# How many bags of blown-in cellulose insulation do I need



## rschmiss (Mar 17, 2011)

I have 2000 square feet of attic with a with an R value of 25-- How many bags of cellulose do I need to bring it up to an R-value of 49 or 60???


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## Jackofall1 (Dec 5, 2010)

Hi and welcome rschmiss, to the best darn DIY'r site on the web.

Edit - Here is a guide to your answer - http://www.ehow.com/how_5896930_calculate-blown-insulation-coverage-attic.html

Lowes also has a calculator for the same purpose

Mark


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## dleaoh (Dec 25, 2010)

*It Depends on the Product*

There is no generic coverage chart for cellulose insulation -- or any other loose fill insulation for that matter. You will have to consult the coverage chart for the specific product you intend to install. On the chart you will find rows for R13, 19, 22, 30, 38 and 49. Some manufacturers provide additional R-value information. None of these rows will give you exactly R49 assuming an existing R25, but you can make a reasonable estimate. If your existing insulation is loose fill fiber glass there will be some compression if you put cellulose on top of it. In that case you may want to arbitrarily choose to install an additional R-30. The final insulation deck will cedrtainly be somewhere between R50 and R55.


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