[ExI] plastic house, was: RE: Trying for a minimum technical comment

giorgio gaviraghi giogavir at yahoo.it
Wed Dec 19 10:29:38 UTC 2012

we are actually producing them polyurethane panels with structure embedded including all <utilities . In 3 days yo build a home and it cost 50% of conventional <onesùGiorgio

 Da: spike <spike66 at att.net>
A: 'ExI chat list' <extropy-chat at lists.extropy.org> 
Inviato: Mercoledì 19 Dicembre 2012 8:18
Oggetto: [ExI] plastic house, was:  RE:  Trying for a minimum technical comment
>... On Behalf Of Mike Dougherty

>>...  I can imagine building homes out of big Styrofoam blocks of some

>...On one hand, they blow away in the first Nor'easter.  On the other,
renovations can be done with a serrated knife and a glue gun.  Mike

Hmmm, Styrofoam was a poor choice of words, because it reminds one of the
minimum density versions used in disposable picnic coolers and packing
material, but that isn't really what I had in mind.  Rather if we had
stabilized cellulose which is super cheap and abundant, really not much more
than straw, then mixed it with polystyrene as a low cost matrix, then we mix
the two and pour it into a custom mold, similar to the way you do a cast
concrete structure, with a Freon based expanding agent to expand the foam to
perhaps somewhere around 2.5 to 1.  Pour, expand, trim to the proper
dimensions and there you have it.

The mold would be just particle board with a thin sheet of aluminum on
either side, so it gets its strength from the aluminum.  Every meter or so
spacing you have some kind of thru-bolt spacer rivet, about half a cm
diameter steel to keep the two sheets of the mold from bowing out when you
pour your polystyrene/cel-fiber/foaming agent mixture between the two
laminate boards spaced about 10 cm apart.

There would be drawbacks to that arrangement of course.  For instance, the
electricity and plumbing would likely need to be added after the fact and be
external to the structure.  But not necessarily.  Perhaps they could be cast
into the structure.

In any case, I can imagine the insulation value of such a structure would be
terrific.  Polystyrene is a lousy conductor of heat.  Then add the fact that
it is a closed cell foam, and you have a good insulator.  Termites will not
eat the stuff, can't.  It will not break down from UV, because the outer
layer is a sheet of aluminum.  Won't rust, won't oxidize much in our
lifetimes.  So my estimate is 2 mm sheet of aluminum, cm of particle board,
2 mm sheet of aluminum, 10 cm of expanded polystyrene and cellulose fiber, 2
mm Al, cm particle board, 2 mm Al.  Estimated insulation value about R30,
but I need to get down and do the calculations on that.

If one really likes a traditional-looking house, we can suppose putting
stucco on the outside, if we attached some wire lattice.


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