Hi Everyone,
It is I, Janoahsh that asked this question, I don’t know who Neal or MD is or how they got into the conversation. I appreciate the responses as all being right in their own context. I have many megabits of insulation information accumulated over years of research going back to the late 60’s. I was looking through my files trying to find the maximum practically achievable insulation values and couldn’t find the references I quoted though I can remember them. I have many hundreds of files on all kinds of insulations. It surprised me how many of these included discussions involving Elf Nori.
First of all I stated double thin shell FC with continuous insulation, not Stud wall construction.
The 4” and 6” thicknesses are relative approximates and came from a study on refrigeration units with solid insulation cores with no other structural connectivity other than the insulation.
Let’s use foam as an example. At 4” urethane foam is at the high end of achievable insulation value. Twice the amount will only add a percentage point or two thus indicating little practical advantage. Taking R7, or whatever rating, per inch does not continue to apply after the first inch and becomes miniscule after 4”.
I will be taking advantage of all kinds of thermal mass heat storage but I am trying to figure how much papercrete it will take to gain a high 90’s % of achievable value.
As far as windows and other bleed offs are concerned, I acknowledge and am considering these as well.
I realize there are no exact answers to my questions and am just looking for some approximates.
Using pure paper without cement or sand is probably the highest insulation value and high sand and cement ratio to paper is probably much lower.
If I use a cement paper mix with no sand and minimal cement, can I achieve high 90’s % with less than 2 feet of continuous insulation? 1 Foot.? 3 Feet?
I understand that 4’ is better than 1’, but approximately how much?
From:
Sent: Thursday, January 24, 2008 5:50 AM
To:
Subject: [papercreters] Re: Insulation Value
I do not agree with your presumptions about insulation thickness.
> Urethane foam over 4" thick gives very little additional insulation
over
> what is achieved in 4".
>
> EPS over 6" shows little benefit.
>
While these rules of thumb may have been accurate at one time, for
typical stud frame construction, in a typical temperate climate in
the
builders and suppliers. Please quote your source for these numbers.
Who said it? Where? Do you have a website that we can see?
If insulation is getting inserted between studs in a stud wall, there
is a big limitation. The insulation cannot change the performance of
the studs themselves. The studs inherintly limit the thickness of
insulation that can be inserted. They also create an obsticle at
regular intervals where gaps in the insulation often appear. To
create great thicknesses using standard stick framing, builders would
have to design a double stud wall with a gap that could be filled
with insulation. It is prohibitively difficult TO CONVINCE
CONVENTIONAL BUYERS to pay the extra expense (at least nearly
doubling the framing costs). The long term economic considerations
about fuel reductions don't enter into that decision. Typical
consumers won't pay the extra when there is a cheaper house for sale
down the street that looks just as nice on the surface.
Papercrete builders do not need to be constrained by the same
limitations. Papercrete isn't traditional insulation, and isn't
often used in standard stick frame construction. This is a material
that can be both an insuator and a compressive structural component
of the structure. It requires a shift in thinking.
The old axioms listed above are outdated, do not apply to arctic
climates, and need to be completely reconsidered.
I will address the basic methodology for a cost/benefit analysis as
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