Hi -
I am building a small house and am acting as my own GC.  I am trying to be environmentally conscious both in terms of making it energy efficient and using materials that are less toxic - to me and the environment.
Is there a rigid foam and/or house wrap that is more "green" than others? 
Is there a preferred insulation that is both effective and "green"??  
I do not seem to be having much luck with Google.
Thank you. 
Nancy
NE TN 

You can use recycled foam board to be more green. Cellulose insulation is made from recycled newspaper and is probably the most "green" that you can get as far as insulation goes.

rigid foams are not particularly "green" in their manufacture, except that they are mostly air. They are very green in that they will last indefinitely and can reduce the amount of fuel you use to heat or cool your house. Cellulose is the greenest insualtion, but there are places such as under concrete floors where foam is only choice.

environmentally conscious - energy efficient - less toxic = cellulose

Rock wool is also a recycled product that's inherently non-toxic (and zero VOC), but I still prefer cellulose iin timber framed applications for it's moisture-buffering and lower air-infiltration aspects. Rigid rock wool used in soundproofing since it's inherently flame-proof, and can be used on interiors without ignition barriers, etc. I haven't heard of it being used as insulated sheathing for exteriors, but can't think of why it couldn't be used that way (with the exception of goods with vapor-barrier facers that might trap moisture.)

Using recycled rigid board is the way to go, if you can. Be sure to use goods appropriate to your climate (no aluminum or poly facers in cooler climes, to avoid trapping winter moisture from the in the wall, etc. Aluminum facers can be GOOD in cooling dominated climates though.)

Some forms of natural insulation include:

* Glass wool.
This form of natural insulation is made from sand and recycled bottles.
The silica forms fibers and are held together with a resin binder.
This form of natural insulation has excellent fire retardant qualities which gives your home added protection.
* Slag and rock wool.
This natural insulation also uses silica fibers but these are drawn from rocks rather than recycled glass.
* Cotton.
This type of natural slab insulation uses cotton fibers.
It does not have good fire retardant qualities and may need additional chemical treatment to give you the fire protection you need.
* Cellulose material.
This form of natural insulation uses cellulose from recycled newspapers and other similar paper products.
It also has a poor fire rating.