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Load classes & width classes

How to dimension scaffolding to EN 12811

2026-06-13·12 min reading

How much may a scaffold deck carry, and how wide must it be? This is determined by two things from the standard DS/EN 12811-1: the load class, which sets the permitted weight per m², and the width class, which sets the deck's width. Here are both tables — and how to choose correctly for the task.

Introduction

A scaffold must be able to carry what is done on it — no more, no less. The European standard DS/EN 12811-1 divides working decks into six load classes according to how much weight they may carry per square metre. Choose too low a class and you overload the scaffold; choose too high and you pay for a heavier and more expensive scaffold than necessary.

The six load classes

The load class specifies the evenly distributed load (weight spread across the whole platform) in kN/m². Rule of thumb: 1 kN corresponds to approx. 102 kg.

ClassUniformly distributed load≈ kg/m²Typical use
10,75 kN/m²~76Inspection and examination — no storage
21,5 kN/m²~153Painting, light cleaning, lighter work
32,0 kN/m²~204Light facade work without heavy material storage
43.0 kN/m²~306Bricklaying and plastering work with material storage
54.5 kN/m²~459Heavy material storage
66.0 kN/m²~612Very heavy storage (e.g. natural stone, concrete)
1,00 m0,50 m0,15 m
Fig. Cut through the working deck: the payload is carried by the deck, and the handrail secures with a handrail at 1.00 m, knee rail at 0.50 m and toe rail at least 0.15 m (DS/EN 12811-1).

Point loads and partial-area load

In addition to the uniformly distributed load, the platform must also be able to carry concentrated loads: a point load F1 on an area of 500 × 500 mm (1.5 kN for classes 1–3, 3.0 kN for classes 4–6) and a smaller point load F2 on 200 × 200 mm (1.0 kN). For the heavy classes 4–6 there is also an increased load on a partial area of the platform. The individual loads are verified separately — not on top of one another. The exact values are given in EN 12811-1, Table 3.

Point loadSite areaLoad class 1–3Load class 4–6
F1500 × 500 mm1,5 kN3,0 kN
F2200 × 200 mm1,0 kN1,0 kN

Width classes (W06–W24)

Where the load class is about weight, the width class is about space: how wide the working platform is. The standard divides the width into seven classes in steps of 0.3 metres. The wider the platform, the more room for both people and materials — but also the heavier the scaffold.

Width classTread width w
W060,6 ≤ w < 0,9 m
W090,9 ≤ w < 1,2 m
W121,2 ≤ w < 1,5 m
W151,5 ≤ w < 1,8 m
W181,8 ≤ w < 2,1 m
W212,1 ≤ w < 2,4 m
W24w ≥ 2.4 m
Fig. Cross-section through the field: width class (W06–W24) indicates work platform width w, measured horizontally between the two supporting columns — independent of load class.

The load class and width class are chosen independently and combined freely to suit the task. The class is shown on the scaffold's signage and in the system's standard sheets. If you want to calculate it specifically, use the calculator "Load class → permitted load", which translates the class into kg per m² and per bay.

Several load classes in one continuous scaffold

On a large construction site, different parts of the scaffolding may be designed for different work — perhaps class 4 there, where the bricklayer has a material store, and class 2 there, where only painting is done. But if it stands as one continuous scaffolding, one cannot automatically count on each section being used for its class. In practice, the lowest design basis is governing, unless the sections are physically separated and signed separately, so it is clear what may be loaded where.

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