Cellulose insulation
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| Posted in Energy Efficiency and Durability on
I am building an efficient and “greenish” home on Southern Vancouver Island, which has the same climate as Seattle.
I am at the stage where I need to make final decisions on insulation. Local contractors are advising against dense pack cellulose in the 10″ double stud walls. Their Reasons are: Settlement over time, dust, mould, insects, rodents, labour cost of installation.
Are these worries unfounded? Obviously I want something “green” in my walls, but only if I can expect at least 50 years of service from it.
Any comment or experience would be greatly appreciated.
Thank you
David Slade Cobble Hill BC
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Replies
David,
What are they proposing be used in the wall?
One of the issues that can come into play is having access to a good installer. It's been pointed out that the Pacific Northwest "appears" to rely on blown in fiberglass more than cellulose. Some fibre glass products when used with netting are easier to install and therefore more reliable because they are so fine that they instal at lower densities but so stringy that they resist sagging due to less weight and more "webbing".
However, there are plenty of builders that use cellulose at higher densities (3 to 4 ft3/lb). The high density yields a better R value and resists sagging. Many feel that an added plus is the cellulose's ability to safely hold and distrubute moisture throughout the thick wall assembly.
You've got a 10" double stud wall. It's your choice what goes in it, but you've already made a good choice in building a high R wall. Life is good.
I agree that installer comfort/experience should be the deciding factor. Double wall cellulose installation requires some skill and you don't want them acquiring it on your house. Here in Maine we're lucky to have an increasing number of talented installers, and cellulose in double stud walls is our preferred wall system.
As far as any generic concerns about the other issues, I don't think there's much merit. I'd much rather have cellulose in my air than fiberglass.
I can understand a contractor not feeling qualified to dense pack cellulose in a 10-inch wall. That takes skill and experience. When they bring dust, mold, insects, and rodents into the mix I begin to suspect the contractor(s) either know little about cellulose insulation or, if they do know, are just not speaking candidly. Here are the facts. At 3.5 pcf you can't make cellulose settle in an 8-foot cavity, even a 10-inch thick one. Mold doesn't like cellulose insulation very much. All the widely reported cases of serious mold contamination of insulation have involved fiber glass. Ditto for insects. I know of no definitive data on rodents and cellulose insulation, but on two occasions I have had to use professional pest control operators to deal with rodents in fiber glass.
David,
Q. "Their reasons are: Settlement over time, dust, mold, insects, rodents, labor cost of installation. Are these worries unfounded?"
A. Yes, these worries are unfounded. What's apparently going on here is simple regional prejudice. There's something about the Pacific Northwest that doesn't love cellulose. Once these regional prejudices become embedded in the local folklore, they are hard to change.
The problem, as the other responders have noted, is that your area apparently doesn't have any skilled installers familiar with cellulose. If the skilled installers are lacking, you have to go with what is available.
We just experienced the same attitude towards cellulose in the midwest. We had planned double wall construction with dense packed cellulose for the cavity and 2 inch rigid insulation on the exterior. The insulator said he won't do cellulose because of mold issues. Of course blown in fiberglass is okay with him. He's going to forward us his preferred wall construction and I am open to other ideas. We will keep looking for the right tradesperson. Does anyone have any ideas how to find one? We are building north of Milwaukee, Wisconsin. Perhaps the strategy is to find the manufacturer of the material and then look for qualified installers from their website. Comments?
Christine,
I don't know where you are in the Midwest, but there are many cellulose manufacturers headquartered in the Midwest. Perhaps you can contact a manufacturer near you and ask about local contractors.
Applegate Insulation
1000 Highview Drive
Webberville, MI 48892
800-627-7536
517-521-3545
http://www.applegateinsulation.com
Regal Industries, Inc.
9564 E. County Rd 600 S 47229
Crothersville, Indiana 47229
812-793-2214
http://www.regalind.com
Central Fiber – Kansas (Head Office)
4814 Fiber Lane
Wellsville, Kansas 66092
785.883.4600
Toll Free: 800.654.6117
Fax: 785.883.4429
http://www.centralfiber.com
Nu-Wool Company, Inc.
2472 Port Sheldon Rd. 49428
Jenison, MI 49428
800-748-0128
http://www.nuwool.com
Facing a similar lack of contractor support for dense pack cellulose, I've switched to mineral wool bats (Roxul). I have gone to a 10 1/2" cavity & plan to use r30 bats in the exterior wall and strips of r15 between framing members both horizontal and vertically then r 15 in the inner stud cavity. for r45 in the 10.5" cavity I would need a 12" cavity for about the same r with cellulose. The material cost is within a percent or 2 of cellulose.
Christine
Here in Central Wisconsin our local Insulation contractor with a lot of Cellulose experience is Home Insulation Wausau WI. 715-359-6505, they travel. I suspect that there are some installers in the SE WI. area too but don't have any names for you.