Adding Attic Insulation and Mixing Insulation Types
LESLIE: We’re going to talk to Ted in Texas about attic insulation. How can we help you?
TED: Well, I had a question. I was going to put some insulation in my attic and I had heard about a spray type material that you could have a contractor do and they could – you know, it would, I guess, stick to the rafters and all that and I was just wanting to know if that stuff is – you know, you hear a lot of hype about it but I don’t want to pay for something that’s really not going to do what I want it to do. I live in Texas and it’s – you know, it gets really hot. So I’m wanting to know what the best way to, you know, insulate my house; especially when we’re, you know, talking 105-degree days.
TOM: Well, when you have an existing home and you already have attic insulation in there, for you to use a spray insulation would require you to remove all of that and I think that you’re probably going to be better off and just as cost-effective to add additional insulation to the existing insulation that you have rather than completely remove and replace. When it’s brand new, the spray foam insulations work very, very well because they seal at the same time. But for an existing home, for a retrofit situation, I think that my recommendation, Ted, would be for you to add additional insulation. And you want to have probably a good 12 to 15 inches in the attic when you’re done, of built-up insulation.
TED: OK, what is the – I mean what’s the primary reason for having to remove the other insulation?
TOM: Because this insulation is designed to stick to the drywall surface and in between the rafters and then expand and it can’t be mixed with fiberglass insulation. You say spray foam. You don’t mean blown-in, do you?
TED: Well, it’s …
TOM: Because blown-in insulation, which is fiberglass, generally can go on top of the existing insulation. The negative thing about blown-in insulation is that it makes the attic absolutely impassable when you’re done and you need a lot more thickness of it because it has more air inside of it than you would if you used fiberglass bats.
TED: Well, I saw one of the – I saw another home that was being built and it seemed like the insulation, when they sprayed it on up underneath the decking it only looked like it expanded out about a half on an inch. And so I thought, well, maybe that would be something that – you know, and I can’t remember what they called the product but I did see it on TV and I was just …
TOM: Well, there’s – one of the most popular ones is a product called isonene, which is a very, very good product. But again, it’s something that I would look at if I was doing a new construction. I probably wouldn’t use it for retrofit.
TED: OK. OK. Alright, well that’s …
TOM: How much insulation do you have right now, Ted?
TED: In some areas it’s probably maybe eight to ten inches.
TOM: Yeah, I would just – I would add another six inches of unfaced fiberglass bats on top of that.
TOM: That would be very cost effective, easy to do and it’ll give you good return on investment.
TED: Well I’ve got really high ceilings and, of course, my air conditioner is up in the ceiling and my house is only like seven years old and I have like 14-foot ceilings in some parts. So I was just wanting to get the most bang for my buck because here in Texas it’s …
TOM: I know.
TED: … you know; it’s not uncommon to have a …
TOM: That’s what I said. Make sure you have enough attic insulation and make sure you have plenty of attic ventilation …
TOM: … and that will be a good investment for you.
TED: OK, great. I appreciate it.
TOM: You’re welcome, Ted. Thanks so much for calling us at 888-MONEY-PIT.