What loads act on a scaffold?

Three main loads: (1) Dead load — self-weight of the scaffold (tubes, boards, fittings) at approximately 0.3 kN/m per lift. (2) Imposed load — workers, tools, and materials on the platforms (0.75-6.0 kN/m² depending on load class). (3) Wind load — horizontal force from wind pressure acting on the scaffold face and any sheeting/netting.

What is a TG20 compliant scaffold?

TG20:13 is the NASC (National Access & Scaffolding Confederation) technical guidance for tube and fitting scaffolding. A TG20 compliant scaffold follows standard configurations that have been pre-designed — if the scaffold fits within TG20 parameters (height, load class, tie pattern, base conditions), no specific design is needed. Scaffolds outside TG20 limits require a bespoke engineering design.

When does a scaffold need a specific design?

A scaffold needs a bespoke design (by a competent engineer) when it falls outside TG20 parameters: height over 50m, non-standard configurations (cantilevers, bridges, loading bays), fan or catch scaffolds, heavy-duty loading (Class 4+), sheeted scaffolds in exposed locations, scaffolds with incomplete tie patterns, or any unusual arrangement. The design must be by a qualified scaffold designer.

How does wind loading affect scaffold design?

Wind creates horizontal loads that must be resisted by ties and bracing. An unsheeted scaffold has low wind load (30% solidity ratio). A sheeted scaffold can have 100% solidity, dramatically increasing wind loads — this is why sheeted scaffolds need more ties and may require a specific design. In high winds (over 17 m/s), scaffolding work should stop.

What is the capacity of a standard scaffold tube?

A 48.3mm × 4.0mm wall scaffold tube (BS EN 39) has a yield strength of approximately 25 kN in compression for short lengths. As the effective length increases (taller scaffolds), buckling reduces the capacity. At 2m lift height: approximately 25 kN. At 4m: approximately 15 kN. TG20 provides detailed standard capacities based on height and configuration.

TradeCalculator

Scaffold Design Load Calculator — Dead, Imposed & Wind Loads

Calculate scaffold design loads per TG20 and BS EN 12811. Checks dead load, imposed load (trade + materials), wind load, and standard tube capacity.

Scaffold Height

Total height of scaffold

Load Class

Determines the imposed load

Wind Speed

Basic wind speed for your location

Scaffold Face

Sheeting increases wind load significantly

How We Calculate This

This calculator determines the design loads on a scaffold and checks them against standard tube capacities per TG20:13 and BS EN 12811.

Load calculation

Dead load: ~0.3 kN/m per lift (tube and fitting self-weight)
Imposed load: Load class × platform area × boarded lifts
Wind load: 0.613v² × solidity ratio × wind area
Standard check: Total vertical load vs tube compressive capacity

Frequently Asked Questions

Related Calculators

Scaffold Hire Cost Calculator

Calculate scaffold hire cost from building perimeter, height and hire period.

Scaffold Load Class Calculator

Determine scaffold load class by trade use with platform loading check.

Tower Scaffold Height Calculator

Calculate tower scaffold maximum height from base dimensions with stabiliser requirements.

Scaffold Tie Calculator

Calculate scaffold tie pattern per TG20 with tie type selection.

Scaffold Board Calculator

Calculate scaffold platform boards, toe boards and ladder access per bay.

Last updated: March 2026

All calculations are estimates. Verify with your supplier.