Insulated foundations have become the norm in recent years in the Northeast, but there are many ways to achieve the desired strength and insulation value. It's important to decide what R-values you want before you select a system, since some methods lend themselves to achieving high Rvalues and some don't. The criteria I use to determine appropriate R-values below grade include: Building code requirements. Increasingly, building codes are addressing foundation heat loss. In New York State the code requires R- 11 insulation. But there is a "flexible" component to the code that allows reduced R-values in one part of a house when another part exceeds code, and when the net effect on the building's energy performance will be the same. Expected use of