We are building a new home in WA. It is about 4000' including a 900' walkout basement and cathedral ceilings. We plan to use the recycled cotton insulation (first saw it on HGTV). It comes in an R-13 and R-19, si treated with boric acid as a fire retardent and repels insects. The plan is to use it throughout the house below grade walls, above grade walls and ceiling etc. Any problem with it throughout the house and is there any corrosive effect form boric acid on anything: wiring, plumbing , etc.?

As long as your code jurisdiction approves it use there should be no problems with using it.

But since your region requires a minimum ceiling insulation of between R-38-R-49, your walls a minimum of R-16 to R-21, and floors a minmum of R-19 to R-21, basements R-9 to R-11 and crawslpaces R-17-R-20....There are limited places where you can use it without using additional forms of insulation as well.

Thank you. The reclaimed cotton insulation is one of our attempts at "building green" as well as being something a little more friendly yo work with. I guess the bottom line question is the practicality of double layering the cotton insulation in areas where a higher R-value is needed; cathedral ceilings for example or is it wiser to go to a combination of insulations.

It's up to you whether you mix 'n match insulation types of simply double up on batts in some areas of the house like the attic where doubling up may not be hampered by the depth of framing members.

But elsewhere you'd almost certainly have to use multiple types of insulation to get the required R-rating that cotton or fiberglass cannot provide.

Takes wals for example. If R-19 is the maximum available for cotton batts and your code requires R-21 for walls, you will likley need to add rigid foam on the outside of the framed walls because shoving more cotton into the wall cavity will compress it and be counterproductive.

You would also want to make sure you don't have two vapor barries if you place one layer on top of or over another cotton layer.

Dear Mitch,
You may want to try http://www.bondedlogic.com for information on cotton insulation that is "green conscious". Their product is "ultratouch" sold in rolls. Hopefully their website can answer your questions. They advertise that their product meets the maximum R value. I'm also "green conscious.

If you want to use a "green" building product, then consider wet applied cellulose.

Cellulose is made almost entirely of recycled newspapers.

Cellulose provides one of the best all around R values per inch than any other type.

It is also very affordable.

Wet blown cellulose is applied as is icynene and asheres permanently to surfaces without the shrinkage problems of dry cellulose.