Ledger Schedules on Commercial Steel Drawings

A ledger schedule is a small table on a structural drawing that maps short ledger marks (L1, L2, L3) to actual steel angle sizes. Ledgers are the steel angles bolted around the perimeter of a building to support roof joists, decking, or wall systems.

The schedule is the only place the actual angle size is written. On plan pages, every ledger callout shows just the mark.

What's in a Ledger Schedule

LEDGER (L) SCHEDULE
MARK     SECTION                           ATTACHMENT
L1       L5X5X5/16 STEEL ANGLE             3/4" THRU BOLTS @ 24" O.C.
L2       L4X4X1/4 STEEL ANGLE              1/2" EPOXY ANCHORS @ 32" O.C.
L3       L6X4X3/8 STEEL ANGLE              5/8" THRU BOLTS @ 16" O.C.

Three things to look for:

Mark — what appears on plan pages (e.g. L1)
Section — the actual angle size (L5X5X5/16 is a 5"×5" leg, 5/16" thick)
Attachment — bolt or anchor spec, often shared across ledgers

Why Ledgers Matter for Pricing

Ledgers are deceptively expensive. A 200-foot perimeter wall with L5X5X5/16 ledger comes out to about 2,000 lbs of steel. That's a meaningful BOM line item, and missing it on a takeoff means undercounting by 5-10% on a typical commercial shell building.

The mark is also where it's easy to miss something. L1 appears in the same font and size as grid bubbles (L1 in the Lotus convention) on the same drawing. Software that doesn't distinguish ledger marks from grid references will either miss the ledgers entirely or flag every grid as a fake ledger.

What's Tricky About Ledger Schedules

The angle size string varies in format. L5X5X5/16, 5x5x5/16 STEEL ANGLE, 5"x5"x5/16" all describe the same section.
Some schedules don't include the STEEL ANGLE suffix and expect you to know.
Mixed-leg angles (L6X4X3/8 — 6" leg + 4" leg) need to be read carefully because the leg orientation matters for connection design.
Some drawings combine ledgers and angles into a generic "STEEL ANGLE SCHEDULE" instead.

Steelflo handles all of these formats — the schedule extraction validates against the AISC angle database with a strip-trailing-descriptor fallback so 5x5x5/16 STEEL ANGLE resolves to L5X5X5/16 correctly.

FAQ

Q: Are ledger marks always L1, L2? Common, but not universal. Some firms use LDG1 or LD1. Always check the schedule for the project.

Q: Can a single drawing have multiple ledger schedules? Yes — sometimes split by perimeter location (north wall, south wall) or by elevation. Read all of them.

Q: What if my takeoff doesn't pick up ledgers? Most likely the software didn't read the schedule sheet. See why most takeoff software misses schedule keys.