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Insulation nation

Posted by Rona Fischman  November 13, 2009 02:17 PM

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What is that stuff in the attic floor bays?

If you are lucky enough to have insulation in the floor bays of your attic, what is it made of?
If you are really lucky, you could have cellulose – stuff made of old newspapers. Cellulose insulation looks like dirty cottony paper-pulp. You are also lucky if you have fiberglass (that pink cotton-candy-looking stuff.) These, fortunately, are the most likely things you will see in your attic floor, besides dust.

You might find one of the older insulating materials, UFFI. If you see it in an attic floor, it looks like gray Styrofoam. UFFI (Urea formaldehyde foam insulation ) does a great job of insulating. But, when it was put in houses in the 1970s, it was found to out-gas enough formaldehyde to make people sick. It was outlawed in the 1980s. That was long-enough ago that the offending gas has dissipated. So, if you had UFFI in your house in 1985, you were pretty unhappy; now, it is a good thing.

Also in the old-insulation-that-does-you-harm category is vermiculite. It is rock that has asbestos in it. The web information on this varies from big bright alarm bells to just-never-touch-it-and-you’ll-be-fine.

Then there is the old stuff, usually wrapped in brown paper. Inspectors don’t think it is toxic, but they also don’t think it insulates all that much. I frequently see newspaper and cardboard (doesn’t do a thing except collect dust.) Last week, I saw packing peanuts (maybe they were just spilled from a bag they were being stored in – I hope so!) Also, I see layers of what looks like aluminum foil without anything else; I think those are left over from old fiberglass that was removed.

Today, I heard about a new foam, to be used on the attic ceiling, not the floor. It is called Icynene. It sounds like serious insulation. I am skeptical about new building materials, so I’d love to hear from anyone who is using this. Also, applying foam to the ceiling goes against everything I have been taught by all the home inspectors about taking care of the roof. The prevailing wisdom is to insulate the floor of an empty attic, and let the roof breathe.

Just last week, I wrote about the perils of over-insulation without ventilation. Will this style of insulation make that worse?

The salesperson said that is "the new way"... But is it the better way?
What’s in your attic?

This blog is not written or edited by or the Boston Globe.
The author is solely responsible for the content.

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5 comments so far...
  1. Hi Rona,

    Steve from HouseMaster here. I just completed my home renovation and I used the Icynene expandable foam insulation in the entire house. It works great and they even sprayed the attic ceiling as well. I am very happy with the product, and as an inspector, I believe that we will be seeing it more often.
    It creates an envelope that works well in combating heat loss in the winter and heat gain in the summer. You could actually go into the attic in the summer and not break a sweat.

    Take care.

    Posted by Steve November 13, 09 03:41 PM
  1. Hi Rona,
    Highly recommend taking NAR's GREEN certification where you will learn all about foam insulation products. Your refrigerator has it, your hot top, spa, indirect heated how water tanks... the list goes on. The advantages are that it seals cracks, provides a moisture barrier, prevents drafts from within the walls, and a very high level R value. Spray in foam is expensive and often used in combination with glass. The awesome thing about foam is that there is a SR (slow rise) product that can be "pored" into existing walls between the studs. I have used a product from Tiger Foam (a DIY) to add insulation to the outer walls of my own condo, a typical brick building in the South End. With the use of an IR temperature gauge, I have already determined that the product is highly effective.

    Posted by jbf November 14, 09 12:51 AM
  1. Rona - I don't know where you get your information about building conditions or components but, it is usually inaccurate .It seems to come from home inspectors.You don't seem to understand that most home inspectors are not experts in anything. I would suggest that you upgrade your information sources. There are real experts out there.
    First, UFFI is is not now a good thing. UFFI is a fire hazard, and can out gas if it gets wet.
    Second, asbestos in vermiculite is rare in MA . The asbestos contaminated vermiculite came from Libby , Montana ,and very little of it came to MA . Most of the vermiculite in MA came from local mines .I have tested numerous samples of vermiculite and have only found asbestos in .04% of the samples.
    Third - Icynene has been around for over ten years and is hardly new.This product and others have been installed in rafter bays without venting for years and is code approved .
    Fourth - Every other observation you have on insulation is basically technically wrong.
    If you want to learn about building components consult an expert , Not a home inspector.

    Posted by REmaven November 14, 09 08:23 AM
  1. If you have vermiculite, you can gently scoop a half cup full into a plastic bag and send it to a lab for testing. They will be able to tell if it contains asbestos. I read that around half of vermiculite contains it, and half does not. It depends on which mine it came from.
    We tested ours when we bought our 1953 house, and it didn't contain any. If it does, you will need professionals to remove it if you want to do construction... or just leave it alone and don't mess around in your attic.

    Posted by Charlie November 14, 09 09:34 AM
  1. Icynene is great. Wouldn't call it new so much, I've used it for years.

    attics only need to be vented if they are vented attics (which traditionally they were). Its possible to design an attic which requires no venting (usually using spray foam, which btw comes in lots of flavors, separating into low density and high density). A properly designed non vented attic is arguably superior.

    I have to agree with REMaven, I find most home inspectors to know very little about what they are talking about. Granted they know more than most home buyers and real estate agents, but that's setting the bar pretty low. Unacceptably low for me.

    Posted by charles November 16, 09 01:11 PM
About boston real estate now
Scott Van Voorhis is a freelance writer who specializes in real estate and business issues.

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