Archive for Sunday, July 30, 2006

Concrete results: New house’s efficiency is a stunning surprise for builder, who predicts 75 percent decrease in utility expenses

The right idea at the right time?

July 30, 2006


John Craft, owner of Kaw Valley Home Care, stops along the stairway of one of his recently built homes at 1417 Prospect Ave. Craft believes that the home is the most energy efficient in the area, primarily because of its use of concrete walls and floors, which keep the interior at a near constant temperature.

John Craft, owner of Kaw Valley Home Care, stops along the stairway of one of his recently built homes at 1417 Prospect Ave. Craft believes that the home is the most energy efficient in the area, primarily because of its use of concrete walls and floors, which keep the interior at a near constant temperature.

John Craft was mad when he walked into the new East Lawrence home he was building.

He'd been gone about a week, and when he walked in from the 100 degree heat, he was greeted by a cool 78 degrees. He was upset his workers had left the air conditioner on.

Then he realized: They hadn't.

Despite a week of triple-digit temperatures, the temperature in the home remained below 80 degrees.

"I think you may be looking at the most energy-efficient home, maybe in the state, but I'm pretty sure in the area," said Craft, owner of Kaw Valley Home Care.

Cooling concrete

That's not by accident. The home at 1417 Prospect Ave. is unusual. For starters, its walls are concrete - eight inches of cement sandwiching four inches of Styrofoam.

And the floors in the house - up and downstairs - are concrete. That allowed Craft to heat the home entirely with radiant heat, a system of tubes piping hot water through the concrete floors. Instead of a traditional furnace, the house is heated with a 50-gallon, high-efficiency water heater.

Craft predicts utility bills will be about 75 percent less in this home than in a traditional house, though he won't know for a while because construction was just completed.

"I think most of the time, the utility bill will just be the minimum charge that the utility companies make you pay," Craft said.

The key to it all, Craft said, is the concrete.

"There's so much concrete in here that it keeps the house at a nearly constant temperature," Craft said of the 1,500-square-foot home. "Basically, once you get the concrete at the temperature you want it, it stays that way for a long time."

But do people really want to live in a house with so much concrete? Craft is betting some do. He built the house on speculation, meaning he built it without a buyer. He just finished the home this week and plans to put it on the market for a little less than $200,000.

With soaring energy costs, builder John Craft thinks houses like this 1,500-square-foot one at 1417 Prospect Ave. may be the wave of the future. He plans to put it on the market for a little less than $200,000.

With soaring energy costs, builder John Craft thinks houses like this 1,500-square-foot one at 1417 Prospect Ave. may be the wave of the future. He plans to put it on the market for a little less than $200,000.

He's already planning on building more of the homes, and he thinks concrete housing will become more popular across the country.

"I absolutely think people will start building homes more like this because the public will start demanding it," Craft said. "Maybe utility prices aren't high enough now to spur it, but just wait a year or two and I bet they will be."

Cusp of change?

But new neighborhoods of concrete homes probably won't happen anytime soon, according to Shery Hoellwarth, a consultant with Stockton, Calif.-based ConSol. The company provides technical assistance to builders wanting to construct homes with an eye toward energy efficiency.

"It is a slow industry to change," Hoellwarth said.

Builders prefer to do what they're comfortable with, and they haven't had much reason to change.

The home is heated by hot water tubes running through the floors and controlled by this high-efficiency water heater.

The home is heated by hot water tubes running through the floors and controlled by this high-efficiency water heater.

"Up until now, builders have been able to sell pretty much everything they're building, so there hasn't been anything pushing them to change," said George James, project leader of Building America, a Department of Energy program that partners with home builders to promote energy efficiency.

But times and attitudes may be changing. James said the National Association of Home Builders has been preaching energy efficiency to its members, and there is a different breed of home buyer slowly emerging.

"A lot of the younger folks are very interested in green energy and sustainable practices," James said. "My hope is that in 10 years the building industry is substantially different. But what's more important than my hope is that I'm starting to see some signs of that."

Craft is even more confident. A combination of warmer temperatures, higher utility prices and the role oil is playing in world politics has him convinced more and more people are ready for a different type of home.

"I have to say that I have a problem with us being in a war that I think is pretty much about petroleum," Craft said. "It just seemed to me that this was a good time to build this home because with what I see in the world, I don't think petroleum or energy prices are ever going to go down.

"I'm really excited about what we're doing because it seems to be the right idea at the right time."

Tips for building an efficient home

George James, of the Department of Energy, said concrete is a good way to build an energy-efficient home. But there are other ways, too. Some examples: ¢ Metal roofs. John Craft used a white metal roof that reflects the hot summer sun. ¢ Lots of southern facing windows. These allow sun during the winter to shine into the home and provide natural warmth. Craft said this is particularly useful when combined with heat-absorbing concrete floors. ¢ Window awnings or overhangs. The overhangs protect the southern-facing windows, and others, from summer sun. ¢ Thicker walls. You don't have to use concrete to beef a home's walls. Builders can use 2 by 6 lumber to frame walls rather than the traditional 2 by 4. This provides more room for insulation. James thinks this will be one of the more popular trends in building because contractors are discovering they can safely use fewer pieces of the wider lumber to support the home, thus saving on lumber bills. ¢ Tighter duct work. Shery Hoellwarth, a consultant with Stockton, Calif.-based ConSol, said making sure duct work is tightly sealed is one of the easiest improvements a builder can make. "Most people have no idea how much air conditioning is going up into the attic where they don't care whether it is cool," said Hoellwarth, whose company helps builders construct energy-efficient homes. ¢ Better quality windows, doors and appliances. The federal governments sponsors a Web site - - designed to help consumers select energy-efficient appliances and materials.

$avings within sight

Through the Department of Energy program he oversees, George James has watched Habitat for Humanity build homes that cost their owners only 23 cents per day in utility bills. But each of the homes was equipped with $25,000 worth of special solar panel cells, a financially unfeasible alternative for most people. Eventually, though, the price of solar panels - like all technology - likely will come down, and James' Building America project is researching other energy-saving possibilities all the time. "The goal is that by 2015 we'll have solid research done that shows people how to design a house to save 40 to 60 percent of its energy without adding much cost to construction," James said. Lawrence builder John Craft, who this week completed a new concrete home, also is optimistic. He estimated the 1,500-square-foot home cost him 20 percent more to build than if he had used traditional methods. But once he becomes more familiar with the building process, he expects the cost difference to drop to about 10 percent. He thinks that price difference will be worth it for owners wanting a more efficient and durable home. "This concrete, because it is stained, never has to be painted, and you never have to worry about termites," Craft said. Concrete may not be right for everyone. For example, Craft uses concrete on the interior of the house, too, meaning walls don't have that traditional drywall look. Also, since the home uses concrete flooring with radiant heat, wall-to-wall carpet may not be the most practical.


1lawrencemom 11 years, 7 months ago

$200,000 at 15th and Prospect? Good luck with that!

redearthchild 11 years, 7 months ago

How is the house ventilated? If not well ventilated, might indoor air toxin levels increase with the increasing efficiency?

kingdork44 11 years, 7 months ago

What ever happened to the Earthbearm homes. Isn't this the same Idea?

just_another_bozo_on_this_bus 11 years, 7 months ago

If the tubes were installed correctly, they should last for decades.

Janet Lowther 11 years, 7 months ago

PS: On the efficiency front, I'd be interested in seeing how it compares to my ex-in-laws superinsulated place near Keats: They have 6" of styrofoam + 3.5" of fiberglass in the walls and 30" of rock wool in the attic. IIRC the floor & the bottom four or five feet of the back wall are concrete.

southerngirl 11 years, 7 months ago

I saw the picture, but when I think of concrete homes, I think of Fred Flinstone's house...


kingdork44 11 years, 7 months ago

Yes, I do see your point "just_another_bozo_on_this_bus" And you don't want to do this if you live near a Gas Station!

just_another_bozo_on_this_bus 11 years, 7 months ago

Some similarities, but it's not always possible to bury the north wall of a house on a small city lot-- not to mention that anything underground creates drainage issues that need to be carefully dealt with.

javery 11 years, 7 months ago

I spent a number of years living in the Caribbean (my parents still live there) and all of the houses there are built of concrete. It has perplexed me why people here in the midwest don't also build homes with concrete, as they are so much stronger and could probably withstand up to an F-3 tornado, unlike wooden houses. Anyway, some people have asked about how you hang pictures. Just use masonry nails.

just_another_bozo_on_this_bus 11 years, 7 months ago

You can get similar effects to concrete floors with various earthen mixtures that can be sealed with a variety of products, and they are much easier to walk on than concrete. Materials are a lot cheaper, and you can do the work yourself, although it's not an easy job.

Sandra Willis 11 years, 7 months ago

Old Enuf, The 50+ year-old home that my husband and I bought 10 years ago has moved quite a bit ... Before the city dealt with the fact that the yearly spring rains needed to be dealt with we had streams of water flowing UP our driveway, through the garage and into the back yard. We tell people that we have a yearly swamp in our back yard. Bodan

Confrontation 11 years, 7 months ago

They've been building only concrete houses in certain parts of Africa since this technique became available. This is especially true for coastal cities. These homes last a long time and there's no wood rot. It just doesn't make sense to build a house that can be eaten by bugs or flattened in high winds. I would love to have a concrete house.

Sigmund 11 years, 7 months ago

Radiant heat is wonderfully good, but initially expensive to install. Concrete sounds like an excellent building material as well. If I were looking for a home I would definately consider these materials and technologies.

But can that neighborhood support a $200,000 home? I am not sure I would ever be able to get that out of it if I decided to move. Thoughts?

Shawna Huffman 11 years, 7 months ago

I love my concrete house! My energy bills are very reasonable. If we move to another home, it will also be built using the ICF method (Styrofoam & concrete). I recommend this building method for anyone looking to build. It also comes at a reasonable building cost, so why not use this construction method?

Jersey_Girl 11 years, 7 months ago

A friend of mine has a concrete house and it really is amazing. I don't know how she hangs pics, but she does. I'm less concerned with picture hanging (I'm sure it can be accomodated somehow), but how does it withstand tornados? It would seem to me you would be extremely safe in such a house, no matter what the weather. You might have a few broken windows, but the house its self would stiil be standing.

Janet Lowther 11 years, 7 months ago

Concrete houses have the POTENTIAL of being much more structurally sound than conventional frame houses: When I was a kid, we went to look at the damage from the great Topeka tornado. At one point there was a lone house standing in the midst of devastation. Its windows were out, but it was in otherwise good shape. I subsequently found out that it had been built of reinforced concrete.

If a concrete structure is built with the floors, walls and roof structure tied together with steel reinforcing, the entire structure will tend to move as a unit: It may get out of plumb, but is unlikely to crack, floating on the soil like a concrete boat. (Yes they do make boats and barges out of concrete. They call the technique "Ferro-cement.")

badger 11 years, 7 months ago

I don't know about concrete houses, but since moving south I've become enamored of stained concrete flooring. It does keep a room cooler than either carpet or tile, and some of the designs are remarkable. It's fairly cheap and relatively simple to do.

The dorm I lived in in college had cinderblock walls. You hang pictures with anchors specifically designed for hanging in harder substances with less give.

Then, apparently, when you move out you fill the drill-holes with toothpaste so the mint oil can leave big discolored spots on the wall, and the room can be minty-fresh for its next occupant.

I imagine, though, that if you had a concrete house you wouldn't have to do the bit about the toothpaste.

OldEnuf2BYurDad 11 years, 7 months ago

"If the tubes were installed correctly, they should last for decades."

I'd prefer more security than this. I mean, if they are NOT well installed, and if the ground moves under a slab house, then it seems logical that a homeowner could be looking at MAJOR repairs.

In this heat we've had, I've had to take tools to my front door striker plate to get the door to lock due to the movement of the soil. On the south side of my porch, there is a gap between the house and the concrete porch that is over an inch wide. Logically, since most slab houses eventually develop some cracks, this approach carries a lot of risk.

My house is 50 years old. How many years do slab houses go before they begin to produce cracks, on average? This would be my fear.

just_another_bozo_on_this_bus 11 years, 7 months ago

This house is slightly different from most foam/concrete combinations. There are two 4" thick concrete walls encasing 4" of foam insulation. Most of the other types use EPS forms and the concrete is on the inside. Those systems mean that both the inside and outside need to be finished with siding and drywall. The walls of Craft's house are already "finished" with concrete.

While this house will be worth the premium price in the long-run, all concrete and foam structures have the disadvantage of a high level of what is called of embodied energy use. That's because the production of both materials requires a large amount of energy. As the cost of energy rises, the cost of construction of this type of structure will rise, too, but it's low-energy usage once it's built and low-maintenance costs will balance that out to some extent, so it will remain competitive with traditional stick-built houses, which are very energy inefficient to build, too.

Shawna Huffman 11 years, 7 months ago

My home, as mentioned in the first post, is built with styrofoam on the outside and concrete poured down the middle. I believe that there is also rebar in the middle with the concrete. The styrofoam layers are connected, sort of like a hollow block, and are stacked on top of each to acheive the desired height/design. Then the concrete truck comes in to pour the concrete.

As for the finish, my interior walls have all the electrical, plumbing, cable. etc. that are normally found, but those trades used a chainsaw of sorts to create a channel in the styrofoam for those wires to 'run' in. Drywall is attached to the styrofoam and painted like any other house. I used picture hangers (nail with that hook thing) for alll my pictures, we used drywall anchors for anything requiring a screw.

As for my exterior walls, the builder used a concrete & recycled #1 plastic mixture for the siding. Stucco is also commonly used. Our house looks very normal.

My home is very sound proof, I live very close to the train tracks and we only hear them when in front of a window on the north side of our house. Our small children hardly notice them and aren't wakened by them in the night. :)

I'm told our house can withstand a direct hit from a F4 tornado and still be standing. I think the roof will rip off, but some hurricane rated roof anchors would probably fix that issue.

Kathleen Christian 11 years, 7 months ago

NAHB - National Association of Home Builders in Bowie, MD have been building energy efficient homes like this for years. They build 3-4 test homes and eventually sold them. I remember one was made out of recycled trash from a dump, along with concrete, foam and other energy efficient materials. Was a beautiful home too. I was surprised when I moved to the mid-west to discover how cheaply made new are are built in this town. Ryan homes are the worse. They were cited in Maryland for using cheap wood. They were made to replace ALL the roofing plywood on all the townhomes where I was living because they did not put in fire retardent plywood which is required for all new homes in Maryland. Homes are built better there because of the more stringent building codes. Probably why Ryan came out here to build - they could get away with using cheap materials. However, there is an apartment complex in MD built of concrete with concrete floors - where you CANNOT hear your neighbors walking, TV or music. ALso, this technic isn't all together new. Eleanor Roosevelt supported having housing built for military families back in the day and these first apartments were built using concrete and brick. These apartments in Greenbelt, MD are still standing today and being lived in.
I think it's a wonderful idea as long as homes are sold at a reasonable price and the builders don't become greedy like most do and charge outrageous prices. I know I'll never be able to buy a home - I'll be renting for the rest of my life.

Concrete_home_pro 11 years, 7 months ago

I work for the Portland Cement Association, and run the Concrete Homes website. A lot of the questions everyone has asked are very common when it comes to concrete homes. I can address those that are posted here, and will also provide my e-mail address at the end of this post for any additional questions.

In an ICF home, you hang pictures almost the same way as a stick-frame home. There are plastic or metal ties in the ICF system that are used for 3 reasons, and one of them is interior and exterior attachment points. You simply use a screw or nail to hang your pictures on. That's the quick answer. I can supply a further detailed answer if necessary.

Concrete homes stand up to natural disasters very well. Hurricanes, tornadoes, earthquakes, wind, even cars and explosives. I have information on all these for anyone interested.

Utility bills are drastically cut. Two quick examples: A 3,000 sq. ft. home in TX with a monthly utility bill under $100. A 2,700 sq. ft., with full basement underneath, in southern MO that never paid more than $28 a month to heat and cool their home.

Indoor air quality is better than a stick-frame home, because of the decreased air infiltration (through the walls). It's an easier environment to regulate. That's why a few wine afficianados in CA have built wine cellars out of ICFs. They can control both temperature and humidity to the degree and %, respectively.

Embodied energy accounts for about 2% of the total energy usage of a structure over it's lifetime. While concrete homes do have more than stick-frame, the energy usage over the life of the structure easily offsets the initial increase.

My e-mail address is if you have any other questions.

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