This on-line utility provides a convenient reference for spans for common species of Canadian and U.S. dimension lumber, fully in accord with United States building codes and Federal Housing Administration [FHA] requirements.

The information provided by this utility applies only in the United States.

Deflection Limits

The following deflection limits are taken into account:
Floor Joists L/360
Ceiling Joists L/240
Rafters [snow/drywall] L/240
Rafters [snow/no drywall] L/180
Rafters [no snow/drywall] L/240
Rafters [no snow/no drywall] L/180

For further information about the assumptions used in calculating spans, please contact Erika Mayer at the Canadian Wood Council.