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Demolition Work

What is Demolition Work?​

Demolition work means work to demolish or dismantle a structure, or part of a structure. This includes:

  • Complete building demolition
  • Partial demolition/strip-out
  • Structural alterations
  • Dismantling plant or structures

When Demolition is High-Risk Construction Work​

Demolition work is High-Risk Construction Work (HRCW) requiring a Safe Work Method Statement if it involves the demolition of an element of a structure that is load-bearing or otherwise related to the physical integrity of the structure.

Major Hazards​

Structural Collapse:

  • Uncontrolled or premature collapse
  • Workers trapped/crushed

Asbestos:

  • Most buildings pre-2004 contain asbestos
  • Disturbing asbestos releases deadly fibers

Falls from Height:

  • Working on structures being demolished
  • Floor/roof collapse

Underground Services:

  • Striking gas, electricity, water during demolition

Falling Objects/Materials:

  • Materials falling on workers or public below
  • Debris ejected during demolition

Hazardous Substances:

  • Lead paint, chemical residues
  • Dust (silica, general)

Plant and Equipment:

  • Excavators with hammers/shears
  • Elevated work platforms
  • Cranes

Before Demolition - Mandatory Requirements​

1. Asbestos Assessment (WHS Reg 443)​

[!warning] Never Demolish Without Asbestos Check Failure to identify asbestos before demolition is prohibited and extremely dangerous.

Requirements:

  • Obtain or prepare asbestos register for structure
  • If no register, presume asbestos present OR arrange inspection/sampling
  • If asbestos identified, arrange licensed removal BEFORE demolition
  • Provide asbestos information to all workers

See Asbestos for detailed guidance.

2. Structural Engineering Report​

Required for:

  • If as-built design documentation is not available
  • If structure has been damaged or weakened (e.g. by fire)
  • If plant is to be used on suspended floors
  • Complex structures
  • Where demolition method may affect stability

Report Must Cover:

  • Structural details and construction method
  • Sequence of demolition
  • Special precautions required
  • Method of preventing premature collapse

3. Service Disconnection​

Before Demolition:

  • Disconnect or isolate all services:
    • Electricity (confirm de-energized)
    • Gas (confirmed isolated by supplier)
    • Water
    • Telecommunications
    • Sewerage

Underground Services:

  • Locate using Dial Before You Dig
  • Protect or remove before demolition

Underground essential services exposed by potholing

4. Demolition Plan​

Plan Must Address:

  • Sequence of demolition (what comes down first, last)
  • Method (manual, mechanical, explosives)
  • Structural stability during demolition
  • Control of dust, noise, vibration
  • Waste management
  • Traffic management
  • Protection of public and adjacent properties
  • Emergency procedures

Methods of Demolition​

Manual (Hand) Demolition​

Process:

  • Top-down, piece-by-piece removal
  • Hand tools, small power tools

When Used:

  • Small structures
  • Where mechanical methods not suitable
  • Hazardous materials present (asbestos)
  • Adjacent structures must be protected

Hazards:

  • Falls from height
  • Manual handling
  • Dust exposure

Mechanical Demolition​

Equipment:

  • Excavators with:
    • Hydraulic breakers
    • Pulverizers
    • Shears
  • Wrecking balls (rare, high risk)

When Used:

  • Large structures
  • Faster than manual

Hazards:

  • Structural collapse
  • Plant rollover
  • Falling materials
  • Dust

Controls:

  • Competent operator
  • Safe operating distance
  • Exclusion zones
  • Water suppression for dust

Explosive Demolition​

Highly Specialized:

  • Licensed shot firers
  • Detailed engineering design
  • Large exclusion zones
  • Emergency services notification

Rarely Used: Except major structures in open areas.

Sequence of Demolition​

General Principle: Top Down

  • Remove roof first
  • Then top floors
  • Work down to ground
  • Basement last

Maintain Stability:

  • Remove non-structural elements first (windows, doors, fittings)
  • Leave structural supports until last
  • May require temporary bracing

Exceptions:

  • Mechanical demolition may work differently (push over intact)
  • Requires engineering assessment

Control Measures​

Structural Stability​

  • Follow engineering report
  • Install temporary supports if required
  • Monitor for unexpected movement/cracking
  • Establish exclusion zones (minimum 2 times building height for wire rope pulling/induced collapse)

Falls Prevention​

  • Edge protection on floors being demolished
  • Safety mesh under fragile materials
  • Scaffolding where needed
  • Fall arrest systems (if edge protection not practicable)

See Falls.

Falling Objects​

  • Barricades and exclusion zones
  • Chutes for dropping materials (enclosed)
  • Screens on scaffolding
  • Warning signs
  • Hard hat areas

Never Drop Materials: Use controlled lowering or enclosed chutes.

Dust Control​

  • Water suppression (continuous wetting)
  • Avoid dry sweeping or dry demolition
  • Enclose work areas where practicable
  • Respiratory protection for workers

See Silica Dust.

Public Protection​

  • Hoarding/fencing (minimum 1.8m high)
  • Gantries/awnings over footpaths
  • Traffic management
  • Warning signs
  • Security (prevent unauthorized entry)

Waste Management​

Segregate Waste:

  • Asbestos (special disposal)
  • Recyclables (concrete, metal, timber)
  • General waste
  • Hazardous waste (lead paint, chemicals)

Asbestos Waste: See Asbestos - requires licensed disposal.

Dust and Debris:

  • Prevent dust leaving site (water, barriers)
  • Clean roads daily
  • Cover trucks transporting waste

Practical Example​

Scenario: Demolishing 2-storey brick house (built 1970s)

Pre-Demolition​

1. Asbestos Assessment:

  • Building inspection conducted
  • Asbestos identified: roof (fibro cement), eaves, internal walls
  • Licensed asbestos removalist engaged
  • Asbestos removed (clearance certificate obtained)
  • Register updated

2. Services:

  • Electricity disconnected (verified)
  • Gas isolated by supplier
  • Water capped
  • Underground services located

3. Demolition Plan:

  • Method: Mechanical (excavator with pulverizer)
  • Sequence: Roof, walls, slab, footings
  • Dust control: Water sprays
  • Exclusion zone: 10m from structure
  • Public protection: 1.8m hoarding erected

During Demolition​

Controls:

  • SWMS reviewed with workers
  • Licensed excavator operator
  • Water tanker continuously wetting debris
  • Exclusion zone barricaded
  • Spotter monitoring for hazards
  • Hard hats, respirators (P2), hi-vis, boots
  • Waste segregated (brick to recycling, timber to bin)

Sequence:

  1. Non-structural: windows, doors, fixtures removed (manual)
  2. Roof sheeting and framing pulled down (excavator)
  3. Walls demolished section by section
  4. Slab broken up
  5. Footings removed
  6. Site leveled and cleaned

Result​

Demolition completed in 3 days, no injuries, asbestos safely removed beforehand, dust controlled, waste recycled.