Off the keyboard of Eddie
Published on SUN4Living on April 8, 2014
Discuss this article at the SUN Table inside the Diner
Today was our first day of what looks to be five pretty full days here at Monolithic Domes. Today we heard from a couple of speakers, including Monolithic’s founder and CEO, David South. It was probably worth the price of admission to listen to David, who is one of those visionary geniuses who has managed to combine his passion with a business that builds exactly the kind of structures that he once dreamed of.
Regardless of whether I ever build a single dome, it’s been good to meet and pick the brain of someone like this guy. He is way ahead of us Diners in many ways, not only having already figured out how to build these extremely functional buildings of his, but also how they can fit into the paradigm of energy descent as affordable housing for working poor people and retirees with limited means.
He actually already has a community of tiny rental domes here on the company land (where many of his family members and employees also have dome homes), as well as a couple of others in nearby towns. It is a working, functional model that does not depend on government assistance. They operate as residence inns that rent (currently for $125 per week). It’s an interesting model to me, because it seems like one of the only landlord/tenant arrangements I’ve ever seen that works out to a win/win for both owner and tenants.
Another vision at Monolithic is their Grow Domes, which allow intensive indoor gardening indoors, requiring minimal energy inputs.
It makes me dream of an affordable community of tiny domes and dome fourplexes with access to onsite grow domes where residents can grow their own food in an environment protected from the vicissitudes of climate change. In my view, such a community would have the potential to free people up from the hamster wheel of low wage work and allow them to live with a great deal more resilience and dignity.
The only thing I’ve seen that I can criticize is that domes are constructed using a lot of closed cell polyurethane foam, which requires specialized equipment and chemicals that are noxious during construction, although it appears to be safe enough after it dries and is covered with sprayed on concrete plaster. Of all the building designs I’ve studied, only the Global Earthship rivals the Monolithic dome as a dwelling.
Monolithic Dome Training, day two: Everything You Always Wanted to Know About Rebar, But Were Afraid to Ask
Monolithic Dome Training, Day 2
Today we began the morning by hanging rebar in a small dome being constructed on the sprawling premises of Monolithic. (They occupy about twenty acres of prime freeway frontage on Highway IH35 just south of Waxahachie, in Italy, Texas, adjacent to one of the ubiquitous rural cotton fields that surround suburban Dallas.)
We then got an intensive classroom lecture on the subject later in the morning, followed by an afternoon split session, during which most of the attendees went out to shoot shotcrete after lunch. David South remained in the lecture hall, and Haniel and I took advantage of the time to talk to him at length about our perspective on energy descent and collapse, and discuss our tentative plans, hopes and dreams. He encouraged me to write an article about my PV Kit and for Haniel to write about his plans for building dome villages for Boomer retirees, which he offered to publish in his monthly newsletter, which goes out to some 20,000 subscribers. Very cool. I hope we can take advantage of his offer.
Perhaps it would be good to describe how a Monolithic Dome is constructed.
It begins, like most buildings, with a concrete slab, in this case round. A footing is poured in the circumference of a circle. The footing is a deeper ring of concrete around the outside edge of the circle that give the building its supporting foundation. The rest of the slab is not as structurally important, but it is usually contiguous with the footing and forms the floor of the building.
The next step is where the innovative stuff comes in. A pre-fabricated fabric bag is stretched over the edge of the footing and anchored in place. A special inflater is attached and the bag is blown up, making a ballon scaffolding on which the building is constructed. After the building is completed, the bag remains as a plastic skin. (After some years it degrades and the surface is re-coated, usually with sprayed on concrete.)
After coating the interior of the inflated bag with a primer, it is then coated with a layer of closed cell urethane foam. Then special rebar hangers are embedded in the dry foam wall, and a second layer of foam is added to lock in the hangers and bring the foam layer to three inches of thickness, which will make the completed dome a super-insulated structure.
Then a rebar cage is constructed on the inner surface of the foam, with a 5/8 inch stand-off to allow the next layer, which is sprayed concrete, to completely embed the steel and form the load bearing dome walls and ceiling. This layer is 3 to 4 inches thick. This kind of construction is referred to as “thin shell construction” and requires perhaps half as much concrete as a conventional concrete building, but is in fact structurally much stronger due to the inherent strength of the dome shape. Strong enough to withstand hurricanes, and tornadoes. The concrete inner wall also give the building a lot thermal mass.
So that is the basic building method. Many dome builders modify these techniques and try various ways to cut costs or improve on Monolithic’s techniques, and I found it extremely useful to discuss various bits of dome building lore I’d read and heard about with David South, who has built literally thousands of these structures. He is a very knowledgable man who has had many successes, but also has had the benefits of a few failures, and has tried and abandoned many of the alternative ideas I’d heard about, such as using fibers to reinforce the concrete instead of steel rebar.
Although South freely admits that small domes might be reasonably strong without rebar, he says that rebar gives the dome the ability to withstand unusual forces, such as extreme weather events, earthquakes, and soil subsidence. He is a staunch defender of steel reinforcement. Part of his motivation is to create buildings that can last for hundreds of years. Since they can be built in the same cost range as stick built houses, but last much longer, they have exceptional value for the price.
There is one extremely exciting new development in concrete construction, and that is the use of basalt rebar, which is stronger than steel and made from naturally occurring volcanic rock which is found in many places in the world. It is also impervious to rust, which can be a problems with concrete that is exposed to the elements. Monolithic is using basalt rebar in many of their builds now.
It’s been a long day for the Diners. More tomorrow.