As poverty is not green, a world of over six billion people can accommodate them greenly only if we both increase global wealth and find new building and construction forms, preferably those that will accommodate multi-story and multi-unit structures. Out of today’s welter of possible new technologies, a few will emerge as market leaders, and the jostling for visibility may be the ulterior or even overt motivation for this bold attempt to put a new form of concrete literally on the map, and on the Google Earth imagery, as reported in this Springfield (MO) News-Leader article:
An acre and a half under one extended roof
Highlandville — At 72,000 square feet, a gigantic private residence being built south of Ozark
is stirring plenty of talk — at home and far way.
That is 1½ acres of house floor area, bigger than many people’s lots.
The ultimate in privacy, a square mile to call your own
Pensmore, which sits on 500 acres, has been in some stage of construction since 2007, said Todd Wiesehan, planning and zoning administrator for Christian County, adding he believes it will take another year or two to complete.
The technology is impractical if that is the maximum pace of construction; more likely, the builders are using the construction site as an enormous parallel experiment, working through the particulars of how to improve their new form of concrete.
Not made of concrete – Chambord, one of the greatest of French chateaux
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| Steven Huff |
It’s not clear why Huff is building such a large home – messages left at his
office were not returned –
As the schematic clearly shows a French-style chateau, perhaps the reason is simply that Mr. Huff would like a really, really big house that is also a showpiece for his concrete-forming company.
Modeled on Chambord and Azay-le-Rideau
– but a website does try to explain its existence, much to the relief of Wiesehan.
The website says this:
Pensmore is a laboratory for exploring different methods of creating and
storing usable energy that can be applied on a broad scale across commercial
and residential structures.
Over time we will be revealing more details about the creative
implementations that are giving reality to the vision.
Pensmore will be marketing one lives in.
But what some people may not be aware of is that the home is also being
built to show off new technology created by Huff’s company and the Helix Corporation.
As I posted regarding the $300 House initiative, to create the billions of new and larger homes we will need – yes, billions – we must develop new building forms that are low-skill, low-tech, readily adaptable, and using commonly available and inexpensive indigenous building materials. Concrete is one of these with great promise. You make it from sand, of which the globe has plenty, you can pour and form it, and when it sets it becomes incredibly strong.
Pour the concrete, stick in the rebar
Unfortunately, like other baked materials (bricks, adobe), concrete is brittle, and cracks into long and irreparable fissures, so it must be reinforced with a fibrous or tensile material – straw, rebar, or something else.
Because the Helix product is poured into concrete, it costs less than using rebar, though it can be used along with rebar for additional reinforcement, Pinkerton said.
Finding a better ‘something else’ might just be the key to expanding dramatically concrete’s value as a building material, especially if the additive increases insulation, air sealing, and heat reflectivity.
Pensmore’s structural shell, based on the super insulating TransForm system by TF, is comprised of continuously reinforced high performance poured-in-place concrete. Concrete reinforcement begins with conventional rebar, but for Pensmore we decided to supplement with Helix steel fiber from Polytorx. The resulting concrete is both stronger and more ductile in the face of the whirling winds of a tornado, or other natural disasters. The TransForm/Helix combination is surprisingly cost effective; a small increment in cost yields a very large increment in safety, durability and energy efficiency.
Wall forms at Pensmore: not the air spaces and styrofoam
The partnership of TF Concrete Forming Systems and Helix is to show
that a house can have that durability, yet look aesthetically pleasing.
Ideally – and quite probably – the Helix product can be patented, and if its manufacturing costs are low, or it can be manufactured around the world, then its business royalty and licensing value could be enormous – well worth the cost of a showcase home.
Wiesehan, planning and zoning administrator for Christian County,
is fielding calls from all over the U.S. about the massive home.
“I’m really happy (about the website),” Wiesehan said. “They had talked back in
March about trying to create a website so they could put some factual
information out there.”
Multiple different wall joins and angles, perhaps to test water seals
Presumably the developers are also exploring the several issues attendant upon a poured-and-baked structural material, including:
HVAC openings left in the wall forms
- Whether and how the post-constructed material can be shaved or penetrated.
- How it handles the joins of windows, doors, and entry/ egress points.
- How it can be built upon later.
- How it handles the home settling, or expansion/ contraction associated
with heat, cold, wind, and wet.
Pensmore: forming window apertures by pouring concrete around them
All the speculation over its sheer size — once completed, it will be
one of the largest homes in the US – and that it’s being made of
concrete has caused plenty of rumors to go around, Wiesehan said.
Throughout human history, many structural walls have been built using a sandwich or Eskimo Pie approach: two surfaces (one exterior and one interior) of a more expensive and durable material that hold a less expensive fill like aggregate, soft stone, wood, or Styrofoam.
Interior walls, showing Styrofoam, concrete, rebar, and framing materials
According to the TF Concrete Systems’ website, the company’s
new concrete forming technology adds flexibility to pour super-insulated
walls with a product that is lighter, lower in cost and more comprehensive
than other forming systems.
Typical sandwich wall
Luke Pinkerton, founder of Michigan-based Helix, said his company
partnered with Huff and his company to build the home just off Woods
Fork Road east of U.S. 65, a few miles south of Christian County EE.
Huff used Pinkerton’s steel reinforcement product in the insulated
concrete, manufactured and distributed by
TF Concrete Forming Systems, to build the concrete home.
Garages not visible?
The proof of any housing system, as Messrs. Huff and Pinkerton know, must be in the living.
The idea was to create a home that uses very low energy, as well as
having strong resistance to tornadoes, hurricanes, earthquakes, fire, f
lood and insect damage, Pinkerton said.
The best green will be low-tech, indigenous-material green, and this sounds promising.
“What we’re able to do is develop a home that has very, very
good insulating properties for heating and cooling,” he said.
“It’s very robust and strong.”
According to the website, “Pensmore is built to protect its inhabitants
even in the midst of an F-5 tornado.”
Aftermath of an F-5 tornado: Greensburg, kansas
For reference, an F-5 tornado (terrifying video here) normally results in “strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel reinforced concrete structures badly damaged.”
Although tornados may be the worry in Missouri, the more global threats are hurricanes and tsunamis; still, if the home can stand up to the F-5′s 260+ mph winds, it should be able to handle even a Category 5 hurricane’s 155 mph winds.
“What Helix is able to do is provide reinforcement throughout the
concrete … so if a tornado were to hit it, it will keep that
concrete together,” Pinkerton said. “In essence, the
whole house is a storm shelter.”
What you should bury next to your house if you live in a tornado zone
If so, and if affordable, then this is a significant advance in building technology.
Pensmore is a prototype of what the group hopes to be the
future of construction, as well as residential construction.
“The perception is that wood-frame is the only way to build a
residential home,” he said. “If I was going to build a new home,
I don’t see any reason why I’d build with wood. There’s no
reason to build a wood-frame home. A concrete home just makes sense.”
Wood homes proliferated in America because in America, wood is plentiful and therefore cheap both to acquire and to transport. In Europe, which had built out its forest capacity by the seventeenth century, wood gave way to brick and stone. Now to concrete?
Pensmore’s ground floor: framed and not yet poured
As much attention as the Pensmore home is gaining for its size, the
Helix product is also beginning to attract attention,
especially after the Joplin tornado.
“We have customers that make storm shelters with Helix,
and we’ve had a lot of increase in calls in that area
where all the (storm) damage has been,” Pinkerton said.
Building the modern chateau: Pensmore crew
