Most Frequently Asked Question:
Can You Build These in the US?
by Rebecca South
June 16, 2004
Answer: Of Course! But NOT for housing.
I get a phone call at least once a day about building EcoShells in the US or Canada for housing, either for a private home or for a small development. I understand that we are all looking for the best home for the least amount of money, but in the US and Canada, the EcoShell is NOT the answer.
The main reason for this is that EcoShells are uninsulated. The temperature swings in the US and Canada are too great, and our demands are too high on our HVAC systems for an uninsulated building to be appropriate.
Now, if your alternative is no better than a metal tent, than the EcoShell would be better, but I think there would be issues with codes.
The EcoShell works as practical housing only in equatorial climates where the temperature fluctuates from very hot to hot. In less developed countries where cheap, permanent structures are greatly needed, EcoShells often can fill the bill.
2nd Most Frequently Asked Question:
Why Not Just Insulate the EcoShell With Something?
When a person gets to this question, which always follows the first, then I have to say the only answer is the Monolithic Dome.
A Monolithic Dome starts with an Airform that remains on its outside, acts as a single-ply roof membrane, and is the dome's first line of defense against leaks. Next, polyurethane foam is sprayed then rebar is hung and shotcrete is applied-- all from the inside. This is the best way to build an insulated thin-shell concrete dome. Period.
At this point this article could get very long... usually a lot of ideas are tossed around regarding cheaper ways to insulate a thin-shell dome. The one thing I'd like to impress on anyone reading this is that I can almost guarantee that the Monolithic Dome Institute has tried it.
Many potential customers want to peel off the Airform and re-use it. That is what they started out doing. And they learned that you will spend more money removing, repairing, and recoating than you will if you leave the Airform in place. Once off, it must be replaced by a coating of equal value. But there are no coatings that are as strong, tough and permanent.
As with the Airform, there is no substitute for urethane foam insulation. The use of any other material will not produce as good results. Urethane on the outside of the concrete allows the concrete to store an enormous amount of heat very effectively. This thermal fly wheel effect added to the urethane's superior insulation is why heating and cooling loads are so vastly reduced in Monolithic Domes.
Many still want to skip some of the Monolithic process and still derive the same benefits. People have tried to build an EcoShell, spray the outside with urethane foam insulation, then coat over the urethane. In general such an EcoShell appears to be the same structure as a Monolithic Dome -- but not really. Its construction is more difficult, it will never be as well controlled, or as well constructed and it will cost at least as much money -- if not more.
There are people building EcoShells, covering them with straw bales and then building another EcoShell over the outside of the first. This can be done. It is doubtful that it will save money, and there are problems with the details for doors and windows. Lastly, if it isn't done just perfectly, it will leak when completed. But it will be energy efficient as long as the straw lasts and that may be a long, long time.
Monolithic suggests that If the cost of a new home is too high, make it smaller. But in the final analysis, each client has the option to build whatever he or she wants.
I am not so sure of everything not to believe there may be the perfect answer still out there, but I do suggest everyone a little research on the Monolithic website and ask the builders on the Monolithic Bulletin Board what they've tried. They are currently doing experiments with re-claimed foam and dehydrated styrofoam beads. As for me, I'll wait to see what they come up with before I spend any money on something unproven.