Cob: insulation facts

[Sojourner]

H. Wayne said

> Good points.  Trying to make heads or tails of this
> insulation issue is a bit of a job.  Fiber glass is
> not always a good solution.  Solar, mass, thermal mass,
> dead air space, and various fillers (paper included) do
> not always seem to hold promises made with given R-values. 
> I am beginning to think this R-value stuff was really a
> bunch of wallawalla intended to make some money for a
> few manufactures of expensive insulation materials.

I don't think you're far wrong.  I don't think the tests that give us R
values reflect the be-all and end-all of insulation, thermal gain, and
heat loss, not by a long shot.  As I recall, the R-values they come up
with do NOT reflect the true insulative value of fiberglass and other
such substances as they are actually commonly used and installed - they
are ideal values, not real-world values.  They don't take into account
things like thermal bridges which are common in most standard
construction, and bypass the idealized perfect insulation.

> The bottom line is, if you can make heat or cool air,
> and hold it in the structure for at least 6 hours without
> thermal effects transferring from the outside, you are
> doing great. 

Yup.  I agree totally.

> The only one that offers the highest degree of resistance
> to thermal energy transfer is dead air space.

By dead air space, you don't mean just a big air gap, do you?  Because
the value of insulation is in having lots of LITTLE air spaces rather
than one big one.

I probably can't explain it properly, but does that make sense?  It's
like having a bunch of airlocks between you and the vacuum - just like a
lot of air locks protect you from loss of breathing space, lost of
little air gaps protect you from losing heat to the outside in one big
rush.

It has to work its way through all those separated air spaces first.

> The best thing to do is talk with folks in your area
> that have found a system that works.

Unfortunately, almost everybody has moved to fiberglass batts and stick
houses over the past 40 years or so, so that old knowledge of
alternatives to the pink (or yellow) stuff is getting increasingly hard
to come by.

And people, even people on this list who are undoubtedly GENERALLY more
open minded about alternative insulations, have been socialized into
being afraid of some of the older methods of insulating a home, such as
straw or sawdust.

> There is no magic bullet for all that I know of

Exactly my point, which I think you are making very well.

> I myself think the foam systems hold great promise, but plastic
> allows thermal degree or energy movement. 

There are still problems that some people cannot ignore involving the
question of how these substances are manufactured, as well as concerns
about outgassing and what gases may be release in a fire.  Like you
said:

> Then there is the issue of the source of those plastics, oil.

Most people today who die in fires die of smoke inhalation, not being
burned.  Often they are found seemingly peacefully asleep, totally
untouched by fire.  They breath in poisonous gases released from
petrochemical based plastics now ubiquitous in our homes that were
totally unheard of 50 years ago.

Personally, the problem I have with the foamed on stuff is the fact that
it requires expensive equipment and a level of skill to apply, neither
of which I have, so it becomes just another job you have to pay somebody
else to do.

Holly ;-D