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Guide

Aluminum vs steel scaffolding

Aluminum (in British English, aluminium) scaffolding is lighter to carry; galvanised steel carries more and takes more abuse. How big the differences are depends on the part, so this guide uses the manufacturers’ own catalogues and approvals rather than rules of thumb.

By Ole Emil Frikstad Urstad · How the numbers are computed ·

Aluhak Modul scaffolding around a house of 11.4 × 5.3 m with a gabled roof (eaves 4.5 m, ridge 6 m), drawn by the ScaFix 3D model
Aluhak Modul around the example house, as ScaFix draws it in 3D.

Is aluminum or steel scaffolding better?

It depends on the job. Aluminium parts weigh roughly half as much: Layher lists a 2.00 × 0.73 m frame at 18.8 kg in steel and 8.6 kg in aluminium. Steel carries heavier load classes, takes rough handling and cost less in Layher’s 2019 list. For hand-carried facade work aluminum saves effort; for heavy trades, steel usually wins.

How much lighter is aluminium scaffolding?

The answer varies by component, and the frame is where the gap is largest. These figures come from Layher’s SpeedyScaf catalogue (edition 04.2023, published by Layher and hosted by a Danish dealer) and HAKI’s assembly instructions for HAKI Universal (2021):

ComponentSteelAluminiumAluminium as share of steel
Layher frame 2.00 × 0.73 m18.8 kg8.6 kg46 %
Layher deck 3.07 × 0.32 m19.3 kg (steel deck LW)11.5 kg60 %
HAKI plank 3.05 m × 230 mm18.1 kg11.2 kg62 %
HAKI decking per m², 230 mm planks26.2 kg/m²16.5 kg/m²63 %

Sources: Layher SpeedyScaf catalogue 2023/2024, HAKI Universal assembly instructions.

So an aluminium facade scaffold is not “half the weight” overall. Frames save more than half, decks about 40 %, and base jacks, ties and couplers are steel in both systems. Steel has not stood still either: Layher’s steel deck LW uses higher-tensile steel to cut weight against its older T4 deck (19.3 kg against 21.5 kg at 3.07 m) while keeping the same load ratings.

Why does part weight matter on site?

Because a facade scaffold is built by hand, one part at a time, often passed up from lift to lift. The HSE’s manual handling guide gives a guideline weight of 25 kg for men and 16 kg for women when a load is held close to the body between knuckle and elbow height, and much less at arm’s length or above the shoulder. It stresses that these are not safe limits, only filters for spotting low-risk tasks (HSE INDG143, rev. 4, 2020). A steel frame is inside those figures when held close; reaching up with it is another matter. Layher also points to logistics: fewer and lighter parts make better use of truck capacity (Layher SpeedyScaf brochure).

HAKI Universal scaffolding (2.5 m bays, 1.01 m deep) around a house of 11.4 × 5.3 m with a gabled roof (eaves 4.5 m, ridge 6 m), drawn by the ScaFix 3D model
HAKI Universal (2.5 m bays, 1.01 m deep) around the example house, as ScaFix draws it in 3D.

Which carries more load?

Steel, in most systems. In Layher’s catalogue, SpeedyScaf 0.73 m in hot-dip galvanised steel goes up to load class 4, the same width in aluminium up to load class 3, and the 1.09 m steel version up to load class 6, depending on deck and bay length. HAKI rates its aluminium planks at load class 6 up to 2.5 m long but class 5 at 3.05 m, while its steel planks stay at class 6 across the range. In the US the rule is about safety margin rather than class: under 29 CFR 1926.451(a)(1), each scaffold and component must support its own weight and at least four times the maximum intended load, whatever it is made of (29 CFR 1926.451).

Load class (EN 12811-1)Uniform loadTypical use
32.0 kN/m²Painting, rendering, light facade work
54.5 kN/m²Heavier trades with stored material
66.0 kN/m²Masonry with stacked blocks

The uniform loads are as printed in HAKI’s instructions. Lighter decks do have one structural advantage: less self-weight on the standards. In HAKI’s table for a 770 mm bay with five decked lifts at load class 3, aluminium planks allow a 74 m build height against 70 m with steel planks. What each class means in practice is covered in our guide to scaffold load classes.

How long does galvanised steel last?

A long time, if the zinc is intact. Layher states that its steel components are hot-dip galvanised to EN ISO 1461. The American Galvanizers Association lists zinc loss rates by the ISO 9223 corrosivity categories: 0.1–0.7 µm a year in C2, 0.7–2.1 µm in C3, 2.1–4.2 µm in C4 and 4.2–8.4 µm in C5. For a 100 µm coating in a C3 environment, that gives 47 to 143 years before first maintenance (AGA).

Scaffold parts rarely die of corrosion, though. They are retired after damage: bent tubes, crushed decks, deformed connectors. Steel tolerates being dropped and thrown into a truck better than aluminium, which dents more easily. Inspect both types for damage before every use.

Can you mix aluminium and steel parts?

Within one manufacturer’s system, yes, but only as that system’s approval allows. Layher’s German approval for the aluminium Blitz 70 system lists steel base jacks, gantry frames, ties and braces that are regulated under the steel system’s approval, and the steel approval in turn lists aluminium guardrails, beams and stairs (DIBt Z-8.1-844.pdf)). Both are approved for the same standard configuration: facade scaffolds up to 24 m, 0.732 m wide, bays up to 3.07 m.

Mixing brands is different. HAKI’s instructions say its system scaffold must not be combined with another make without a separate load-bearing assessment, and that mixing suppliers can invalidate insurance cover. Adding ordinary tubes and approved couplers is allowed. OSHA sets the same two limits in US law: parts from different manufacturers may be intermixed only if they fit together without force and the user keeps the scaffold’s structural integrity, and parts of dissimilar metals, such as aluminum decks on steel frames, may be used together only after a competent person has determined that galvanic action will not weaken any component below the four-times rule (29 CFR 1926.451(b)(10) and (b)(11)).

Which is cheaper?

In Layher’s 2019 German list (the latest we could open), the aluminium 2.00 × 0.73 m frame cost about one and a half times the steel frame, and the 3.07 m aluminium deck about 1.7 times the steel deck LW (Layher Blitz price list 04.2019, dealer copy). Hire is priced by area and time rather than by material, so the difference matters most to owners; dated ranges are on our page on scaffolding cost.

Is aluminum or steel the greener choice?

Both metals are recycled at high rates: a 2012 survey of UK demolition contractors found 93 % of heavy steel sections and tubes recycled and 7 % reused (SteelConstruction.info), and European Aluminium cites collection rates above 95 % for aluminium in buildings (European Aluminium). We found no environmental product declaration for a scaffold system from Layher, HAKI or PERI, although Layher claims an up to 40 % smaller carbon footprint for its CO2-reduced steel deck LW (Layher).

So which should you choose?

  • Aluminium: small crews, hand-carried facade work, mobile towers (mobile scaffold towers), sites with poor vehicle access, and work at load class 3 or below.
  • Steel: masonry and heavy trades (class 4–6), industrial work, long hire periods and rough handling.
  • Both: many contractors run steel for the structure and add aluminium decks, beams or stairs where the approval allows it. Compare the two in a real system, such as Layher Blitz or the all-aluminium Aluhak Modul.

ScaFix lists the parts of each system, steel or aluminium, so the weight of a planned scaffold can be read off before anything is ordered.

Weights, load classes and build heights here come from the makers’ catalogues and approvals and are planning information, not a structural check. The manufacturer’s assembly instructions and, in the UK, the Work at Height Regulations and NASC TG20, or in the US OSHA 29 CFR 1926 Subpart L, decide how a scaffold is built; a competent person must inspect it before use.

Frequently asked questions

How much does an aluminium scaffold frame weigh?

In Layher’s 2023 catalogue, a 2.00 × 0.73 m aluminium frame weighs 8.6 kg. The same frame in galvanised steel weighs 18.8 kg.

Is aluminium scaffolding as strong as steel?

Not in most systems. Layher rates its 0.73 m aluminium SpeedyScaf to load class 3 and the steel version to class 4; wider steel versions reach class 6.

Does aluminium scaffolding rust?

Aluminium does not rust the way steel does, but it dents more easily. Steel scaffolding is hot-dip galvanised, and the zinc layer protects it for decades in most climates.

Can I use aluminium decks on a steel scaffold?

Only where the system’s approval and instructions list them. Layher’s approvals, for example, list aluminium parts in the steel system and steel parts in the aluminium system.

Why is aluminum scaffolding more expensive?

The material and the extruded profiles cost more. In Layher’s 2019 German list prices, the latest we could open, aluminium frames and decks cost roughly 1.5 to 1.7 times their steel equivalents.

Is aluminum scaffolding OSHA-compliant?

It can be: OSHA approves no material, but 29 CFR 1926.451 requires every component to hold its own weight plus four times the maximum intended load, and a competent person must inspect the scaffold before each shift. Aluminum and steel parts may be combined only after a competent person rules out galvanic weakening.

Sources

Primary sources used for this article, with the date each was read.