How to Write a Risk Assessment for Demolition Work

Why demolition risk assessments catch people out

Demolition looks simple from the outside — knock it down, clear it away, move on. In practice it is one of the most hazard-dense activities on any construction site. Structures behave unpredictably, hidden materials cause serious harm, and the work changes hour by hour. A risk assessment written on a generic template the night before is almost useless.

This guide walks through what a proper demolition risk assessment needs to cover, how to structure it, and how to keep it relevant as the job progresses.

Start with the pre-demolition survey — every time

You cannot write a credible risk assessment for demolition work until you have surveyed the structure. This is not optional under CDM 2015 — it is a legal baseline. The survey should establish two things: structural condition and hazardous materials.

Structural condition

Find out how the building was constructed, what has been modified, and what is holding what up. Party walls, load-bearing elements, basements, voids, and any previous partial demolition all affect the sequence of work and the risk of unplanned collapse. Get a structural engineer involved if there is any doubt.

Hazardous materials

Asbestos is the obvious one — any building constructed or refurbished before 2000 is suspect. But also check for:

• Lead paint, particularly on older steel or windows
• Polychlorinated biphenyls (PCBs) in old electrical equipment
• Contaminated land or tanks if you are taking down structures near industrial use
• Radioactive sources in older industrial or laboratory buildings

If asbestos-containing materials are present, a licensed asbestos removal contractor must deal with them before demolition begins. Your risk assessment needs to reflect this sequence explicitly.

Identify the hazards specific to the job

Generic demolition hazard lists are a starting point, not a substitute for thinking. Walk the site and work through each phase of the planned demolition. Common hazards include:

• Unplanned structural collapse — the single biggest cause of demolition fatalities
• Falling materials — debris, masonry, fixings and glass
• Buried or overhead services — gas, electricity, water, telecoms
• Silica and construction dust — particularly from concrete, brick and block
• Noise and vibration from plant and breakers
• Working at height — especially during roof strip and floor removal
• Plant movement — excavators and high-reach machines operating close to workers and boundaries
• Adjacent structures — neighbours, party walls, live roads
• Fire and explosion — from residual gas, dust accumulation or hot works

For each hazard, record who is at risk: your own operatives, subcontractors, members of the public, occupants of adjacent buildings.

Apply the hierarchy of control — in order

The most common mistake in demolition risk assessments is jumping straight to PPE as the control measure. PPE is the last resort, not the plan. Work down the hierarchy properly:

1. Elimination — can you remove the hazard entirely? Strip out services and hazardous materials before structural demolition starts.
2. Substitution — can you use a safer method? Deconstruction by hand rather than mechanical demolition reduces collapse risk in tight spaces.
3. Engineering controls — propping and temporary works, exclusion zones, dust suppression with water, acoustic enclosures.
4. Administrative controls — safe working sequences, permit-to-work systems, briefings, restricted working hours near sensitive receptors.
5. PPE — hard hats, dust masks (correct RPF for the material), ear protection, safety boots, hi-vis, and eye protection as a minimum.

For each hazard you identified, work through this list and record what you are actually doing — not what you would ideally do in theory.

Assess likelihood and severity — then set a residual risk rating

Once controls are in place, score the residual risk. A simple 5×5 matrix (likelihood × severity) is enough for most jobs. What matters is being honest: if your controls are genuinely effective, the residual risk should drop. If it does not, you need more or better controls — not a lower score on paper.

Flag anything that remains medium or above as a point requiring review before that phase of work starts.

Document the demolition sequence

A demolition risk assessment is almost always accompanied by, or cross-referenced with, a method statement. The sequence matters enormously — taking out the wrong element in the wrong order is how structures collapse. Your documentation should show:

• The planned order of operations (top-down is usually the default for most structures)
• Where temporary works or propping is needed and when it is installed and removed
• Exclusion zones during each phase and how they are enforced
• Plant movements and working areas
• What triggers a work stoppage and who has authority to call it

Plan for change — demolition risks evolve

Unlike a static construction task, demolition changes the site every day. A wall that was stable on Monday may be suspect by Wednesday once the structure next to it has come down. Your risk assessment needs a review trigger built in:

• At the start of each new phase
• After any unplanned event (near miss, partial collapse, unexpected discovery)
• When weather conditions change significantly (wind affects stability; wet conditions affect ground bearing)
• When a new subcontractor starts on site

Record each review, who carried it out, and what if anything changed. This is your evidence of ongoing compliance.

CDM 2015 and the Principal Contractor's duties

On notifiable projects the Principal Contractor must ensure the risk assessment forms part of the Construction Phase Plan. For demolition specifically, HSE expects the plan to address the pre-demolition survey findings and the sequence of work. Even on smaller jobs where notification is not required, the same good practice applies and will be expected by any diligent client.

Putting it together without spending hours on paperwork

A thorough demolition risk assessment does not have to mean hours at a desk. Taking photos during your site walk — of structural concerns, hazardous materials, access constraints, adjacent properties — gives you a record of conditions that is hard to dispute and makes writing up much faster.

If you want to speed up the document itself, SiteSafePro lets you feed in those site photos alongside a typed description of the job and generates a structured risk assessment draft in seconds — one you can review, adjust, and sign off rather than build from scratch.

A quick checklist before you sign off

• Pre-demolition survey completed and findings recorded
• Asbestos survey result obtained and actioned
• All buried and overhead services identified and isolated or protected
• Hazards listed with who is affected
• Controls applied in hierarchy order — PPE is not the first answer
• Residual risk scored honestly
• Demolition sequence documented
• Review triggers defined and recorded
• Risk assessment briefed to all operatives before work starts
• Copy held on site and accessible

Demolition is unforgiving when things go wrong. A risk assessment that reflects the actual job — not a generic one pulled from a folder — is the difference between paperwork that protects people and paperwork that just fills a file.