[greenbuild] Re: cotton insulation, wood treatments, durablock

  • From: "Jon Harrod" <insul8er@xxxxxxxxx>
  • To: <greenbuild@xxxxxxxxxxxxx>
  • Date: Tue, 10 Sep 2002 23:34:10 -0400


It does sound like a great project--with 8-10" walls and passive solar
design, you'll need very little supplemental heat.

As far as insulation goes, I'll echo Steve's statement that batt-type
insulation will only perform well if it is meticulously installed.  I've
come to the conclusion that if you're building wood-frame walls, cellulose
insulation is the way to go.  In addition to the dense-pack technique
mentioned by Steve, you may want to consider the "wet-spray" technique for
cellulose application.  Cellulose, mixed with a small amount of water and a
water-based adhesive, is sprayed into the stud cavities, where it sticks,
completely filling the cavity.  After a few days, the material dries out,
and you can sheetrock.

Although this approach doesn't do quite as good a job of reducing air
leakage compared to dense-pack, it provides higher R-value per inch (3.7 vs
3.2).  In addition, you can see the insulation before the sheetrock goes up,
so you know you have complete coverage.  I've seen this technique used in
walls up to 8" deep with excellent results.

My last piece of advice would be that in a small, superinsulated house like
the one you're building, be sure you are providing for adequate air
exchange, preferably through controlled mechanical ventilation, and also
adequate combustion air for the wood stove.  But that's a whole 'nother
discussion.

Good luck!
Jon Harrod


-----Original Message-----
From: greenbuild-bounce@xxxxxxxxxxxxx
[mailto:greenbuild-bounce@xxxxxxxxxxxxx]On Behalf Of Stephen Paisley
Sent: Tuesday, September 10, 2002 4:19 PM
To: greenbuild@xxxxxxxxxxxxx
Subject: [greenbuild] Re: cotton insulation, wood treatments, durablock



Your house sounds like fun--you'll have to invite everyone out to see it
sometime before it is finished so we can see how it is put together.

Robinson Lumber in Elmira--they also have an outlet in Odessa--used to
carry cotton insulation.  From what I've seen of it and heard, it takes a
bit of work to get it to "fluff" to its full rated thickness, but otherwise
works just like fiberglass batts--that is, not very well unless you have a
meticulous installation job, a good vapor barrier on the inside and a wind
barrier on the outside, and wall cavities that are all of uniform width and
depth with no wiring or plumbing in them.  The advantage of dense-pack
cellulose is that it completely fills the cavity and blocks air penetration
so that it performs really well even if you have none of these things.

      As far as wood preservatives, boric acid is said to work for wood
that will not be subjected to running water (which will dissolve the boric
acid and carry it away).  Tim-Bor is one brand, though when I last looked
into this about 5 years ago I was told that you needed to be a licensed
pest control person in order to buy the stuff.  This may have changed in
the mean time, though--it seems like I heard about an ordinary person using
it somewhere recently.  You can also get lumber that is pressure-treated
with ACQ--supposedly much more env-friendly than the  CCA-treated stuff
that is covering the American landscape like a green plague.  Using locust
or white oak or larch heartwood is the best way to go if you can, of course.

As for durablock, do you mean durock, the cement tile backerboard
stuff?  It's not too hard to work with, but is pretty expensive.  How about
a thick earthen or gypsum plaster on wood lath?

                  --Good luck, and don't let time pressure make you not
enjoy what you're doing (I myself struggle with this daily) ----Steve

At 02:08 PM 9/10/02 -0400, you wrote:


>Does anyone have any experience with cotton insulation?
>
>I am planning to insulate my new home with blown-in recycled celluse
>insulation, but would like to consider other non-toxic possibilities, in
>particular cotton. Does anyone have any information about where cotton
>insulation can be purchased?
>
>I also have alot of wood that I would like to treat and wonder about what
>non-toxic treatments are avaliable.
>
>Also, I am considering using "durablock" which is essentially like drywall
>but made out of concrete in smaller panels for the inside, south facing
>walls of my new house. I'm thinking these would absorb more heat from my
>southside windows and woodstove than drywall. Is this stuff difficult to
>work with? Is it hard to finish nicely? Too expensive? Am I crazy?
>
>If anyone has any company names, ph #s, web sites, etc. that offer
>information or products I would be very appreciative of your help.
>
>By the way, I am building a 1000 square foot, two story home, with the
>northside earth-bermed, the southside w/ plenty of glass, and using
>passive solar and wood to heat the house. The house is being built with 8"
>and 10' walls to be filled with cellulose or some other ecologically
>sane insulation. I am using a standard construction grade Pine with
>the exception of a few choice applications where I've used white oak (rot
>resistant) and custom-milled lumber (ceiling joists). The roof is metal.
>Electric will come from PV modules in a system being designed by Julie and
>Benj of Wood, Wind and Sun, Inc. I could go on-and-on describing the design
>features but can sum up the design as outwardly conventional-looking
>(sort of...) with components systems chosen with a priority for natural
>materials and energy conservation.
>
>I am hoping and praying that I'll be in the house by the
>first snowfall 'cause nights are getting cold, especially at my
>elevation (1,350).
>
>Likewise I miss the intellectual stimulation and sharing many of us
>enjoyed during last year's Sustainable Ithaca series and hope something
>like it may occur again. Also, I miss attending the Natural Builders
>Group's meetings and look forward to the day when my home is completed
>enough to allow time to attend once again, or even host a meeting!
>
>
>  ### burns@xxxxxxxxx ###

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