Rhode Island Frost Depth: 3 Feet 4 Inches in Most Towns

Rhode Island deletes the model code's Table R301.2 and its national figures outright and substitutes its own. The substituted statewide table records a frost line depth of 40 inches, and a companion table titled the Rhode Island Snow Load, Wind Speed and Frost Depth Table gives the figure municipality by municipality as 3 feet 4 inches, which is the same 40 inches expressed in feet and inches. Every mainland community carries that value. The one departure is New Shoreham, the town covering Block Island, at 2 feet 6 inches: the moderating effect of being ten miles offshore. Because Rhode Island substitutes its own table rather than reprinting a national map, these depths are the state's own numbers, which is what makes them quotable as adopted local law rather than reference data.

Footing depth is verified at the foundation inspection before concrete is placed. A footing above the depth listed for the municipality will not pass and must be corrected. The state code applies uniformly, so the requirement does not change between neighbouring towns: with the single exception of New Shoreham, where the shallower figure is the adopted one.