SPEC SHEET No. 21.2 holes in spec Joist (sji) December 2024
100mm
x
50mm or less holes in any location outside exclusion zones and minimum of 300mm from supports
x
150mm 150mm
x
x
End Support
x
x
Intermediate Support
Exclusion Zone
Cantilever Support
x = Larger of Joist Height / 2 or 150mm
Consider clusters of holes as a single larger hole
A1
h1
A2
A3
h3
Hole
Minimum distance to the hole is the greater of
h
A h1 x 2 h2x 2 h2x 2 h3x 2 A1
1
h2 h3 h4 A h
h2
A2
H4
Measured from
1
A2 A3 A3 A2
A1
h2 x 2 h3 x 2 h3 x 2 h4 x 2
Support h1 h3 h2 h2 Support
Minimum distance from support per relevant ITI Spec Joist (SJI) I-Joists Distance to Hole tables Longest side of rectangular hole or diameter of round role
To use: 1. Minimum allowable span to be 2x the distance from hole location from support per tables 2. Select the depth of I-Joist in which holes will be penetrated 3. Select the row which corresponds to the span. For spans which fall between those listed round up to the larger span 4. Select the column which corresponds to the hole size. Always round the hole size up. Rectangular holes not listed may be assessed as 0.75 the diameter of a round hole for the largest side of the rectangle 5. The intersecting value is the nearest allowable distance from the inside face of the support to the nearest edge of the hole 6. Double check the location by cross referencing the allowable distance of the opposing support 7. When multiple holes are required always consider placing the smallest holes closest to the support Notes: 1. CUT HOLES CAREFULLY. DO NOT OVER CUT HOLES 2. DO NOT CUT THE FLANGES OF THE I-JOISTS 3. Holes may be located within the full depth of the web provided there is a minimum of a 5mm gap from the bottom of the hole to the flange 4. No holes are to be cut into a cantilever 5. Multiple holes may be spaced closer than specified however the assessment should be made for a larger hole whereby the smaller holes are enclosed within the larger hole 6. Hole locations are only valid on joists supporting uniformly distributed loads only and where the joists are spanning no greater than the allowable maximum span