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Cross-market term

Scaffold members

The tubes making up a tube-and-fitting or system scaffold: the verticals carrying load to the ground, the horizontals running along the face, and the horizontals running into the building.
  • 4Markets
  • NoSame thing everywhere
  • 6Calculators

What it is called, by market

One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.

  • United Kingdom

    Same word, different thing

    standard, ledger, transom

    also upright, putlog, brace, sole plate

    STANDARD is the vertical, LEDGER the horizontal along the face, TRANSOM the horizontal across it. A putlog scaffold has one row of standards and rests its transoms in the wall, which is a different structure from an independent scaffold.

  • Australia

    Close, not identical

    standard, ledger, transom

    also upright, bearer, putlog

    British terms under Australian standards, with bearer used where British usage says transom in some system-scaffold documentation.

  • United Statesyours

    Same word, different thing

    post, runner, bearer

    also upright, ledger, leg, putlog

    POST is the vertical, RUNNER the horizontal along the face, BEARER the one across it carrying the platform. Ledger is used loosely for a runner — and in American CARPENTRY a ledger is the board bolted to a wall carrying a deck, which is not a scaffold member at all.

  • Canada

    Same word, different thing

    post, ledger, bearer

    also runner, upright, stringer

    As the United States, with the same carpentry collision on ledger.

The governing standard, by market

  • United Kingdom

    TG20 / BS EN 12811-1

    Good practice guidance for tube-and-fitting scaffolds, and the performance requirements for temporary works equipment.

  • United States

    OSHA 29 CFR 1926 Subpart L

    Scaffolds: capacity, platform construction, access, fall protection and competent-person duties.

Calculators for this

Each works in either measurement system, and the terminology on the page follows whichever market you have selected.

Scaffold Face Area and Hire Quantity Calculator →Scaffold Base Plate Bearing Pressure Calculator →Temporary Construction Fence Panel Count Calculator →Guardrail Toe Board Height and Quantity Calculator →Extension Ladder Setup Angle & Placement Safety Checker →Extension Ladder Size Calculator →

Frequently asked questions

Which tube is which, across the markets?
Take them by direction and the translation is mechanical. The VERTICAL that carries load down to the ground is a standard in British and Australian usage and a post or leg in American. The HORIZONTAL running along the face of the building, tying the standards together lengthways, is a ledger in British usage and a runner in American. The horizontal running ACROSS, from the outer standards towards the wall, carrying the boards, is a transom in British usage and a bearer in American. The trap is ledger, which American practice also uses loosely for a runner, so a mixed-vocabulary drawing can have ledger meaning either the along-the-face member or the across member depending on which page you are reading. Direction is unambiguous and the words are not: describe the member by where it runs before ordering anything.
What is the difference between a putlog and an independent scaffold?
Whether the building is carrying part of the scaffold. A PUTLOG scaffold has a single row of standards away from the wall, and the inner end of each transom — the putlog — is flattened and rests in a hole left in the masonry, so the wall takes that load. It is cheap, it uses far less tube, and it only works on a building with masonry able to take it, which in practice means new brickwork being built up behind it. An INDEPENDENT scaffold has two rows of standards and stands on its own, tied to the building for stability but not supported by it, which is why it is the normal choice for refurbishment, for cladding, and for anything where the wall's condition is not known. The difference is not a preference: putting a putlog scaffold against a wall that cannot take it is how a scaffold comes down.
Why does a scaffold have a sole plate, and what happens without one?
Because the base plate at the foot of each standard concentrates the whole leg load onto a small area, and most ground cannot take it. The sole plate — a timber or a proprietary spreader under the base plate — spreads that load over enough ground to keep the bearing pressure within what the soil can carry. Without one, or with one on soft or recently disturbed ground, the standard settles: not dramatically, just enough to take the scaffold out of level, which throws load onto the ties and the braces that were never designed to carry it. It is why the ground beneath a scaffold is a design input rather than a detail, why scaffolds on pavements sit on plates rather than on the slabs, and why a scaffold erected over a newly backfilled trench is a specific and well-known hazard.