A couple of things that Lifestyle Homes does to improve the "quality" of the foundations in our new homes is to backfill with as much stone as possible and use a waterproofing "membrane" on the outside of the poured concrete walls.
Nine foot poured concrete walls are standard pricing in our homes. We ALSO include a rubber-like membrane sprayed on the outside of these concrete walls. This is an effective barrier against moisture soaking through the concrete and getting into your finished, or unfinished lower level. This membrane is quite a bit more effective than the standard tar coating and is the same treatment used by firms that guaranty basements against moisture penetration for 10 years.
We also backfill around the excavation of our poured walls with stone as high as our excavation will allow us to go. Current code requires us to backfill with stone over the drain tile 1 foot. We usually end up backfilling with stone 5, 6 or more times that. In doing this, we take pressure off the foundation by moving water down to the drain tiles as expediently as possible. Water that sits on a foundation is likely to eventually soak through, even with 10 inch thick poured concrete walls. With the stone, there is room for expansion in areas that have a lot of clay and don't drain well such as on the North and Northeast suburbs. It costs us a little more, but we consider it an inexpensive insurance policy against future problems with foundations and is included with all of our homes.
As always, surface water management is a crucial factor in keeping a basement dry and that is managed by effective rough and finish grading in landscaping, proper gutter and downspout-downspout extension operation, and home maintenance.
