Making the earth-sheltered building secure from water infiltration is more essential than it is for above-ground buildings because repairs, if needed, are much harder to make. Measures for watertightness must be well planned. Following are suggestions that can stop problems before they begin: Obtain the assistance of a designer and engineer familiar with the area where construction will be done; avoid building in any location with a high water table; bore to determine the soil conditions before building; design for control of surface water; provide for proper excavation and backfill; provide proper and adequate waterproofing of walls, roof and floor; and relieve water pressure against the outside wall.
RELIEVING WATER PRESSURE AGAINST OUTSIDE WALL
Place drain tile around the outside of footings, keeping the top of the tile below the tops of the footings. (Concrete drain tile should be laid with their joints covered with building paper, and then backfilled with stones or a filter-grade sand.) Consider using drain tile inside the footings also, with large-radius corners and openings for cleanout. Additional drainage can be installed at upper levels if necessary.
JOINTING THE CONCRETE
The reinforcing steel in the concrete will stabilize any fine hairline cracking. Steel, however, cannot be expected to prevent a few wider vertical cracks that may develop from drying shrinkage of the concrete but these can be accommodated by control joints. Control joints should be located about 15 feet apart. Their purpose is not only to cause any cracking to occur in predetermined locations but to provide a resilient barrier that will seal out water. There are three types of barriers: the joint sealant, the waterstop, and the preformed compression seal.