Subject: Re: 'Annotated Bucky'

From: [email-masked] (Nick Pine)
Date: 20 Oct 1995 04:27:39 -0400

dave suwala  <[email-masked]> wrote:

>>   Given that none of us can afford custom tooling for integrated 
>>   aircraft-like modular housing, we are left with a number of
>>   unexploited neat concepts to test and work upon.

The tooling was supposed to make the product less expensive.
Of course you have to build more than one product :-)
 
>    I suppose that this refers to the first of Bucky's housing concepts.
>    It was made of stamped sheet metal with a dome-like top
>    and suspended on a services pillar.

A pre-Dymaxion house, made from standard silo parts?

>    It must have been a disaster to heat and cool.

Well, energy was cheaper then. It seems to me that the least expensive
buildings today are still made of sheet metal, eg painted steel. Steel barns
and sheds cost about $5/ft^2 where I live, a lot less than wooden ones,
these days. But they probably leak air a lot, and how do you insulate them?
Spray sticky cellulose foam on the inside? Is that sufficiently fireproof?
Polyurethane isn't. Perhaps fiberglass, with Thermo-Ply or Drywall over that.
Or in the case of a shed, just a layer of polyethylene film over that. With
a layer of Tyvek next to the steel to control air infiltration? Foil-faced
bubble pack has also been used to insulate steel buildings.

>    Certainly, this would have been expensive in today's terms
>    (custom tooling for integrated aircraft-like modular housing)

Tooling of some sort can help make houses less expensive, and while the
tooling costs more than a single homeowner would pay, it may still be within
reach of a small company. Computers help too, these days. For instance,
engineer Lyle Rawlings at (609) 466-4495 says that Avis Modular Homes in
Avis, PA, near Williamsport, use simple tooling, jigs, etc, to make
practically any sort of custom modular house, within limits, starting from
a sketch, with a relatively small fixed $500 design fee. Once they get started
building the house, it takes about 5 days for it to move through their
production line, another 2 days to put it up on a site, and 2 or 3 more
weeks to hook up the plumbing, etc.

The Avis house is better than one built on site. For instance, these houses 
are said to have an air infiltration rate (air leakiness) of 0.25 air changes
per hour at 50 Pascals of pressure, ie about 0.0125 air changes per hour
in average winter weather (dividing that 50 Pascal number by 20, using the
formula in Nisson and Dutt's _Superinsulated Home Book_) vs. 1 or 2 air
changes per hour for an average house. To put this in perspective, a
30' x 30' x 16' tall house contains about 16,000 ft^3, and 1 Btu heats
about 55 ft^3 of air 1 degree F, and a gallon of oil as burned in a house
today contains some 100,000 Btu, so an Avis house in Philadelphia's 5500 F
degree day winter heating season would need about

5500 x 24 h/d x 0.0125 x 16,000/55/100,000 = 4.8 gallons of oil a year

to heat the air that naturally leaks out of the house, while an average
house that size would need closer to 400 gallons of oil a year, just to
take care of the air leakiness, even if it had perfect insulation. The
Avis house would probably need some sort of deliberate ventilation, eg
an air-air heat exchanger, since the natural air leakiness would only
provide about 3 cfm of outside air in the winter. 

These houses are said to cost less than a house built on site, as well,
even with low local labor rates.

>    I have been in a geodesic dome recently and this type of structure
>    does bring questions to mind.  Who can tolerate non-Cartesian walls
>    from which you cannot hang pictures?

It helps to think round, in the interior design phase, eg pie-shaped rooms 
with radial walls. If there must be square spaces, eg kitchens or living
rooms, those often work better in the center.

Maybe you get a different feeling when you live in one of these, vs. just
visiting one. When I visit a dome, I know in my head that it has lots of
floor space, but it feels small to me, perhaps because I can see the
boundaries of the whole structure from the inside, unlike a conventional
house, divided up into rooms. I did a little farming on a 126 acre plot
30 years ago, and the open fields looked fairly big to me then, but when
I revisited the farm last year, the owners had allowed it to return to
nature, and as I walked around the former fields on trails through woods
with 6" diameter trees blocking my view, the space felt huge, and very
private. Much nicer, it seemed to me.

>    ...when you erect the vertical walls to divide the interior spaces,
>    does that not destroy the merits of the dome for convection
>    heating/cooling?

I wouldn't think so. But the floors might, unless they had some holes.

Nick