The following photo is of a 1260 square foot earth contact, light weight concrete gunited free form open faced dome. My entire owner built complete cost was approximately $26,000. The design requires some familiarity with concrete work and therefore may not be suitable for all owner builders. (updated 7 Dec 98)
Note: To prevent any nonuniform settlement of the dome, the beam footing was heavily reinforced and kept to a 10" width. The standard codes call for wider footings, but then again, at least 80% of houses built under standard codes, have foundation cracks. With a concrete roof, it is not advisable to follow a tradition that could lead to cracking and subsequent roof leaks. With a narrow footing, there will be greater soil pressures, leading to a possible increased settlement, but settlement is not a problem, uneven settlement is.
