Cantilever Reinforcement Methods – US

P3 Joist Cantilever Reinforcement Methods Allowed – Table 9
 Joist
Depth [in]
 Roof Truss
Span [ft]
ROOF LOADINGS
TL=35psf | LL <20psf TL=45psf | LL <30 psf TL=40psf | LL <40 psf
 12″  16″  19.2″  24″  12″  16″  19.2″  24″  12″  16″  19.2″  24″
9-12  26 N N N  1 N N 1 2 N 1 2 X
 28  N  N N  1 N N 1 2 N 1 2 X
 30  N  N 1  1  N  N  1  2  N  1  2  X
 32  N  N  1  2  N  1  1  X  N  1  2  X
 34  N  N  1  2  N  1  2  X  N  2 X  X
36  N  N  1  2  N  1  2  X  N  2  X  X
 11-7/8 26  N  N  N  1  N N  1  1  N  1  1  2
 28  N  N  1 1 N  1  1  1  N  1 1  2
30  N  N  1  1  N  1  1  2  N  1  1  2
32  N  N  1  1 N  1  1  2  N  1  1  2
 34  N N 1  1  N  1  1  2  N 1  2  2
 36  N N  1  1 N  1  1  2  N  1  2  2
 38  N N  1  2  N  1  1  2  N  1  2  X
 14 26  N  N  N  1  N  N  N  1  N  N  1  1
28  N  N  N 1  N  N  1  1  N N  1  2
 30  N N  N  1  N  N  1  1  N  1  1  2
32  N  N  N 1  N  N  1  1  N 1 1  2
34  N  N  N 1  N  1  1  2  N  1  1  2
 36  N  N 1 1  N  1  1  2  N  1  1  2
 38  N  N 1  1  N  1  1  2  N 1  1  2
 40  N  N 1  1  N  1  1  2  N  1  2  2
16  26  N  N  N  1  N  N  1  1  N  N  1  1
28  N  N  N  1  N  N  1  1  N  N  1  2
 30  N  N  N 1 N  N  1  1  N  1  1  2
 32  N  N  N  1 N  N  1  1  N  1  1  2
34  N  N  1 1  N  N  1  2  N  1  1  2
36  N  N  1  1  N  1  1  2  N  1  1  2
 38  N  N 1  1  N  1  1  2  N  1  1 2
40  N  N  1  1  N  1  1  2  N 1  2  2
42  N  N 1  1  N  1  1  2  N 1  2  X

NOTES:

  1. N = No reinforcement required
    1 = PJIs reinforced with 23/32” wood structural panel on one side only
    2 = PJIs reinforced with 23/32” wood structural panel on both sides or double P3 Joist
    X = Try a deeper joist or closer spacing.
  2. Maximum load shall be 15 psf roof dead load, 50 psf floor total load, and 80 plf wall load. Wall load is based on 3’–0” maximum width window or door openings. For larger openings or multiple 3’–0” width openings spaced less than 6’–0” o.c., additional joists beneath the opening’s cripple studs may be required.
  3. Table applies to joists 12” to 24” o.c. Use 12” o.c. requirements for lesser spacings.
  4. For conventional roof construction using a ridge beam, the Roof Truss Span column above is equivalent to the distance between the supporting wall and the ridge beam. When the roof is framed using a ridge board, the Roof Truss Span is equivalent to the distance between the supporting walls as if a truss is used.
  5. SAF stands for Span Adjustment Factor. SAF is used as defined below.

OPTIONAL:

Table 9 is based on the P3 Joist being used at their maximum span. If the P3 Joist are placed at less than their full allowable span, the maximum distance from the centerline of the hole to the face of any support (D) as given above may be reduced as follows.

D reduced = (L actual/SAF) x D