Ozarks house to be among largest in U.S.

Old substance, concrete, gets high-tech engineering

  the72,000 square foot  Pensmore Mansion located between Springfield and Branson Missouri.
the72,000 square foot Pensmore Mansion located between Springfield and Branson Missouri.

HIGHLANDVILLE, Mo. - Steven Huff of Virginia is building a second home in the Ozark Mountains. At 72,000 square feet, it would be one of the largest residences in the United States, with 13 bedrooms and 14 bathrooms.

Huff’s house would be bigger than William Randolph Hearst’s castle at San Simeon, Calif., Bill Gates’ mansion in Medina, Wash., or the White House.

It’s more than just a big house, Huff said. When finished in 2013, it will be a showplace, an example of how large structures can be built using aconcrete forming system that he developed. Huff claimed the house will be energy efficient and able to withstand an EF-5 tornado. The code refers to the Enhanced Fujita scale of tornado severity.

He calls the building Pensmore, from the French root word for “think” and the British root word for “more,” translating to “a more thoughtful way to build.” It is a combination of French and British architectural styles, resembling a French chateau, on a hilltop between Branson and Springfield, Mo.

While building a concrete barn at his home in Virginiathree years ago, Huff became interested in the ancient construction material.

“My background, I’m more of the eccentric geek,” he said.

Huff had sold his software company, Overwatch Systems, but was still doing some consulting for the company. With two physics degrees, Huff saw ways he could improve on the system that was being used to form the concrete walls of his barn.

Concrete walls are built using interlocking blocks made of polystyrene foam or other materials, often stacked together vertically with concrete poured into the hollow part. Reinforced steel bars are added to make the walls stronger.

OLD METHOD HAD PROBLEMS

But Huff saw consistent problems with the traditional method of concrete wall building.

For one thing, the insulation was too thin, contributing to frequent “blow outs” that occur when the poured concrete breaks the wall of the insulation. Huff fixed that with polystyrene insulation that is from 4-8 inches thick on the outside of the wall, which also helps with energy conservation and keeps the concrete from getting wet. On the inside of the concrete form, Huff uses a three-quarter-inch layer of rigid insulation to hold the concrete in place.

Also, Huff incorporated a rigid rail system to keep the blocks aligned and the walls straight.

“Pensmore is, architecturally speaking, the perfect test site for the product because it will offer various heights of walls from 4 feet to 32 feet tall,” according to a document from Eva V. Van Brunt of Los Angeles, Pensmore’s spokesman. “The building has multiple different-angled corners, arched windows and even different styles of walls.”

The walls, which already have been constructed, look fine, said Huff.

“The walls are laser straight and true because the forming system is rigidly locked together,” he said. “We have now formed 2 miles of wall without a wall system failure, blowouts or tilting of the walls.”

Huff’s barn was being built with a vertical concrete system from TF Concrete Forming Systems Inc. of Green Bay,Wis. Since TF Concrete had patents on part of the process, Huff decided to invest in the company so he could help improve its system.

He worked with Gerald Spude at TF Concrete to come up with the forming system he’s using at Pensmore. It’s called TransForm. Huff became majority owner of TF Concrete and chairman of the company’s board.

The concrete blocks also incorporate small, twisted steel wires that strengthen the walls and help them withstand tornadoes. Developed by Luke Pinkerton at the University of Michigan, the steel fiber insulation is called Helix. It was made to help buildings withstand earthquakes and explosions, according to pensmore.com.

WALLS SHOCK-ABSORBING

“This makes our structure more resistant to extreme weather and disaster conditions, allowing its concrete walls to absorb shocks and bend with them instead of breaking away from the steel rebar that reinforces it,” according to the Pensmore website.

Huff decided to make the mansion a laboratory.

“I was planning the house anyway, so I decided to design it around the new system,” he said. “I wanted to prove thatthe system would apply on a commercial scale. It’s easy to build a small home out of it.”

Huff said local building regulations made it easier to construct Pensmore in Missouri than Virginia.

It costs 5 percent to 10 percent more to build with concrete, but the structures will last “forever” and the energy savings will offset the construction cost, Huff said.

“It will last thousands of years,” he said. “Bugs don’t eat it.”

Concrete was used to construct the Parthenon in Rome, a temple built between 118 and 125 A.D. that is still standing, Huff said.

“The secret to making concrete was lost in the Dark Ages and wasn’t rediscovered until much later,” said Huff. “I’m not sure if they know how the Romans made it.”

Huff began construction on the Pensmore project two years ago. First, Huff had to build a road to the site and a bridge over WoodsFork Creek.

After a year, construction began on the house, but by then rumors were flying. Bloggers theorized that there was a bunker underground already, but there’s not, Huff said. He had kept the project secret for as long as possible because of patent applications for the concrete forming system.

“They filed a building permit in 2008,” said Lena Cheney, code enforcement officer for the Christian County, Mo., Planning and Zoning Department.

Initially, people assumed Brad Pitt, the actor from Springfield, Mo., and his wife, actress Angelina Jolie, were building Pensmore, said Cheney.

“But no,” she said. “It’s forthe Huff family. There were a lot of questions, but now that they went public with it, we’ve had no complaints. They were just curious.”

A FAMILY PROJECT

Originally from Brunswick, Mo., Huff wanted to build a second home in the Ozarks, and he wanted it to be able to withstand tornadoes. Huff bought the 550-acre site four years ago.

Pensmore is very much a family project. Huff designed the house, and his daughter Susan Huff added the interior architectural features. Huff’s brother Bob Huff is the general contractor.

Tom O’Neil of O’Neil Architects in Virginia served as a consultant. Cates Engineering of Virginia served as a consultant for the structural engineering.

Two smaller structures have been built in Virginia using TransForm: an addition to Huff’s house and a fellowship hall for Bethel Orthodox Presbyterian Church in Leesburg. Each was about 8,000 square feet.

Pensmore will harvest solar heat energy during the day and store it within the steelreinforced concrete shell of the house, Huff said. Inside the walls will be plastic tubes full of antifreeze that will transmit radiant heat.

Pensmore will be able to store approximately 65 million BTUs of energy while the sun shines and slowly release that heat into the interior at night and on cloudy days, Huff said.

“It’ll give up its heat to the inside of the house,” he said.

The reverse effect can be used in the summer by running cool liquid through the tubes.

A synthetic stone cladding incorporating concrete will be used on the exterior of Pensmore, Huff said.

“Concrete is quite a specialized method of construction, especially if you want it to be exposed concrete,” said Ati Blackwell at Marlon Blackwell Architect in Fayetteville.

She said an addition the firm is building next to Vol Walker Hall at the University of Arkansas in Fayetteville is being made mostly with concrete.

“It can be truly beautiful if it’s done right ... but it’s a specialized technique,” Blackwell said.

Collins Haynes, a Rogers architect and developer, agreed.

“The real issue in this concrete is finding and using someone who knows what he is doing, and having a very reliable source for the concrete,” said Haynes. “Material, experience and money are the keys.”

Northwest Arkansas, Pages 17 on 10/23/2011

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