Closed-cell (aka two-pound foam) is denser than open-cell at about 2 pounds per cubic foot. Its R-Value is between 6-6.5 per inch. As a result, this kind of foam is much more expensive than its counterpart. The reason closed-cell doesn't need a vapor retarder is because it already has one. It's permeance is 0.8 perm, which means it can handle cold climates without the use of an additional board or drywall. Closed-cell uses hydroflurocarbons (HFCs) as part of its makeup. However, this material has been known to have a high global warming effect. If you want a green insulation solution, this is not the material to use. A way to avoid this and still use closed-cell is by installing it alongside fiberglass batts. https://youtube.com/v/ggLAUsiuI_o?version=3
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).
Due to its relatively large cell structure, low-density foam stays somewhat soft and flexible after curing. This increases the likelihood of its continuing to provide high insulation value even as the building settles and shifts over time. Low-density SPF provides heat insulation and seals airflow through cracks, joints and seams by filling the cavities. In addition, this foam can help absorb sound thanks to its soft texture and open-cell structure.
Although spray foam insulation has been in use since the 1940s, primarily for aircraft, for the past 30 years, continual product innovation has seen the increased adoption of spray foam insulation in residential and commercial construction. The rapid growth of sprayed foam insulation in building construction, thanks in part to its immediate and long-term benefits, has allowed the insulation material to sit confidently alongside traditional insulation types in providing thermal comfort for building occupants. https://m.youtube.com/v/ggLAUsiuI_o
Spray Foam Basement Walls Cost
Most closed-cell spray foam is now formed using hydrofluorocarbon (HFC) blowing agents that have high global warming potential, partially or completely offsetting the climate benefits of the energy savings they can offer. In the United States, HFCs are scheduled to be phased out by January, 2021. A few spray foam suppliers have started supplying spray foam blown with hydrofluoroolefin (HFO) blowing agents without this problem as of early 2017. http://youtube.com/e/ggLAUsiuI_o
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.