Limitations for notches and holes in floor and roof joists

Diagram 4B.1 Limitations for notches and holes in floor and roof joists a) limits for notching positions within which notching may take place without a design check clear span: simply supported joist (not a trimmer, trimming joist or beam) 0.25 L max, 0.2 L max, 0.07 L min, 0.1 L min, 0.07 L min, 0.25 L max 0.125 d max, 0.125 d max b) alternative limits for notching Note: This alternative notching may occur at both ends without a design check alternative positions for notching alternative position for notching 0.15 d max, 0.15 d max c) limits for drilling holes not exceeding 0.25 d diameter may be positioned on the centre line between 0.25 L and 0.4 L from a support without a design check not closer than 3 x diameter no hole to be closer than 100 mm to any notch (and vice-versa) d) end trimming end of joists, trimmers, etc. supported by a joist hanger should be shaped to house the thickness and profile of the joist hanger chosen see para 4B.6 d ≤ 250 mm d ≤ 250 mm Key: d = means not greater than, L = clear span