This was lengthy article so I only took out a small portion.
Paul Duffy, the vice president of engineering for Icynene, advises anyone considering the use of spray foam in an existing house to hire a home-performance specialist. “For a retrofit job, we recommend that you have a HERS rater involved, or a BPI-trained professional — someone who understands the house as a system,” said Duffy. “A spray foam contractor doehttp://epa.gov/dfe/spf_presentation_2009_epa_osha_niosh_cpsc.pdfsn’t necessarily have all of those understandings on the same level. … It goes beyond the skill set of insulators generally; it goes into the skill set of a building science professional.”
Point about closed and open cell foam insulation is the smell can be so strong if not using the proper application or company.:shock:
Good presentation info on SPF.