One issue with flash-and-batt is that it’s absolutely not a DIY project: the equipment is specialized and expensive, and you need to take real precautions to protect yourself from the unreacted chemicals. But you might be able to get a local spray foam contractor to do it for a few hundred dollars if you ask nicely and let them come by on their schedule when they’re already doing a job nearby.
Frame first — you want the foam to stick to the exterior shell and to the framing members that are up against the exterior. Protect anything you don’t want foamed — the fresh foam sticks to everything and foam in your electrical boxes is no fun.
(The unreacted chemicals are not persistent — they’re too reactive to stick around.)
Frame first — you want the foam to stick to the exterior shell and to the framing members that are up against the exterior. Protect anything you don’t want foamed — the fresh foam sticks to everything and foam in your electrical boxes is no fun.
(The unreacted chemicals are not persistent — they’re too reactive to stick around.)