Unit 103- 00

​Demolition and destruction of buildings and structures 

​The main requirements in decommissioning 

Eventually most buildings will need to be demolished because they have come to the end of their viable life cycle or are in the way of a new development.​ 

Planning permission is not required if a building is less than 50 cubic metres, but is required for most other buildings. It is also required for unlisted buildings in a conservation area in Wales only.​ 
A detailed sequence of work needs to be drawn up before any demolishing can commence and must include: 

isolation of all services​ 
risk assessments and method statements. 

Environment impact and health and safety​

​Isolation of services: 
Gas, electricity, water supply and telecommunications all need to be isolated. Failure to do so can result in the release of toxic and explosive gases into the atmosphere, the risk of electrocution to operatives, and flooding leading to contamination of the waterways and land.​ 

 

Risk assessments and method statements:
These must include any specific risks and hazards associated with the removal and demolition of a property, cover the materials involved and preventing any debris and contamination leaving the location, so protecting the general public and the local environment from work undertaken.​ 

For further information visit the HSE website

​Methods of demolition

​Dismantling/Deconstruction 

 

This is the process of taking down a structure carefully and methodically, often in a reverse process of the one that was used to initially construct it. ​ 

 

It is mainly used if the building is of historical importance, and is to be rebuilt in another location, or is in a location that does not allow any other method of demolition to take place. 

 

Interior demolition​ 
Interior demolition is the taking apart of interior portions of a structure while preserving the exterior, usually in preparation for a renovation project. This usually includes the removal of walls, ceilings, pipes, etc.​ 

 

Selective demolition​ 
A selective demolition project involves the removal of specific interior or exterior portions of a building while protecting the remaining structure and nearby structures. 

 ​ 

Total demolition​ 
Total demolition is the demolition of an entire structure. 

Crane and wrecking ball 

Less widely used today as modern methods are more accurate and faster. 

Wrecking balls range from 1,000 to 12,000 pounds in weight and are made from forged steel (an alloy of carbon and iron).

They are round so they do not get trapped in a buildings structure when they are slammed into it. 
​
Like a giant sledgehammer or when dropped from a height by a crane.​

​Implosion

​Implosion uses a series of explosive's to destroy the buildings vertical supports, causing the building to collapse into itself. 

Implosion is most often used to bring down large structures, such as chimneys, Cooling towers, tower blocks, etc.

​Mechanical demolition

​Mechanical demolition uses a high-reach arm machine fitted with either a crusher, shears, hammer or bucket to break and remove sections of a building starting at the top and working down.

​Shears






Crusher








Bucket

​Stages involved in removing demolition waste

Planning: Ensures all permissions, plant, equipment policies and procedures are in place.

Site security: Protect the general public from work activities.

Isolation of services: Protect operatives and the environment.

Removal of hazardous waste: Protect operatives and the environment, including reduced land fill.

Architectural salvage: Removal of  specific items of value for reuse

On-site processing of aggregates: Can be reused on-site or shipped out ready processed.

Recycling metal waste: Reduced carbon footprint. 

Multiple Choice

Name the Demolition

• Implosion

• Destruction
• Demolition
• Renovation

Multiple Choice

Name the Demolition

• Demolition
• Renovation
• Destruction
• Wrecking Ball