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January 31, 2008
Cellulose Roof Insulation
A note that might be of interest to people thinking of having insulation blown into their roof--30 years ago I had cellulose insulation blown into my roof. That stuff is made from re-cycled newspaper with a chemical fire proofing.
I was always concerned that the fire proofing might wear out over time. This morning I have an electrician working in my top floor bathroom. I took a handful of the cellulose that came out and tried to light it on fire. I was very happy to see that it's STILL fire proof--it smoldered for a moment and extinguished itself, just as it did when I tested it back in the 70s. Of course my "test" isn't conclusive and the cellulose insulation being produced now might differ from what was available back in the day, so, although I'm reassured, YRMV
Comments
I once saw a house that burned to the ground. You know, right there in the middle of the ashes was the cellulose. Convinced me to get it.
Posted by: guest at January 31, 2008 5:17 PM
Do you have to get all the electrical work etc. done before you blow in insulation or is it possible to open the ceiling later if necessary?
Posted by: ohiise at January 31, 2008 6:37 PM
Probably better to have electrical work done first, but I just had some minor electrical work done 30 years after having the cellulose insulation blown in and, since the electricicians only made two small holes, only a few handfuls of cellulose fell out.
Posted by: Bob Marvin at February 1, 2008 5:14 PM
What if your house has been completed and would like to get this insulation on the side walls of the house because knocked down a few plaster walls and redid with sheetrock. Would it be to late? How much does it cost and how big does the hole have to be for installation? Thanks
Posted by: guest at February 4, 2008 5:52 PM
I've done a lot of asking around about cellulose and concluded it is the best of the best in terms of green insulation, unless of course you can find salvaged poly ISO board which is better but not easy to find.
I have also talked to the engineers at one of the top cellulose manufacturers about installation. Here is the scoop:
You want to dense pack it so that it does not sag over the years. It is fluffy so it compacts with time. Unless of course you dense pack it. The correct blower will dense pack it to 3.5 pounds per foot, which to give you an idea is like putting a 3.5 pound metal plate on top of a cubic foot of it. That's how much it would pack down.
You can get an installer to do this because they have put up the hefty money to buy a blower.
OR if you are a DYI type you can rent the crappy Home Depot blower that is only good for loose fill blowing AND THEN PACK THE CELLULOSE DOWN WITH A STICK.
Sounds very unscientific I know but I confirmed with the engineers who make the stuff and they said it is a great DYI solution.
So you make some holes in the wall and just pack the stuff in. That simple.
Of course you need to check the walls with a stud finder to make sure you get every section both horizontally and vertically. And you don't want to ram your stick (a 2x4 is good) into an electric wire or pipe.
FYI they still use Borate as the chemical in the cellulose to make it fireproof and anti vermin. Borate is water soluble so as long as the insulation doesn't get wet the stuff will stay good for longer than we will. That's why mice and termites don't nest in it or eat it.
Posted by: gennaro at December 29, 2008 8:20 PM
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