Jobsite Material Stacking Limits (OSHA 1926.250)
Three stacking rules sharing one idea and one trap.
Example
You enter
- Material brick
- Stack or pile height (ft) 5
- Block height (in; for the tier count) 8
- Block length (in; half of this per tier) 16
- Lumber handled manually? no
You get
- Max height (ft) 7
- Taper required (in) 2
- Taper provided SHORT by 2.0 in
- Height over (ft) 0
Checked against published worked examples from: Occupational Safety and Health Administration.
Details, formula, and sources
ScopeThe idea: past a threshold a stack must lean AWAY, because a vertical face of loose units topples toward whoever is standing at it -- the person unstacking, at the moment they have removed what held the face. The trap: the threshold and the ceiling are DIFFERENT numbers, so a stack can be legal in height and illegal in shape. A 5 ft brick stack is nowhere near the 7 ft limit and already owes 2 in of taper. Brick: 7 ft max, 2 in per foot above 4. Block: half a block per tier above 6 ft -- an 8 ft stack of 8 in block owes 24 in. Lumber: 20 ft, but 16 if handled MANUALLY, so the same pile is legal or not depending on how it comes DOWN, not how it went up.
Formula or tablebrick: ceiling 7 ft, taper = (height - 4 ft) x 2 in per foot above the 4 ft level; masonry block: tiers above 6 ft = ceil((height - 6 ft) x 12 / block height), taper = tiers x half the block length; lumber: ceiling 20 ft, or 16 ft where handled manually.
Source and editionOSHA 29 CFR 1926.250, a US federal regulation in the public domain, quoted directly.
Free access29 CFR is published in full at no cost by OSHA and the eCFR.
What governsEstimate. AHJ and licensed professional govern.
API field namesmaterial, stack_height_ft, block_height_in, block_length_in, handled_manually, max_height_ft, taper_required_in, taper_shortfall_in, height_over_ft
- Brick not more than 7 ft; tapered back 2 in per foot above the 4 ft level29 CFR 1926.250
- Masonry block tapered back one-half block per tier above the 6 ft level29 CFR 1926.250
- Block ceiling the section states none - only the taper - and none is inventedstated scope limit
- Lumber not more than 20 ft, or 16 ft where handled manually29 CFR 1926.250
- Threshold vs ceiling different numbers, so a stack can be legal in height and illegal in shapearithmetic on the two figures
- Not checked bearing, banding, bags and bundles, aisles, edge clearance, supporting floor capacitystated scope limit