Deck Construction Joist Span Charts
Prescriptive Residential Deck Construction Guide Based on the 2021 IRC
Deck Ledger Connection to Band Joist
60 Live Load or 70 Ground snow Load
Notes:​
a. Interpolation permitted. Extrapolation not permitted.
b. Ledgers shall be fleshed in accordance with Section R703.4 to prevent water romcontacting house band joist.
c. Dead load = 10psf
d. The tip of the lag screw shall fully extend beyond the inside face of the band joist.
e. Sheathing shall be wood structural panel or solid sawn lumber.
f. Sheathing shall be permitted to be wood structural panel, gypsum board, fiberboard, lumber or foam sheathing. Up to 1/2in thickness of stacked washers shall be permitted to substitute up to 1/2in of allowable sheathing thickness where combined with wood structural panel or lumber sheathing.
Deck Joist Span Lengths
60 Live Load or 70 Ground snow Load
Notes:​
For SI: 1in = 25.4mm, 1ft = 304.8mm, 1lb / sqft = 0.0479kPa, 1lb = 0.454kg
NP= Not Permitted
​
a. Dead load = 10psf
b. No. 2 grade, wet service factor included.
c. L/Δ = 360 at main span
d. L/Δ = 180 at cantilever with a 220lb point load applied to end.
e. Includes incising factor.
f. Incising factor not included.
g. Interpolation allowed. Extrapolation not allowed.
Deck Beam Span Lengths (ft-in)[a,b]
60 Live Load or 70 Ground snow Load
Notes:​
For SI: 1in = 25.4mm, 1ft = 304.8mm, 1lb / sqft = 0.0479kPa, 1lb = 0.454kg
​
a. Interpolation allowed. Extrapolation not allowed.
b. Beams supporting a single span of joists with or without cantilever.
c. Dead load = 10 psf, L/Δ = 360 at main span, L/Δ = 180 at cantilever. Snow load
not assumed to be concurrent with live load.
d. No. 2 grade, wet service factor included.
e. Beam depth shall be equal to or greater than the depth of intersecting joist for a
flush beam connection.
f. Beam cantilevers are limited to the adjacent beam’s span divided by 4.
g. Includes incising factor.
h. Incising factor not included.
i. Deck joist span as shown in Figure R507.6.