Foundation walls built with concrete block offer an economical alternative to poured concrete and have many of the same strength and load-bearing characteristics. Held together with mortar, concrete-block walls must rest on a level, solid footing. Reinforcing bars (rebar) are inserted vertically through the blocks’ hollow cores, which are then filled with concrete; this increase resistance to wind and soil shifting. Some of the newest block systems have built-in compartments for foam insulation, making them highly effective insulators.

   Many builders prefer to construct traditional strip foundations from poured concrete. They’re strong and familiar to subcontractors, and the process is faster than laying up block.

   Although a poured-concrete foundation may look invulnerable, it’s more like a very dense sponge that must be protected with water barriers and proper drainage. Refer to the inspection checklist as workers remove foundation forms and prepare to backfill. Make certain that drainage, termite control, water protection and insulation needs have been addressed. In some regions provisions should be made to dissipate radon gas emitted from subsurface rock.