When is roof edge protection required?

Under the Work at Height Regulations 2005, edge protection is required wherever someone could fall 2m or more from a roof edge. This applies to all work on flat roofs, pitched roofs near eaves, and during new-build or re-roofing work. Edge protection must be in place before anyone goes onto the roof. Collective protection (guardrails) is preferred over personal protection (harnesses).

What height should roof edge protection be?

BS EN 13374 specifies: top guardrail at least 950mm above the working surface (1100mm in some countries). An intermediate rail at approximately mid-height (475mm) to prevent people rolling underneath. A toe board at least 150mm high at the base to stop materials rolling off. The guardrail must withstand a horizontal force of at least 0.3 kN at any point.

What is a free-standing edge protection system?

Free-standing systems use weighted bases (counterweights) instead of being fixed to the building structure. Advantages: no penetration of the roof membrane, quick to install and move, no structural fixings needed. Disadvantages: counterweights are heavy (20-30kg each), the system takes up space on the roof, and some configurations require engineering checks.

How far apart should edge protection posts be?

Standard post spacing is 2.0m maximum for most proprietary systems. Some heavy-duty systems allow 2.5-3.0m spacing. The spacing must ensure the guardrail can resist the required lateral loads (0.3 kN point load at the top rail) without excessive deflection. For DIY tube and fitting edge protection, 2.0m is the standard spacing.

Do I need mesh or brick guards on roof edge protection?

Mesh infill (or brick guards) is required when small materials could fall through the gap between the top rail and toe board — for example, during bricklaying, roofing, or any work where loose materials are present on the platform. BS EN 13374 Class A (vertical/low pitch) does not require mesh; Class B and C may require it depending on the risk assessment.

TradeCalculator.co.uk

Roof Edge Protection Calculator — Perimeter Guard Rail Quantities

Calculate roof edge protection requirements: post quantities, guardrail lengths, toe boards, and mesh. Covers free-standing, parapet-mounted, and eaves-mounted systems.

Perimeter Length

Total length of roof edge to protect

Post Spacing

2.0m standard maximum

System TypeFixing method for the edge protection

Guardrail Height

950mm minimum per BS EN 13374

How We Calculate This

This calculator determines the components needed for roof edge protection per BS EN 13374, based on the perimeter length and system configuration.

Components

Posts: At 2m maximum centres around the perimeter
Top guardrail: 950mm minimum height, continuous
Intermediate rail: At approximately 475mm height
Toe board: 150mm high at base to prevent material falls

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.

Edge Protection Calculator

Calculate edge protection guardrail posts, height, toe board and intermediate rail.

Last updated: March 2026

All calculations are estimates. Verify with your supplier.