blown-in vs dense pack cellulose

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blown-in vs dense pack cellulose

Postby homeowner » Wed Mar 16, 2011 3:44 pm

I have estimates to insulate the walls using both methods...the dense pack cellulose is almost twice as much as the blown-in. I have read that blown-in might settle over time while dense pack does not. Does the benefits of dense pack justify the higher installation cost? The fact that I'm also redoing my vinyl siding using Crane siding w/ the 1/2 in. insulation board attached and Tyvek wrapped...would it even matter if the blown-in cellulose settles a bit over time?

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Re: blown-in vs dense pack cellulose

Postby bigblue » Tue Apr 05, 2011 9:59 pm

Settling can be a big deal if it settles a bit depending on what part of the country your from. Settling in walls can create a moisture problem, which can lead to bigger problems. It's a real big problem if you live in the north.

Can you give me a few more details please? Are the cavities open or are you filling the wall?

If it's open walls, Wall spray is the way to go with cellulose or the new Cotton batt that just came out.

If you are filling a wall it's all about density. The density of the cellulose should be between 2.3 lbs up to 3 lbs per cubic foot to prevent settling. Don't look at the coverage chart on the bag, its all about pounds of cellulose in your wall. Most coverage charts are for attic coverage.

If you have the wall area minus the studs you can calculate how many pounds the install should use per wall. If he is in the range stated above you should be good to go. And if you really want to make sure the job is done right, hire someone with a inferred camera and shoot the walls.

Please send me a e-mail if you need any back up info to provide your installer.
Over 30 years in the Cellulose Industry. Head of Product Development.
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Re: blown-in vs dense pack cellulose

Postby Jackofalltrades » Sun Apr 24, 2011 10:59 am

Cellulose needs to be packed between 3.5 and 4.0 lbs/sq-ft to prevent settling, but also to give it the air sealing qualities that every homeowner would want. The 3.0 lbs/sq-ft referenced above would not meet most state weatherization agency requirements.
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