Complete Guide to the Hierarchy of Control for Roof Safety and Working at Heights

Working at heights is one of the most common sources of serious risk on commercial buildings.

Roof access for HVAC servicing, solar maintenance, inspections, and repairs is part of normal operations for most facilities. The issue is that many buildings were never designed with safe access in mind.

That’s where the Hierarchy of Control becomes useful. It provides a clear framework for deciding how to manage risk properly, rather than relying on temporary fixes or overcomplicated systems.

For facilities managers, this is especially important when reviewing height safety reports or planning upgrades.

What Is the Hierarchy of Control?

The Hierarchy of Control is a structured approach used to manage workplace hazards. It ranks safety measures from most effective to least effective, helping you prioritise the controls that actually reduce risk.

The five levels are:

• Elimination
• Substitution
• Engineering controls
• Administrative controls
• Personal protective equipment (PPE)

The key idea is simple: The higher up the hierarchy, the more reliable the control.

In height safety, that usually means systems that remove the fall risk entirely are more effective than those that rely on human behaviour.

Why the Hierarchy of Control Matters for Roof Safety

Roofs introduce a mix of hazards:

• unprotected edges
• fragile surfaces
• awkward access points
• equipment positioned near drop-offs
• inconsistent access routes

These risks often develop over time. Equipment gets added, access becomes more frequent, and what was once occasional becomes routine.

The hierarchy helps bring structure to this by asking:

• Can the hazard be removed?
• Can the work be done in a safer way?
• Can we install systems that prevent exposure to risk?
• What procedures are needed?
• What equipment is required as a backup?

If you’re dealing with a report that highlights multiple issues, this guide will help you prioritise what actually matters: Your Roof Audit Found Safety Issues – What Do You Fix First?

Level 1: Elimination – Removing the Need to Work at Height

Elimination is the most effective control because it removes the hazard entirely. In roof safety, this means designing buildings or processes so work at height isn’t required.

Examples include:

• locating plant equipment at ground level
• designing internal access to plant rooms
• using monitoring systems to reduce physical inspections
• prefabricating components to reduce on-site work

In new builds, this is often achievable. In existing buildings, it’s less common, but still worth considering where possible.

Level 2: Substitution – Reducing Exposure to Risk

When elimination isn’t practical, substitution looks at safer ways to perform the task.

Examples include:

• using telescopic tools to carry out work from ground level
• replacing fragile roofing materials with safer alternatives
• using elevated work platforms instead of ladders
• choosing equipment that can be serviced without accessing high-risk areas

Substitution doesn’t remove the hazard completely, but it reduces how often workers are exposed to it.

Level 3: Engineering Controls – Designing Out the Risk

Engineering controls are where most effective height safety systems sit. These are physical systems that reduce or remove risk without relying on user behaviour.

Guardrails

Guardrails provide permanent edge protection. They stop workers from reaching unprotected edges and remove the fall risk altogether.

For many buildings, this is the most straightforward long-term solution.

Learn more about Guardrail Systems

Roof Walkways

Walkways create defined access routes across the roof.

They help:

• keep foot traffic away from fragile areas
• guide workers safely to equipment
• reduce slips and trips
• support regular maintenance tasks

Learn more about Roof Walkway systems

Roof Access Systems

Safe access is often overlooked. Temporary ladders or poor entry points create risk before workers even reach the roof.

Proper systems include:

• fixed ladders
• caged ladders
• internal access ladders
• roof hatches with safe landing zones

Learn more about Roof Access Ladders or Access Hatches

Anchor Points and Static Lines

These systems allow workers to attach harnesses when working near edges.

They can be effective, but they rely on:

• correct use
• training
• ongoing inspection

In many cases, passive systems like guardrails are a simpler and more reliable solution.

Figure out if Static lines or guard rails work better for your site: Static Lines vs Guardrails

Level 4: Administrative Controls – Managing How Work Is Done

Administrative controls involve procedures and planning. They help reduce risk but rely on people following them correctly.

Examples include:

• safe work procedures
• training for working at heights
• access permits
• signage and hazard warnings
• maintenance schedules

These controls are important, but they should support physical safety systems, not replace them.

Level 5: PPE – The Last Line of Defence

Personal protective equipment is the lowest level of control.

In height safety, this includes:

• harnesses
• lanyards
• helmets
• protective gear

PPE doesn’t remove the hazard. It only reduces the consequences if something goes wrong.

It also depends on:

• correct use
• proper training
• ongoing inspection

That’s why it should always be treated as a backup, not the primary solution.

Applying the Hierarchy to Real Buildings

In practice, height safety is rarely solved with a single system. Most buildings require a combination of controls.

A typical approach might include:

• reducing unnecessary roof access
• improving access points
• installing walkways to define safe paths
• adding guardrails to remove edge risk
• using anchor systems where required
• supporting everything with clear procedures

The right solution depends on how the building is actually used.

If you want a breakdown of how this applies in real scenarios: Roof Access Safety: Practical Height Safety Solutions for Commercial Buildings

Why This Matters When Reviewing Safety Reports

Height safety reports often list multiple non-conformances without clear prioritisation. The Hierarchy of Control helps make sense of that.

Instead of trying to fix everything at once, it allows you to focus on:

• removing the highest risks first
• choosing controls that reduce reliance on human behaviour
• avoiding unnecessary or overly complex solutions

If you’re working through a report and need a clearer plan:

Final Thoughts

By starting with elimination and working down through substitution, engineering controls, administrative measures, and PPE, you can create systems that are safer, simpler, and more reliable.

For facilities managers, this framework provides a clear way to move from a list of safety issues to a practical plan that actually improves the building.

If you want help turning a report or site into a clear plan of action: