A rectangular structure is built of walls, which are vertical, and a roof. The roof acts as an umbrella, keeping most (not wind-blown) moisture off the walls, windows and doors. A dome is all roof; water, including mists or fog, pours over the entire surface. Unless the dome is covered with shingles, the slightest pinhole causes leakage.
Rectangular buildings are shaped by available materials — wood, stone, adobe, etc. — and the laws of gravity. Domes are shaped by polyhedral geometry and materials must be forced to carry out the abstract concept.
The dome framework, due to its tightness, is continually under stress. As temperatures change it expands and contracts. It is always working, always straining at the seams.
Domes must be built of higher grade materials. The kiln-dried lumber required for framing is over twice as expensive as construction grade lumber used in stud framing. See cost comparison below.
Almost all building materials come in rectangular shapes. They must be altered to fit polyhedral shapes, either with resultant waste or more complicated cuts.Also, once materials are cut for dome assembly they are-difficult to recycle in another building.
A far greater variety of materials can be used in conventional construction: rock, adobe, used wood, doors and windows, construction grade lumber, etc.
An important feature of an owner-built home is the possibility for later expansion. With a perpendicular wall, you merely add on more roof and walls, all at 90°. With a.dome, however, you weaken the structure by cutting into it and must cut compound angles and tie into multiple facets when adding on.
Similarly, constructing interior partitions in a dome is far more time-consuming, due to the compound angles.
The dome’s well-publicized “more space for less materials” actually means more cubic area (overhead) that is hard to utilize and must be heated.
We are vertical to the earth. So are refrigerators, beds, bureaus, tables, kitchen counters, etc. These things fit best in a rectangular space, less efficiently in circular space.
Each triangular facet of a dome faces center; this magnifies noise. Also, smells circulate throughout the entire dome.