The whole issue of transportable concrete domes is intrigueing and difficult at best. Thin shelled concrete domes are incredibly strong yet incredibly heavy when compared to most standard building materials. I recieve a lot of inquiry from various places in the country about the transportables, especially 2 piece units that are up to 30 foot in diameter.
Dome halves to be shipped that are wider than 12 feet require escort vehicles, not to mention the assembling and sealing of the units together. This all becomes prohibitive for cost when shipping these structures very far. The other consideration is that smaller domes utilizing stem walls have a greater surface area of shell to floor ratio. The smaller the dome or barrell vault, the more it will cost per square foot for this reason alone. Add to this the added cost of efficiency loss due to building smaller structures and you end up with a greatly increased construction cost.
A 12 X 24 foot barrel vault with a 5 foot stem wall has the following surface areas:
Shell surface area: 680 sq. ft.
Floor square footage: 257
Shell to floor ratio:2.65/1
A 30 foot diameter eliptical dome with no stem wall has the following surface areas:
Shell surface area:1151 sq. ft.
Floor square footage: 706
Shell to floor ratio: 1.63
It's better to build a dome with no stem wall if you are concerned about cost. You will pay not only less for the shell, but you will be spreading out the cost of the kitchen, bathroom, etc over more square feet of total living space, because it will be a dome of more floor area.
Something small only works if you cannot build in place or it must be moved. You must not care about paying a premium price to have these features. You will also have more advantages in strength and design by builing in place.
We currently have a 12' X 24' unit for sale
Owner had a change of plans and is wanting to sell his 12' X 24' barrell vault unit. It is 257 square feet, with a bathroom and kitchenette. It is wired for 100 amp service with a 9000 btu air to air heat pump which operates down to 5 degrees farenheight. It is identical to the unit shown above in the slide show.
A full bathroom with shower, sink and toilet
A kitchenette with electric stove and regridgeratore
Molded foam overhangs
Ceramic tile floor
Foam insulated floor
It is ready to hook up to water, sewer, and electric and it is ready to live in. Makes a very nice cabin. Insulated with 3.5 inches of roof density urethane foam insulation Exterior is urethane rubber with light weight aggregate for texture. Designed to set on a concrete foundtion.
Please contact us for more information.