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Last edited 01 Sep 2021
The essence of safe demolition lies in efficient risk control, environmental management and careful planning. The CDM Regulations have provided a platform from which the industry should adopt best practice, demanding written plans of work for demolition even where a project is not notifiable.
- Allow sufficient time for planning the works.
- Procure an appropriate contractor (carry out safety and environmental audits).
- Provide sufficient information to a good standard.
 Pre-demolition information
- Asbestos demolition survey (to HSG264 standard).
- Utility information (showing disconnection locations if previously carried out).
- Structural hazards and risks (including relevant information such as condition, modifications, materials, etc).
- Hazardous materials and health hazards.
- Building regulations. Where demolition work is proposed, the owner must give the local authority building control department six weeks notice under Section 80 of the Building Act.
- Party Wall etc. Act notices.
- Desk studies indicating the historic use of buildings and land, contamination, mineshafts, wells and so on.
- Constraints to demolition imposed by the client or by the site conditions.
- Site finish required.
- Pre-construction information (CDM regulation 10).
Demolition requires notification to be submitted to the local authority to determine whether prior approval is required for the method of demolition where buildings are over 50 cubic metres, and for walls or gates.
 Demolition procedures
General demolition procedures include:
- Site compound and security set-up.
- Intrusive pre-demolition surveys (such as; asbestos survey for demolition, structural survey, hazardous materials surveys, etc).
- Isolation of utilities and removal of meters.
- Disconnection of utilities.
- Asbestos removal (in accordance with the Control of Asbestos Regulations).
- Soft strip (taking the structure back to construction materials including the removal of windows and door frames).
- Superstructure demolition with special measures as constraints demand, such as de-build or protection of adjacent structures.
- Processing of superstructure arisings.
- Slab and foundation demolition.
- Processing of arisings.
- Site finishes as required.
 Demolition methods
Demolition methods include:
Explosives allow rapid and complete demolition where other methods may be dangerous or slow. This requires extensive use of the police to enforce exclusion zones as well as pre- and post-demolition structural inspections for a substantial radius (in the order of quarter or half a mile). For more information, see Explosives.
 Hand demolition
These methods may be used for small-scale projects, or when demolition has to be carried out in a more sensitive manner due to site constraints such as; proximity to uncapped mineshafts, overhead utilities, pedestrian access, adjacent structures, or structural instability.
 Machine demolition
Common techniques include:
- Swinging ball: Heavy steel ball suspended from a crane jib.
- Wire rope: Can be used for demolishing parts of a structure.
- Pushing arm: A machine fitted with a hydraulic pushing arm. This is operationally limited by height, so a building should be reduced by other methods first.
 Other methods
Other methods that can be used include:
- Gas expansion burster: Used for 'bursting out' concrete in a prepared cavity.
- Hydraulic expansion burster: Similar to gas but uses wedges and pistons.
- Thermal reaction: Used together with wire pulling, this involves generating a thermal reaction which causes members to lose strength.
- Thermic lancing: Drilling or cutting silica materials by thermo-chemical action.
- Drilling and sawing: Used for cutting openings in reinforced concrete.
Buildings handed over for demolition generally contain hazardous waste, rubbish for landfill and recyclable material. Best practice use of site waste management plans for all demolition projects assists in ensuring the optimum recycling chains are in place. Clients can assist by handing over empty buildings and finding new uses for furniture and equipment.
Demolition produces products suitable for construction with the general rule that a recycled material can be considered a grade lower than its original state. So crushed structural concrete for example may be used as blinding, though with full treatment and a designed mix, it may be possible to achieve structural grade concrete. At present, it should be practical for a competent contractor to achieve 95% building recycling by mass, or even more for some structures.
The Coalition Agreement outlined the government’s commitment to increase housing supply, tackle the problems that rundown vacant properties cause and help support local economic growth from refurbishment and improvements. In a written ministerial statement of 10 May 2013, Official Report, Column 13WS, ministers committed to revising outdated guidance issued by the former Office of the Deputy Prime Minister in relation to demolition.
On 16 January 2015, The Rt Hon Eric Pickles MP, Secretary of State for Communities and Local Government, confirmed that the following pieces of guidance no longer reflect government policy and so were cancelled:
- Neighbourhood Renewal Assessment and Renewal Areas (DETR, 1997).
- Private Sector Renewal Strategies: A Good Practice Guide (DETR, 1997).
- Running and Sustaining Renewal Areas (DETR, 2000).
- Addressing the Needs of Run Down Private Sector Housing (ODPM, 2002).
- What Works? Reviewing the Evidence Base for Neighbourhood Renewal (ODPM, 2002).
- Housing Renewal Guidance – ODPM Circular 05/2003.
- Sustainable Communities: Building for the Future (ODPM, 2003).
- Assessing the Impacts of Spatial Interventions: Regeneration, Renewal and Regional Development - The 3Rs Guidance (ODPM, 2004).
- Neighbourhood Renewal Assessment guidance manual (ODPM, 2004).
 Related articles on Designing Buildings Wiki
- Achieve safety in demolition.
- Asbestos management.
- Building regulations.
- BREEAM Construction waste management.
- Conservation area.
- Construction dust.
- Crane regulations.
- Dangerous buildings.
- Deleterious materials.
- Demolition grapple market trends.
- Design life.
- Filtering facepieces.
- Health and Safety.
- How to conduct a pre-demolition audit.
- Listed building.
- National Federation of Demolition Contractors NFDC.
- Notify HSE.
- Party wall.
- Planning permission.
- Pre-construction information.
- Pre-demolition audit.
- Pre-demolition and pre-refurbishment audits.
- Principal contractor.
- Recyclable construction materials.
- Site clearance.
- Site waste management plan.
- Structure relocation.
- Structures at the end of their design life.
- Why demolition and infilling are blunt weapons in the management of historic structures.
 External references
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