Design Criteria

Residential Design Criteria*
Criterion
Specification
Ground snow load
15
Wind speed
90 
Seismic design category
A
Weathering
Severe
Frost line depth
12 inches
Termite
Moderate to heavy
Winter design temperature
22ºF
Ice barrier underlayment required
No
Flood hazards
May 2, 1977
Air freezing index
150
Mean annual temperature
59ºF

*Design criteria for buildings constructed in accordance with the Virginia Residential Code. For all other buildings, see Chapter 16 of the Virginia Construction Code (PDF).