Just a little added info on open cell and closed cell.
Numerous homes have been done with Icynene, Sealection 500, Biobased.
NCFI and Corbond. Spray foam is a chemical.
The difference between different brands is the recipe used in the chemistry. Icynene, Sealection 500 and Biobased are referred to as open cell foams. (although Demilec, Biobased and NCFI manufacture closed cell foams as well). Open cell foams typically weigh between .4 to .6 lbs per ft3 fully cured.
As opposed to closed cell foam which weighs 1.6 to 2.2+ lbs ft 3.
Open cell foams use water as a blowing agent where as closed cell uses a zero depletion blowing agent, typically Enovate manufactured by Honeywell.
Open cell foams have an R rating of 3.5 to 4 per inch. Closed cell foams have R’s ranging from 6 to 7.3 per inch.
This means open cell foams usually have to be 2 x the depth to achieve comparable R value of closed cell. Most of the time, this requires open cell to completely fill a 2x4 or 2x6 wall cavity to yield R values comparable to 2 to 3 inches of close cell.
The excess foam then must be shaved off to accommodate drywall. Such activity adds labor cost and waste.
Neither product is particularly great at absorbing sound.
Moisture can move rather easily through open cell foam via diffusion as its permenace is 6 to 10.
Whereas closed cell foam has a perm rating of less than 1.
Since open cell foam has a high open cell content (90%+/-), liquid water can enter the foam rather easily.
Conversly, closed cell foam has greater than 90% closed cell content and resists liquid water quite nicely. Closed cell is used as a weather or rain barrier.
As to which product (closed cell-open cell) is the best choice for your home – the answer is ------It depends. A huge factor is your climate. Can you be assured of indoor humidity levels between 35% to 50%? Is there duct work in the attic. (if not, there is absolutely no good reason to spray a roof deck with foam.)What type of exterior sheathing will you be using? Do you possess the skills to air seal the envelope?
On the practical side, Testing of identical homes side by side with a blower door, it was found, little to no difference in the air leakage rates between an Icynene insulated home and a home with cellulose in the walls and ceilings that was properly air sealed.
Open cell foams are also much more caustic than closed cell,(Corbond)during the installation process.
One of the biggest reasons, I believe there has been an increase in foams being used in homes is that a builder cannot go to the yellow pages and find a contractor that specializes in air sealing.
Since most builders now a days don’t hammer nails and rarely get involved in the actual construction of a home, this is a huge headache for them. Foams allow the builder to delegate the air sealing task to the foam installer.
As far as the differences between Icynene and Sealection 500, it has been my experience that Icynene has little trouble stretching the truth, making unsupported claims about their product while being critical of their competition.
I have not found that to be the case with Demilec, Corbond or Biobased. They seem to stick to the features and benefits of their product which tends to give them more credibility in my book.
According to the ESR’s, it appears that one requires a vapor barrier and the other not.
It also talks about a thermal protection board on both products.
In certain conditions for the Icynene.