Demolition Overview
Demolition is one of the highest-risk construction activities. It involves dismantling structures that may be unstable, contain hazardous materials, or present unique engineering challenges. Proper planning is not optional—it's essential.
Why Demolition is High Risk
- Structural instability—buildings may collapse unpredictably
- Presence of asbestos in most pre-2000 buildings
- Hidden hazards (services, voids, materials)
- Working at height during dismantling
- Heavy plant and machinery in close proximity
- Dust, noise, and vibration exposure
- Falling materials and debris
Under CDM 2015, demolition work must be planned and carried out only under the supervision of a competent person. This guide covers the key requirements and best practices for safe demolition.
Legal Requirements
CDM 2015 Regulation 22
"The demolition or dismantling of a structure, or part of a structure, shall be planned and carried out in such a manner as to prevent danger or, where it is not practicable to prevent it, to reduce danger to as low a level as is reasonably practicable."
CDM 2015 Regulation 22(2)
Demolition work must be carried out only under the supervision of a competent person. This person must have adequate training, knowledge, and experience in demolition operations.
BS 6187:2011
The British Standard code of practice for demolition. While not legally binding, it represents industry best practice and is often referenced in contracts. Following BS 6187 helps demonstrate compliance with CDM.
Control of Asbestos Regulations 2012
Before any demolition, a refurbishment and demolition (R&D) asbestos survey must be completed. Asbestos-containing materials must be removed before demolition can begin.
Demolition Planning
Demolition planning is fundamental to safe operations. A demolition method statement must be prepared before work begins, detailing how the work will be carried out safely.
Method Statement Contents
Planning Sequence
Information Gathering
Obtain drawings, structural information, asbestos surveys, service records
Site Survey
Physical inspection, structural assessment, hazard identification
Method Selection
Choose appropriate demolition method(s) based on survey findings
Method Statement Preparation
Document the planned sequence, methods, and safety measures
Review and Approval
Independent review, client approval, notification where required
Structural Engineer Input
For complex structures, input from a structural engineer is essential. They can advise on load paths, temporary support requirements, and the sequence in which elements can be safely removed.
Pre-Demolition Surveys
Comprehensive surveys are essential before any demolition work. Without proper surveys, hidden hazards can cause serious injuries or fatalities.
Asbestos Survey (R&D)
A Refurbishment and Demolition survey is legally required before demolition. This is more intrusive than a management survey and involves accessing hidden areas.
Required by: Control of Asbestos Regulations 2012
Structural Survey
Assessment of the structure's condition, load-bearing elements, any damage or deterioration, and how the building will behave during demolition.
Utility Services Survey
Identification of all utility services (gas, electric, water, telecoms, drainage). Must be isolated and disconnected before demolition.
Hazardous Materials Survey
Beyond asbestos: lead paint, PCBs in electrical equipment, radioactive sources (smoke detectors), biological hazards (pigeon guano, needles).
Environmental Survey
Protected species (bats, nesting birds), ground contamination, flood risk, proximity to watercourses, neighbours.
Demolition Methods
The demolition method depends on the structure type, location, constraints, and adjacent hazards. Often, multiple methods are combined.
Progressive Demolition (Top-Down)
The most common method. Structure is demolished from top to bottom using excavators with attachments (shears, crushers, breakers).
Best for: Multi-storey buildings, controlled environments
Deliberate Controlled Collapse
Explosives or pre-weakening to bring a structure down in a controlled manner. Requires specialist contractors and extensive planning.
Best for: Large structures, open sites with clear exclusion zones
Deconstruction (Piece-Small)
Manual dismantling, often in reverse order of construction. Allows maximum material recovery and reuse. Labour-intensive.
Best for: Sensitive locations, material recovery, internal fit-out strip
Wire/Diamond Cutting
Precision cutting of concrete or steel. Used where vibration must be minimised or for creating openings in retained structures.
Best for: Partial demolition, low vibration requirements, precision work
Wrecking Ball
Traditional method now less common. A heavy ball on a crane is swung into the structure. Requires large exclusion zones.
Best for: Large industrial structures with clear surroundings
Asbestos Considerations
Critical Rule
All asbestos-containing materials (ACMs) must be removed BEFORE demolition begins. Demolition must not proceed until asbestos removal is complete and the site has been re-inspected and cleared.
Any building constructed or refurbished before 2000 may contain asbestos. Common locations include:
Common ACM Locations
- Asbestos insulating board (AIB)
- Lagging on pipes and boilers
- Cement sheets (roofing, cladding)
- Floor tiles and adhesives
- Sprayed coatings
- Textured coatings (Artex)
Removal Requirements
- Licensed contractor for licensable work
- Plan of work (POW) prepared
- 14-day notification to HSE
- Enclosures and controls
- 4-stage clearance procedure
- Certificate of reoccupation
Unexpected Finds
If suspected ACMs are found during demolition, work must stop immediately. The area must be evacuated, secured, and the material sampled by a UKAS accredited laboratory before work can continue.
Key Hazards
Premature Collapse
Structure collapsing before or not as planned. Can be caused by underestimating instability or incorrect sequence.
Control: Structural assessment, temporary support, correct sequence, competent supervision
Falls from Height
Working on unstable structures, unprotected edges, or unsuitable access.
Control: Edge protection, MEWPs, safety harnesses, stable working platforms
Falling Materials
Debris falling from above, striking workers or public.
Control: Exclusion zones, catch fans, covered walkways, hard barriers
Dust and Silica
High dust levels from concrete, brick, and other materials. Silica is a particular risk.
Control: Water suppression, extraction, RPE, health surveillance
Live Services
Contact with gas, electricity, or other utilities not properly isolated.
Control: Service drawings, isolation verification, permit to work, CAT and Genny
Plant/Pedestrian Interface
Excavators and other plant working in proximity to operatives.
Control: Exclusion zones, banksmen, stop/start protocols, segregation
Competence Requirements
CDM 2015 requires demolition to be supervised by a competent person. The NFDC operates a training and certification scheme for the industry.
Key Roles
Demolition Supervisor
Competent person with overall responsibility for demolition operations. Should hold CCDO or equivalent. Named on the method statement.
Demolition Operatives
Should hold CCDO (Certificate of Competence Demolition Operatives) or be working towards it under supervision.
Plant Operators
CPCS/NPORS with relevant categories. High-reach demolition requires specific endorsements.
NFDC Membership
The National Federation of Demolition Contractors provides a framework for contractor competence. Many clients and principal contractors require NFDC membership or equivalent for demolition works.
Soft Strip Operations
Soft strip is the removal of internal fit-out, fixtures, and fittings before structural demolition begins. It's often carried out by different contractors and presents its own hazards.
Soft Strip Scope Typically Includes
- Ceiling tiles and suspended ceilings
- Internal partitions
- Floor coverings
- Mechanical and electrical services
- Sanitary ware
- Kitchen and catering equipment
- IT and communications cabling
- Furniture and loose items
- External cladding (sometimes)
Soft Strip Hazards
Don't underestimate soft strip risks. Asbestos may be hidden in ceilings and walls. Removing services without proper isolation is dangerous. Manual handling of heavy items and working at height are common. A RAMS specific to soft strip is essential.
Frequently Asked Questions
Does all demolition need to be notified?
Demolition work that is part of a notifiable project requires F10 notification. Additionally, if the work will exceed the 500 person-days threshold or 30 days with 20+ workers, notification is required.
Who writes the demolition method statement?
The demolition contractor, with input from a structural engineer where appropriate. It must be reviewed and approved before work starts. The principal contractor should review as part of construction phase plan.
Can I do my own demolition?
Small-scale demolition may be done by general contractors with appropriate competence. However, structural demolition should be carried out by specialist demolition contractors with the necessary experience and insurance.
What if we find unexpected hazards during demolition?
Stop work, make safe, and reassess. The method statement should be updated to address the new hazard. For asbestos finds, specific procedures apply under the Control of Asbestos Regulations.
How close can demolition plant work to retained structures?
This depends on the method, structure, and ground conditions. The method statement should define exclusion zones. A structural engineer may need to assess the impact of vibration on adjacent buildings.
Create Demolition RAMS
Need a RAMS for demolition work? DocGen's AI generates comprehensive risk assessments covering method statements, hazard controls, and safe systems of work for demolition operations.
Generate Demolition RAMS