Double ledger and lattice ledger
A ledger with top and bottom chord, braced by posts or a truss, used where a single ledger would bend too much under wide bays or heavy loads.
Also called: reinforced ledger, heavy-duty ledger, lattice ledger, truss ledger
A plain tubular ledger reaches its limit at some point. If the bay gets wider, heavy material sits on the deck or a standard has to be carried in mid-bay, you need a ledger with more depth. That is the double ledger: two chords one above the other, linked by posts or struts. With a truss between them it becomes a lattice ledger.
Crews have plenty of nicknames for these parts – on German sites they are called ships, boats or combs because of their shape. All of them mean the strong ledger that steps in where a normal one would deflect too far.
Design and variants
A double ledger has a top chord on which the decks rest and a bottom chord that takes tension. Both have wedge heads at the ends, connected to one disc or to two discs one above the other, depending on design. The top chord may be round tube or a U-profile to match the deck system.
- Double ledger: mostly used across the scaffold for wide bays or high loads, or as a bearer on which new standards are set with half couplers and spigots.
- Lattice ledger: longer, with a truss, for spans of 2.57 or 3.07 m along the scaffold – in birdcages, work platforms or bridging small openings.
- Material: mainly galvanised steel, in some systems aluminium.
- Not to be confused with the much longer lattice girder that spans gateways or canopies.
Fitting
- Establish the required load class and span and pick the ledger the instructions specify.
- Offer it up to both standards, slide the wedge heads over the discs and insert the wedges. With two connections per side, keep to the sequence in the instructions.
- Align, then hammer every wedge tight.
- Lay decks and lock them; on U-profiles with the matching deck lock.
- If standards are to stand on the ledger, clamp spigots with half couplers to the top chord at the specified spacing and slide the standards on. That extra load must be covered by the design.
Checks and mistakes
- A double ledger is not a blank cheque; its limits are in the system documentation too.
- The members between the chords must be complete and undamaged. One torn-off post costs a lot of capacity.
- Watch for twist: lattice ledgers bent in transport sit crooked and will not connect cleanly.
- Top chord profile and deck must match.
- On used parts inspect every welded node, not just the ends – cracks at inner nodes are easily missed.
Where they are used
In practice double ledgers appear at brackets, at steps from wide to narrow scaffolds, at openings for ladder or stair access and on industrial work platforms. Lattice ledgers are a common sight in birdcage scaffolds under hall ceilings, where large, load-bearing areas are needed. Used reinforced ledgers are listed under ledgers.