Insulation for Roofing Deck

LESLIE: Alright, now we’ve got Ron who needs some help with insulation. What can we do for you today?
 
RON: Well, I was – I’ve had radiant barrier type stuff – it’s called E-Barrier from Sherwin Williams – sprayed on my roof decking. And I have r38 insulation and I was just wondering if it would be cost-effective to add anymore insulation to the r38 factor I have already.
 
TOM: It sounds like you’ve got enough.
 
RON: OK.
 
TOM: So r38, you have, what about – well, let me think about this. You’ve got, what, about …
 
RON: Fifteen-and-a-half inches.
 
TOM: Fifteen?
 
RON: Yeah, 15 inches of …
 
TOM: Is it batt or is it blown-in?
 
RON: It’s blown-in.
 
TOM: Oh, it’s blown-in. Well …
 
RON: Fiberglass.
 
TOM: And typically you want 19 inches of batt or 22 inches of blown-in; so you probably, if you’ve got the room, could add a little bit more blown-in and still get some return on investment.
 
RON: OK. And one other question, though. How about foam insulation? How does that stack up to the other type; the blown-in?
 
TOM: Well, at this point, you’re already committed on the fiberglass blown-in, so I would not switch to a foam product. But if you were starting from scratch, it’s a good product.
 
RON: OK.
 
TOM: I’m talking about the expandable products like an isonene product; typically used more so in new construction than a remodeling application. But they’re good products, they do a good job and they also seal out drafts as well as insulate at the same time.
 
RON: Alrighty. Well, I appreciate your time.
 
TOM: You’re welcome, Ron. Thanks so much for calling us at 888-MONEY-PIT.