Inc. has attained high standards for roofing restoration with 26 years of experience. We are a fully licensed contractor ( 826997) for your security. Tip Top Roofing Inc. uses top-quality products and we strive to be the experts in the business. Our experienced talent and efforts are always continual in our services. We provide information on roofing products and solutions to better our customers requirements.  
These coatings are emulsified asphalt and consist of asphalt particles dispersed in water; they utilize clay as the emulsifying component. These coatings also contain many types of organic and/or inorganic fibers and fillers to provide extra strength to the coating. These coatings are available in black, brown, or as a reflective coating when titanium dioxide or aluminum pigments are added.

How Much Does Spray Foam Weigh

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