Roof Snow Load
Frost Depth & Snow Load
The minimum roof or flat-roof design snow load (Pf), a different quantity from ground snow load, where the jurisdiction adopts its own figure.
Roof Snow Load Rules by State
Statewide law governs this topic in many states. Each entry links to that state's full page.
Massachusetts
Some RestrictionsMassachusetts lists a minimum flat roof snow load for every city and town, and requires designers to use whichever is larger: that listed floor or the load calculated from the local…
Rhode Island
Some RestrictionsRhode Island's state table gives each municipality a flat roof snow load alongside its ground snow load, so the roof figure does not have to be derived from the ground value.
Wisconsin
Some RestrictionsWisconsin's dwelling code sets minimum roof snow loads from a state zone map and does not state a ground snow load at all, which is the opposite of how most states publish the figure.
Cities & Counties with Roof Snow Load Rules
3 locations
Other Frost Depth & Snow Load Topics
Frost Line Depth
How deep footings must go below finished grade to sit under the frost line, as adopted locally in IRC Table R301.2 or an amendment to R403.1.4.
Ground Snow Load
The ground snow load in pounds per square foot (Pg) the jurisdiction adopted, which sets what roofs and structures must be designed to carry.
Deck Footing Depth
How deep deck and porch footings must be set, plus the size, attachment and permit thresholds that apply to decks specifically.
Fence Post Depth
How deep fence posts must be set relative to the local frost line, and when a fence needs a permit or an inspected footing.
Frost-Protected Shallow Foundations
Whether the jurisdiction permits a frost-protected shallow foundation under IRC R403.3 instead of digging to the full frost depth, and on what terms.
Building Design Criteria
The full set of local design criteria, wind speed, seismic design category, weathering, termite risk and ice-barrier requirements, as adopted.