We used it on our addition up stairs and some of the folks around here have it in there walls. The problem is it settles as time goes by, most are complaining that the walls are cold from the window sills up. Some people here had it blown in from outside and I canít say it looks so great having all those caps on the siding. As to my upper crawl space I have had to add more to it over the last two years. Not really cost affective in the end and not a good R value.