Tips for Adding Attic Insulation
LESLIE: Roger in Tennessee, welcome to The Money Pit. How can we help?
ROGER: Hi. Yes, I’ve got a small home. I’ve got an attic full of cellulose insulation. Well, [actually full] (ph). It’s only got eight inches so I know it needs more cellulose put up there. But my heat pump duct work goes through the attic and has the ceiling vents coming out in the rooms.
ROGER: My question was: one – if I want to do it myself, which I need to do it myself, where would I get the cellulose or if that’s what I’m going to put up there, what other kind of insulation could I do it – buy for do it yourself; and should I cover the duct work itself?
TOM: Well, you might find that the easiest insulation for you to work with is an unfaced fiberglass bat, you know. Because you can hold these and they’re in six or eight-foot lengths and they’re easy to sort of position. To put in a blown-in product you really blown-in equipment.
In terms of whether you can cover the ducts, absolutely. There’s no reason you can’t cover the ducts and, in fact, it would make it more efficient if anything.
ROGER: Think I should cover the ducts while I’m doing that other …
TOM: Well, you know, if they’re in the way, you can cover them or you can work around them. There’s no reason not to cover them. There’s no downside to this. And if you put the unfaced fiberglass bats in, Roger, make sure you put them perpendicular to the ceiling joists. So you put it across. So if the …
TOM: If the cellulose has settled down flat with the ceiling joist, perfect. Put the bats in 90 degrees opposed to the joist and you’ll get a really good insulation blanket.
LESLIE: If the cellulose is a little bit below the joist, do you want to fill in the rest or not?
TOM: You know, in a perfect world I’d say yeah. But I probably wouldn’t. I’d just put the insulation on top of it.
ROGER: Now, these bats, can I buy that at just the local …
TOM: Anywhere. Any home center. Yep. They come in 16 inches wide and 24 inches wide. And just make sure when you put them in, don’t go too close to the eave so you block your ventilation. Just make sure your vents at the overhang of the roof and, of course, at the ridge are free and open and clear.
ROGER: OK. We had an electrician up there doing some electrical work and he – I’ve got to get hold of him – but he seemed to say that some of the cellulose had settled in the wall. He looked down in the walls because it was open to the wall. He could look down in there and the cellulose had apparently settled in the walls itself, too.
TOM: Yeah well, that’s not unusual with cellulose. There’s almost always some settlement to it. But if you want to do it yourself, it’s a little bit of a hard material to handle. If you want to have an insulation contractor come in …
LESLIE: Well especially because it has to be pressurized so perfectly so it doesn’t push the wall.
TOM: (overlapping voices) Well yeah, if it’s done right. Sure. Exactly. But listen, most of your heat loss in your house is going to be through the ceiling. So even though you lost a bit in the walls, if you’re looking for a practical, inexpensive solution that you can do yourself, get unfaced fiberglass bats. Install them perpendicular to the ceiling joist and you will definitely see an energy savings next winter.
ROGER: Thank you very much.
TOM: Roger, thanks so much for calling us at 888-MONEY-PIT. 888-666-3974.