Blown-In Insulation...Is it Really That Cheap???

Old 04-24-12, 04:41 AM
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Blown-In Insulation...Is it Really That Cheap???

Let me first say that I haven't had any quotes yet. I had always assumed this stuff was expensive and only recently opened up to it. A quick google search gave plenty of "cost estimators" and plenty of posts from people getting quotes.

I'm shocked. In central Massachusetts it looks like the going rate is about $0.80 per square foot!!! Considering I only have 415 square feet to do....Thats cheap!

I have a 1.5 story colonial with slanted ceilings on the second floor. There is existing blown-in insulation in the rafter bays but it was done poorly. Its airtight and there isn't a way for the roof sheathing to breath which has led to some moisture issues.

I need to hire someone to suck the existing blown-in out with an insulation removal vacuum, install foam rafter bays, and then blow some new insulation back in.

Its a more awkward than normal job since the headroom is tight in the attic and you'll be on your hands and knees all of the time. But even if they quote me double the normal rate.....that's still only $660!

Of course they will have to also charge me to suck the old stuff out...but I imagine that's easy work. If the numbers out there are true...I might just pay someone to do the work for once!

Am I nuts for thinking this may cost around $1,000 or less?
Old 04-26-12, 04:37 PM
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You are right, cellulose insulation is cheap. It's just ground up newspaper that's treated to make it resistant to mold, insects, rodents, and fire. I actually just got done insulating an old house with the stuff. There is actually a way to blow it into all the hollow wall cavities. All you need to do is drill a 1 inch diameter hole. Also, I went to a local lumberyard that lets people use the blower for free if they buy the insulation from them. It cost me very little to insulate the whole house. This is the best home improvement a homeowner can make because it will pay for itself many times over. So, yeah it probably won't cost that much.

As a side note, do you have gable-end and roof vents on your house? This would also let your attic breath but you wouldn't have to remove the insulation. The cooler air enters the gable-end vent and exits through the roof vent. There are also solar powered roof vents to improve airflow even more.
Old 04-27-12, 04:28 AM
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This would also let your attic breath but you wouldn't have to remove the insulation.
The problem is that the underside of the roof deck needs the airflow, not the attic. There was an article written on not too long about dense packing cellulose into rafter bays. It turns out it doesn't so well because of the problems the OP has. For this type of installation to work, you need too keep water vapor from entering the rafter bay. The cellulose just isn't dense enough to stop that, and even putting up plastic sheeting isn't enough. There are always penetrations through it for lighting, nails, screws, etc. Those allow water vapor to pass. When the water vapor reaches the roof deck in the winter, it condenses and causes rot to occur.

BSI-043: Don't Be Dense
Old 04-28-12, 06:42 AM
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home depot sells a leaf blower that also works as a leaf vac you can buy one of those and do the removal on your own. the big this is venting the attic space the best is poly vents in every rafter run and a powered fan pulling air out of attic. the only form of attic insulation that wont need ventilation is spray foam which in my area goes for about $1.80 a sq ft and will do far better than any other type of insulation

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