Hello all. My wife and I purchased a new home and unfortunately have had to almost gut the whole thing so our budget is extremely tight.
We live in NY and I'm in the process of reinsulating the whole house. The house is 2x4 construction for the walls and 2x6 in the attic (upstairs ceiling) and in the cathedral ceilings as well.
We can't afford spray foam so we purchased R15 for the walls and R19 for the attic. In the attic I need to put down some plywood for storage down the middle, so anywhere we don't have a floor I will add some R30 going across the R19 (won't be too much).
Here are our questions:
1. When installing the R15 in the walls, I've been told to use spray foam (Great Stuff) up and down the cavity where the 2x4 meets the sheating so it seals each cavity, as well as behind each electrical box. Does this make sense? Is it necessary? Will it help?
2. For the cathedral ceiling we were going to put a 1.5" baffle under the roof sheathing, then R15. We plan on installing recessed lights so i want to create a cavity for the heat to move. I've received other responses here that say to stuff with R30 and add foam board, but I thought compressing R30 from 9.25" to 5.25" would be lossing Rvalue and usless?
3. A neighbor recently reinsulated his daughter's room with R13 and then some 3/8" foam board (the fan type) before putting up sheetrock. Do you think this adds anything and worth the trouble?
Thanks in advance.