Blown in attic insulation

MoNovember 20, 2007

If you got blown in attic insulation, did you choose fiberglass or cellulose, and what influenced your decision?

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Go with cellulose.

- won't hold R-value with decreasing temps.
- lets air wash through it, ruining it's insulative value.
- won't seal air leaks like cellulose will.

    Bookmark   November 20, 2007 at 4:59PM
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Cellulose is also much easier to clean after finishing---and regardless of how sanitary the installation is---there WILL be cleanup.

    Bookmark   November 21, 2007 at 1:10PM
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Before you install your attic insulation take a walk in your attic while there is light inside the house.
Look for areas where you can see the light in the attic from the living space.
Take time to seal these areas before you insulate.
You'll never have the clean access that you have now to seal these air leakage areas. Caulk, masitc tape & foam will seal most of these leakage areas.
Once you have as airtight of a barrier between you & the attic space the easier it will be to heat & cool your home.
And once these areas are sealed the insulation performs much better because air is not moving through the insulation & robbing it of its insulating value. The air tight sealing will also minimize the 'dust' from the attic which is all too often cellulose dust entering through holes between attic & conditioned space.

Take a look at your a/c supply boxes. They should fit tightly to the sheetrock with no raised areas or gaps.
If you find that you can see light around the cut for the box..seal it. Use a mastic caulk like irongrip by hardcast.
Mastic tapes are easy to use & provide a long lasting seal
you can purchase these products at a hvac supply house.

best of luck to you.

    Bookmark   November 21, 2007 at 8:58PM
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I had blown-in insulation installed in my attic only to find that over a year my electrical consumption consistently went UP 1/3 on a monthly basis. I later read an article that stated "if air spaces were not sealed prior to adding insulation," this often happens. The recommended fix was to roll back insulation and seal all air holes. Obviously this is impossible with blown-in insulation. I'm more than a little surprised that the company who did my insulation work didn't highly recommend this procedure before proceeding with the job. It looks as if I simply threw away $2,000. Anyone have any solutions at thiis point?

    Bookmark   April 25, 2011 at 9:36PM
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seal the holes from inside the house.
recessed cans can be retrofitted with air tight inserts
cuts between sheetrock and a/c supply boxes can be sealed with mastic tape
also oversized cuts at bath fans, and stove vents can be sealed with mastic tape.
caulking does not seal sheetrock cuts.
if you have ceiling moldings they are often hole cover uppers where the ceiling and walls meet is often a sizeable gap. caulk top of moldings to ceiling bottom of moldings to walls.

have an energy audit with a blower door test..duct test.
make sure that they show you where the leaks are.
free audits often do not show what you need to know about your house, and I'm hearing of companies who do these free audits that don't show the ho the leakage, but bid the job to fix.
hire an independent auditor to test before and identify leakage..get recommendations as to how to seal the leakage sites..get the sealing done or diy..have indpendent auditor to come back and retest.

if you have a blown fg you can find the leakage by looking for discolored fg. as the air moves thru the insulation it leaves dust particles these dirt trails are above leakage sites.

are you sure that nothing else is going on to increase utility costs?

you may want to start your own current thread rather than use a years old thread...

best of luck

    Bookmark   April 30, 2011 at 10:03AM
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