Hi,

Our original plan was spray foam insulation for the new additions, garage, sunroom, master bedroom over garage. I talked to our builder a couple days ago and expressed my concern about a possible cold master bedroom because it is above the garage. Today my builder came to me and said the insulation guy offered cellulose blow for the garage ceiling, which could increase the R value from R30 (spray foam) to R38 for the same cost. I am confused because I thought spray foam had a better performance than cellulose and was much more expensive. How can cellulose increase the value to R38? Is that a good idea to use cellulose in garage? I know it absorbs moisture so potentially may have mold problem. Does it make sense for the same cost, using cellulose instead of spray foam?

Thanks for any advice.