On Sun, Apr 26, 2015 at 4:32 PM, Bruce Johnson <johnson@pharmacy.arizona.edu> wrote:

> On Apr 25, 2015, at 11:13 PM, Richard Aiken <raikenclw@gmail.com> wrote:
>
>
> What I'm considering is pouring inner and outer walls separated by a large gap, chemically sealing the walls inside and out against air/water infiltration, then pumping the air pressure within the gap down toward a vacuum.
>
> Essentially, I'd be building the house as an ENORMOUS Dewar flask.
>
‘
I doubt the increase in insulation would be worth the extra costs (both initial material and ongoing pumping) to beat something like this: <http://www.preciseforms.com/insulated_easiwall.html>.

Perhaps. But I'm going to be building at least this first increment in slow stages on the cheap, using slipforms and incorporating random large chunks of granite rock.

(Some years ago, one of my neighbors started trucking in loads of broken granite and dumping them on a stretch of creekbed which lay beside the city street we live on, in order to bring it up to grade (and likely build a craft shop thereon to rent out - we're located in the Great Smoky Arts and Crafts Community). But then someone got a court injunction against him for destructrion of wetlands. Needless to say, said neighbor didn't spend the money that would have been required to remove the already-dumped rock. But he's told me I can use whatever I want of it, for whatever I might need.)

But my sister had to have some water line replaced a while back and I gathered up the old (1960s) line, which is one inch steel piping. I figure I can lay lengths of this through the outer wall into the inner gap and then later use these to blow expanding foam into said gap.

Oh! I did go to that site. They have a video there wherein they shoot a Barret .50 cal at a section of their wall from a range of ~15 feet. It took four rounds fired at the same point before both 4" walls were penetrated.

NOTE: The window panes will initially be just regular glass set into site-built frames (see below). But as I get the money, I'm going to replace them with bullet-resistant glass.

Cracks in the concrete form earth movement over time would break the vacuum anyway.

If it's cast as a single block (which the expoxy bonding of the different pours should allow - the bond has a higher strength rating than the finished wall) and it's poured on subsoil rather than fill soil, settling should be uniform.

The walls are rarely your problem spot for insulation, anyway, given that you put gigantic holes in the things for windows and doors :-)

One door penetrating the Dewar gap on each of two levels, plus a light well (built of glass blocks set into the pours) in the rear of each level. The windows (and patio/balcony door) are all on the south side and won't involve penetration of the Dewar gap; the window wall will be a separate structure set between the solid concrete walls/floor/ceiling.

Richard Aiken

"Never insult anyone by accident." Robert A. Heinlein

"A word to the wise ain't necessary -- it's the stupid ones that need the advice." - Bill Cosby

"We know a little about a lot of things; just enough to make us dangerous." Dean Winchester