Berming a Monolithic Dome
Berming or partially burying a Monolithic Dome for design reasons is fairly common. A few people have built their homes “into” a hillside for a natural effect (See The Invisible Dome Home, and Robot Ranch). Some berm around the dome to echo the architectural curves of the structure. Others may use berming strictly for landscaping purposes. And there are those who may like the extra privacy.
Whatever the reason for berming your Monolithic Dome, you’re in luck! It’s very simple to do, because of the Monolithic Dome’s inherent strength (See Building Survivability). It is possible to berm one-fourth to one-third of a Monolithic Dome without additional engineering. However, if the plan is to berm more than that, or to actually bury the building, you must check with an engineer for further instructions. (Read more about Understanding the Ups and Downs of Building Underground and Underground Air Piping.)
How to Berm:
Even though water won’t go through the Monolithic Dome shell, it can follow the shell down to the footing where it can seep under the footing and come up under the floor. To avoid this problem, the footing must be drained. This can be done by putting a drain under the floor around the building. It should be drained to a lower elevation if possible. If draining to a lower level is not possible, then a french drain or sump must be built.
The preferred method for backfilling is to use a skim layer (4" to 12") of pea rock against the Airform to the footing. This forms a filter for water to flow down the building and through the footing’s drain. NOTE: There is a danger of the filter filling with dirt and malfunctioning. There are fabrics that can be used as a filter channel as a substitute for the pea rock.
A clay or impervious dirt should be used at the top of the berm to force surface water to drain away from the building rather than go down through the filter.
Note: Be sure to understand the insulation implications. See R Fairy Tale.