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Table 2. Roof Rafter Maximum Horizontal Span (feet - inches)1 Assumed Vintage Nominal Size Actual Size Non-Tile Roof2 Tile Roof3 Rafter Spacing 16” o.c. 24” o.c. 32” o.c. 16” o.c. 24” o.c. 32” o.c. Post-1960 2x4 1½”x3½” 9’-10” 8’-0” 6’-6” 8’-6” 6’-11” 5’-6” 2x6 1½”x5½” 14’-4” 11’-9” 9’-6” 12’-5” 10’-2” 8’-0” 2x8 1½”x7¼” 18’-2” 14’-10” 12’-0” 15’-9” 12’-10” 10’-3” Pre-1960 2x4 1¾”x3¾” 11’-3” 9’-9” 7’-9” 10’-3” 8’-6” 6’-9” 2x6 1¾”x5¾” 17’-0” 14’-0” 11’-3” 14’-9” 12’-0” 9’-9” 2x8 1¾”x7¾” 22’-3” 18’-0” 14’-6” 19’-0” 15’-6” 12’-6” Beyond a visual review by the Contractor checking for unusual sagging or deterioration, some CBOs may want additional assurance that the roof structure complies with structural building code requirements. Table 2 is an optional table some CBOs may elect to use to provide additional assurance by requiring a check of existing roof rafter spans, and supports optional criteria 1.B.5 and 1.B.6. For post-1960 construction, these span tables match the rafter span tables found in the 2013 California Building and Residential codes. For pre-1960 construction, the rafter span tables are based on structural calculations with lumber sizes and wood species & grade appropriate for older construction. Note 5 below lists the basic assumptions upon which this table is based. Table 2 Notes: 1. See Figure 4 for definition of roof rafter maximum horizontal span. 2. “Non-tile Roof” = asphalt shingle, wood shingle & wood shake, with an assumed roof assembly weight of 10 psf. 3. “Tile Roof” = clay tile or cement tile, with an assumed roof assembly weight of 20psf 4. Unaltered manufactured plated-wood trusses may be assumed to be code compliant and meet intent of Table 2. 5. This table is based on the following assumptions: • Span/deflection ratio is equal to or greater than 180. • For post-1960 construction, wood species and grade is Douglas Fir-Larch No. 2. • For pre-1960 construction, wood species and grade is Douglas Fir-Larch No. 1. • Other wood species and/or grade are also acceptable if allowable bending stress is equal or greater to that listed above. (Attach Table 2 ONLY if the Optional Additional Rafter Span Check is added to the list of Structural Criteria) 1206 W 18th St 09/18/23