straw bales

Hi,

I would like to know if there are any "green builders" in my area.
I'm interested in the straw bale homes.

Thanks,
Judy
Albuquerque, NM

The very thick walls of straw-bale houses (also rammed earth, double-thickness adobe, etc.) need an equally wide foundation (18-24 inches or more) to support them. In mild climate with sandy soil this is not a big problem, as the concrete foundation can be modest in depth (1-2 feet). But where deep frost-heaving or expansile soils are present (much of the country) you may require foundation depth of 4 feet or more. Making a 2 ft wide and 4 ft deep foundation takes a hell of a lot of concrete and rebar.

I have 2 ideas to reduce the materials required in such conditions. One is to engineer your foundation in the shape of an I-beam instead of a solid rectangular block. The I-beam principle is widely used in steel, engineered wood, and reinforced concrete to maximize strength while minimizing weight and material (hence cost as well).

--see cross section drawing below -- At the bottom of the foundation you'd have a 1 ft high by 2 ft wide base, then a web 8-10" thick by 3 ft high, then another 1 ft by 2 ft section sitting on top of the web -- total height of your reinforced concrete I-beam ~5 ft.. You would undoubtedly need an engineer to certify this design, but it would be easy to build and save a lot of cement and iron.

The second scheme I've thought of could be substantially cheaper and even "greener" -- an old idea but seldom used, why I don't know -- the grade-beam foundation. I associate this idea with FL Wright, but he may not have invented it. You excavate a trench to required frost-stable depth, say 5 ft deep by 2 ft wide, fill the trench with rocks to approximately grade level. Then build your foundation form, say 14" deep by 24" wide, directly on top of the rock base. On the rock base, Wright even used heavy wood timbers fastened together, instead of concrete, for some of his foundations; and if you had a bunch of used railroad ties or creosoted bridge timbers you could easily concoct some mixed-media foundation, sandwiching the timbers and reinforced concrete, using the timbers on the outside as "form," reinforced concrete in the middle, all tied together with rebar and reinforcing mesh.

Robert B. wrote in with this question:

I was planning to build a steel barn/workshop (abt 2000 sq ft) to live in while I built my real home on my property. But your show gave me the idea that I might be able to build a straw bail barn/temporary home more cheaply and "greener." Is there any reason I could not do that?

If not, where might I find some plans and other materials on how to get started?

This good question comes from Sandra B.: 

Strawbale building: I bought a lake house on a slab & pier and beam. Is it possible to build strawbale on pier and beam. If yes then what supports the bales?

 We've got four questions here form Kevin B.:

I have been watching your show since it first starting airing here in the Kansas City area.  Great information, and very educational/entertaining.

My questions for you are:

1: Is it possible to apply a stone/brick veneer over the outside/inside of the structure?  

2: My nephew in law lives in the Denver area and works for a contractor who is using a recycled block made from shredded railroad ties and some sort of polymer for foundations.  Have you heard about this product, and if so, how do you think it would work above grade?  

3: You said that straw bale construction is not advisable in high
humidity areas, could you elaborate on this, a bit?  Today my humidity
here is at 67%, and 100% is not unusual in the summer.  

4:  Which type of solar hot water heater is the best?  I am thinking of building an earth contact greenhouse and using solar heated hot water radiant heating, with a wood pellet fired boiler as a backup/supplemental heat source.
    

Thanks for your time and consideration.

John from Hawaii sent us some good straw bale questions:

I’m new to this topic and find the idea of using straw bales to build homes so logical that it makes me wonder why it isn’t more popular! I have a few questions for you:

1. Are there any problems with straw bale construction in high humidity climates like Hawaii?
2. Can straw bale homes be made to withstand hurricanes?
3. Do termites pose any kind of threat to straw bale construction?

Mahalo,

John

Ultimate Home Design magazine did a wonderful write-up of a project our company, Mountain View Construction, recently completed in Central California. With permission from the author, Paula Aiton, we're republishing it here so it will be accessible online. Enjoy!

Straw Bale Construction in Central California
By Paula Aiton

Reprinted from Ultimate Home Design

For homeowners Ira and Brady Rubin, building an energy-efficient home in Visalia, California had long been a dream for the couple and their family. Now a reality, the 3500 square foot home, built using straw bale wall construction, sits on five acres of land just outside of town with a sweeping view of the nearby Sierra Nevada Mountains. In an area of Central California where agriculture is the primary industry, and the idea of hay or straw might be more vividly associated with livestock, this type of construction is becoming more and more popular as a means to achieve many goals, not the least of which is energy efficiency and fire protection.

For many years, the Rubin’s grown daughter, Daryn, had been reminding them, "There is only one issue: the environment!" When she and her husband, John, invited the Rubin’s to create a family home with them and their small children, the entire family embraced the concept of building a sustainable home. They considered a variety of sustainable materials: SIP panels, rammed earth, adobe and even discarded tires. In 2005, they participated in a straw bale workshop with the company, Real Goods, in which they built a small kiosk for a river-rafting company. After that experience they were "sold on straw bale," Mr. Rubin said.

click the link below to read more...