Closed cell vrs open cell
We are building a house in CT and I think closed cell spray insulation makes a lot of sense. My builder would rather do open cell because the house can breath a bit??
Well your builder might need to learn some more about building science as that argument doesn't hold water especially as many manufacturers love touting there products "air-sealing" abilities. With that using closed cell foam has plenty of benefits which it sounds like you realize, but one of the cons can be the price. The biggest item to remember is that closed cell should be used anywhere where moisture can be an issue - roof decks, basements, rim joist areas, behind tubs & showers, etc... Beyond that open cell is perfectly acceptable but there is no reason why you couldn't use closed cell throughout which I have done plenty of times. As for "breathing" - well the truth is houses don't but people & pets do so you need to install some sort of ventilation system per the newer codes & common sense. For more?: http://blog.sls-construction.com/2013/building-science-house-needs-to-breathe http://blog.sls-construction.com/2013/bs4d-ventilation-strategies