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AIR RE UIREMPSUS the stringer span(see provisions below). If the total <br /> tairs,stair stringers,and stair guards shall meet the vertical height of a stairway exceeds 12'-0",then an <br /> requirements shown in Figure 27 through Figure 34 and intermediate landing shall be required.All intermediate <br /> Table 6 except where amended by the local jurisdiction. stair landings must be designed and constructed as a <br /> All stringers shall be a minimum of 2x12. Stair stringers free-standing deck using the details in this document. <br /> shall not span more than the dimensions shown in Figure Stairs shall be a minimum of 36" in width as shown in <br /> 28.If the stringer span exceeds these dimensions,then a Figure 33 [R311.7].If only cut stringers are used,a <br /> 4x4 post may be provided to support the stringer and minimum of three are required.For stairs greater than <br /> shorten its span length.The 4x4 post shall be notched 36"in width,a combination of cut and solid stringers <br /> and bolted to the stringer with(2) ''/a" diameter through- can be used,but shall be placed at a maximum spacing <br /> bolts with washers per Figure 8.The post shall be of 18" on center(see Figure 29).The width of each <br /> centered on a 12" diameter or 10" square,6"thick landing shall not be less than the width of the stairway <br /> footing.The footing shall be constructed as shown:in served.Every landing shall have a minimum dimension <br /> Figure 34 and attached to the post as shown in Figure 12. of 36"measured in the direction of travel and no less <br /> An intermediate landing may also be provided to shorten than the width of the stairway served[R311.7]. <br /> Figure 27. Tread and Riser Detail Figure 28. Stair Stringer Requirements <br /> —riser may be open,but <br /> shall not allow the <br /> passage of a 4"diameter <br /> N sphere <br /> 10"minimum <br /> i <br /> {tread width <br /> 7-3/4"maximum,, { <br /> riser,height shall 1, - risers:1x material,minimum <br /> not deviate from �.3 <br /> another by more than 318" <br /> one another by <br /> more than 31fi"!� 1 ��7 <br /> treads:see Figure 28 and Table 6 <br /> ---3/4"-1-114"nosing;nosing max.soon 7'-0"for southern pine <br /> Li -- --- <br /> = <br /> shall not deviate from one <br /> max.span=6'Q-for attrar Table 1 species `-- -----, <br /> CUT STRINGER <br /> 1 max.span=16'-6"for southern pine <br /> ■ <br /> max,span=13'-3"for other Table 1 species <br /> SOLID STRINGER <br /> Figure 29. Tread Connection Requirements <br /> Attachment per tread at each stringer or ledger- <br /> 2x <br /> edger ----! Table 6. Mirlirnum Tread Size for Cut and Solid <br /> i 2x or 5/4 treads-(2)8d threaded nails or(2#8 screws>_2-1/2"long{ Stringers' <br /> 3x treads-(2)16d threaded nails or(2)#8 screws 2:3-1/2"long Cut Solid <br /> Species <br /> stringer Strin er Strin er <br /> -----� <br /> treads:2x_or 514 board treads:see Table 6 �t Southern Pine 2x4 or 5142x6 <br /> Douglas Fir Larch, <br /> I; 1� Hem-Fir,SPFZ 2x4 or 514 2x8 or 3x4 <br /> j( 18"max l 18"max 36"max ',. Redwood,Western Cedars, <br /> '►– Ponderosa Pine3, Red Pin 2x4 2x4 or 5/4 2x10 or 3x4 <br /> 2x4 ledgers.each side,full depth of 1.Assumes 300 ib concentrated load,0288 deflection limit,No. <br /> tread;attach with(4)14d threaded 2 grade,and wet service conditions. <br /> stringers—% nails or(4)#8 wood screws 23"long 2.Incising assumed for refractory species including Douglas fir- <br /> CUT STRINGER SOLID STRINGER larch,hem-fir,and spruce-pine-fir. <br /> 3.Design values based on northern species with no incising <br /> assumed. <br /> American Forest&Paper Association <br /> i _ <br />