10-25-2010 03:35 PM
I had a blower door test done on my home and the report came back giving me some "low hanging fruit" ways to eliminate 80% of where the heat was escaping. The main culprit is the recessed lights and the fiberglass insultation in our attic. It was amazing seeing how much heat was being lost up there!
Anyway, he suggest that I tear out all the fiberglass insulation, make foam board boxes to go over the recessed lights, put in baffles in the eaves and then blow in loose cellulose insulation. The main waste from this project will be all the old insulation. And there will be a bunch of it. What is the most cost effective and earth friendly way to dispose of it?
Thanks for any input.
10-25-2010 04:25 PM
Couldn't you just blow in the cellulose over the top of the glass? I would think the weight of the cellulose would compress the glass enough that it wouldn't make much difference if it ws there or not.
10-25-2010 05:44 PM
Unless the insulation is moldy, mildewed or wet, or if it will interfere with getting the R-value up (paperbacked instead of foil)I'd leave it.
It might be a scam to remove the old stuff (think Attic blankets) just to blow in cellulose.
Check on the why they want it removed and go from there.
10-25-2010 06:31 PM - edited 10-25-2010 06:38 PM
I totally agree with what others have said. Unless the fiberglass is moldy there's no reason to get rid of it. I have blown in insulation over fiberglass batts in my own home and have seen it done many times. Perhaps we're missing something whereby they want you to remove the insulation and do something more substantial than just blocking in cans. By the way, are the cans IC rated in that insulation can come into contact with them? If not I would rip them out and put IC rated ones in instead of making a box... seems like less work and lots more safe.
Anyway, back to your original question; fiberglass is not environmentally dangerous, it's basically silicone (sand) made into hair in much the same way as cotton candy is made with sugar. The cheapest way would be to bring it to the dump like any other garbage except that it will occupy a whole lot of space unless you compact it. In many jurisdictions garbage is calculated by volume and the insulation has a lot of volume. If you have the option you may want to try to dispose of it as weight, it of course has very little weight. You can also rent a dumpster. A 20 yard dumpster in my area is around $250 which includes delivery and pickup. I can't imagine you can't get a whole house worth of insulation (and a whole heck of a lot of other stuff you want to get rid of for compacting) in a 20 yard dumpster. Be careful though, at least in my area they get you for extra weight.
10-25-2010 06:45 PM
I also agree with everyone else and would just blow in over the top of it. But if you're adement about getting rid of it why not try giving it away to some one who is trying to insulate their shop?
10-26-2010 02:17 PM
Thank for everyone who replied. I contacted the energy contractor and asked him if I could use both and he said that I could. But he wanted me to put a layer of the cellulose below the fiber glass and on top. The reason he said was that for inslulation to be effective it needs to be touching the sheeting material below it. In New England, it is a common practice to insall "strapping" to the bottom of the ceiling joists. Strapping is a 3/4" X 2" board and it is used to screw the drywall to the ceiling. I guess that electricians also like it because it leaves a space to string wire. My home contains this material and it creates a bump in the fiber glass that allows air channels on the side that lead staight to the soffit. So that is why he wanted me to us the blown cellulose, to close that gap between the strapping and the drywall. Thanks for all your posts.
10-26-2010 05:49 PM
Dead air space is dead air space and that's what makes good insulation. Sounds to me like your "energy contractor" is trying to justify his fee and fancy title. I totally understand either removing the batts or blowing over the top of them. It will block the heat from escaping through the seams in the batts. But removing the batts to blow in insulation. Then reinstall the batts to blow in more insulation sounds like a load of crap to me. Your insulation will be just as effective if you don't remove the batts. Ask you "energy contractor" if the insulation would still work if you were to put in a suspended ceiling? Same difference as strapping.
10-26-2010 06:50 PM
As everyone knows dead air is a great insulator and really the basis for fiberglass and cellulose insulation. The key word here is "dead" air. If the air is escaping that's of course not good. I'm not sure though that you can't just move the batts from the edges towards the center and then just blow the cellulose where the batts were. I'm not sure the contractor was trying to rip you off. In at least my neck of the woods it would be too easy to get caught. Something as seemingly aggregious as that would certainly result in a complaint to the contractors license board.
10-26-2010 07:07 PM
And I'll throw in one more thought
What if you stopped those "channels" with foam at the outer walls?
removed the batts in the "outer" chanels and movved that insulation to somewhere else?