Question about insulation

Hi Chris and Linda,
Thanks for taking questions!
I am looking to use natural building methods in central Massachusetts to insulate a wooden shed such that I might be able to put an air conditioner and a coolbot in there to make walk-in storage for crops on a low budget. I am wondering what the best materials will be: cob? Straw bale? Earthbags? Any other General construction advice is more than welcome of course.

Thanks!
Sam

[size=18]Hi Sam, we use an above ground plastered straw bale "cellar" at Sage Mountain Center for our food/grain storage. It has performed very well. Using an air-conditioner for your cooling turns your shed into a "refrigerator", hence you want insulation (straw bales) over thermal mass (cob, earthbags). All newer cooling appliances like fridges and freezers beef up insulation to help them become more efficient... that is what you need. For your shed I would say that the straw bale option is very doable depending on a few factors. 1. if the interior space allows, you could put the bales on the inside of the shed and plaster/seal the interior. 2. If the bales are to the outside of the walls you will need big enough overhangs from the roof to be sure the rain run-off does not soak the plastered bale. I like gutters for this reason. Also, an inexpensive foundation for the bales could be contructed from pallets or pressure treated wood. You're only looking at about 5 bales high so the weight of the wall is not a bid deal. Chris.[/size]

There are many options for cooling other than freon cycle refrigeration. Water is one easily developed source, but many exist if you get creative.

Here we are splitting the water main in a heavily insulated closet on the north wall of the basement and re-using a walk-in cooler door.

Chris,
Thanks so much for the info! The interior space is not huge, so putting full bales on the inside is probably not the best idea. I will have to look at the space again on the outside of the building to see what it would take to insulate it that way. Are there any other materials that do not require as much physical space as straw bales that I could use inside? Do you recommend any sort of cross-over material between the nasty pink fiberglass stuff and something healthier and more natural?

Bill,
I appreciate the tip and your example. This particular building has electricity but not plumbing. Any other out-side the box ideas come to mind for you? Also, I love the quote on the wall! HA

Cellulose is a nice product and has almost double the r-value of straw, per inch. Thus you would need half the thickness.

A few 2x4's, a little drywall and blow the cavity full.


Not a bad do-it-yourself proposition.


troy

For stud cavity insulation, I only use 2 products, each excellent, but with different characteristics and uses; dense packed cellulose or stone wool from Roxul.

You can see the Roxul under the XPS foam in the photo. I use Roxul anywhere there might be a little moisture like a walk-in cooler. I would be using the Roxul insulating sheathing as well instead of nasty foam, but I can't seem to get any out here in Utah.

For cooling, try evaporative processes since you don't need cold cold. If you do go for the freon, don't use those cheapy through the wall AC units as they are terribly inefficient when compared to a unit designed for this application.