Demolishing or Modifying Existing Structures

From time to time contractors have to demolish existing structures, either completely or partially, to enable new structures to be built. This work is inherently dangerous, and if it’s not done correctly could result in the remaining structures or surrounding property being damaged, and even people getting injured or killed.

Usually, large demolition work must be done by licensed contractors, but often projects involve smaller demolition works which are tackled by less experienced people. In fact, sometimes contractors have to demolish newly completed work because the work was substandard of poor quality and didn’t meet the project specifications because the client changed their mind, or the designer made a mistake. Some of these demolitions are done with little forethought and planning, sometimes with inappropriate equipment, often done hurriedly so that impacts to the construction schedule are minimised.

To prevent accidents it’s important that certain precautions and steps are implemented before any demolition work begins. These include:

1. Ensure all service lines and pipes have been terminated. Live electric cables are dangerous. Damaged water pipes can flood the project, or possibly leak underground undetected. Ruptured gas pipes can lead to explosions.
2. Make sure that the right structures are demolished. For example; in 2016 the wrong house in Sydney Australia was demolished. The contractor arrived at what they thought was the correct address and proceeded to demolish the house, instead of the house next door which they were supposed to demolish. A very expensive and embarrassing mistake. It pays to always double check and also to ensure that there is adequate supervision in place.
3. Hazardous materials, such as asbestos, should be identified and where possible removed. Not only are these materials hazardous to work with but they can contaminate all of the demolished materials and parts of the construction site which can cause bigger problems and costs to clean up.
4. All permits and permissions must be in place. Many jurisdictions require demolition contractors to be licensed.
5. Check that there aren’t any restrictions – heritage structures can’t be demolished.
6. Ensure that items that are to be salvaged have been removed.
7. Protect the surrounding properties and structures from dust and debris.
8. Prepare a risk assessment and safe work procedures.
9. Have the right equipment and trained operators.
10. Barricade the areas where demolitions are happening and keep unauthorised people out of the area.
11. Clear demolished material as quickly as possible to make the area safe.
12. Plan the work so that demolitions are done in the correct sequence therefore equipment can safely reach parts that have to be demolished, and so that structures aren’t left standing which are unsupported or weakened; they could collapse in an uncontrolled manner on top of people, equipment or other structures.
13. Provide adequate warnings to those around the demolition work who could be impacted by the demolitions.
14. Ensure there is adequate dust suppression systems in place to minimise dust.
15. For large demolitions it is advisable to complete dilapidation surveys of the surrounding structures to record all existing cracks and defects. This will ensure that the demolition work can’t be blamed for damaging structures and buildings when the cracks were already pre-existing and weren’t a result of the demolitions.

Often existing structures have to be partly demolished and openings cut in them. In addition to the checks above it’s also necessary to:

1. Have an engineer check the structure to determine that the modifications won’t impact its structural integrity.
2. As directed by the engineer, install permanent structural supports and beams, and where necessary temporary props and bracing.
3. Not remove temporary props and supports until the replacement structures have attained sufficient strength and have been inspected by the engineer.
4. ...Continue Reading....

​This article was first published on the ClockShark website. To visit this website and continue reading the article click on the link above.
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