Level Land

Establish a level and clear area for the dome. Sandy soil, rather than rocky is best as rocky substrate will transmit ground-shock more intensely. (For my office-dome, I removed some of the hard-pan and brought in a fine sand to put under the foundation so it could absorb shock better than the hardpan. There is building literature pertaining to these principles.) Drive a stake at the center point and attach a non-stretching line to a nail in the top of the stake. The line will have another scouring pin or stake at the free end, with the length of the line being equal to the desired radius of the dome.

Beginning at a point at the length of the line (the radius) from the central stake, scratch or scour a line around the full circle the full distance from the center stake. When you are done at this point, you will have a center stake with a circle around it demarking the perimeter of the dome. Since lines in the sand are unstable, drive vertical stakes in the ground, perhaps 18'' apart, to a uniform height equal to the desired height of the monolithic slab you will pour (at least 4" to 6"). These stakes need to be strong and deep, as they will brace the concrete form, and they need to be at the same level.