Protection Works

Building work may sometimes adversely affect adjoining properties.  Owners proposing to build have obligation under the Building Act 1993 (the Act) to protect adjoining property from potential damage. 

If building work is close to or adjacent to the adjoining property boundary, protection work may be required to ensure that the adjoining property is not affected.

Protection work provides protection from damage to the adjoining property.  This includes:

• Under-pinning of footings to buildings on adjoining property
• Retaining walls where site cutes have occurred
• Barriers to prevent material from falling on the roof or other part of an adjoining property

As a general rule for the majority of local residential sites, protection must be provided where a cut is deeper than the distance from the allotment boundary and where fill exceeds a gradient of 1:2 or otherwise where there is insufficient space available for drainage and batter.  Although this may be appropriate for the majority of cases it ignores the possibility that protection work may be required in other circumstances.  For example a deep footing system or site cuts in unstable soil may require considerable protection work.

Situations for unprotected embankments are indicated in the Table below:

On level sites, protection need not be provided where minor footings are placed adjacent to the allotment boundary, on the basis the existing foundation is being replaced by concrete as soon as practicable after excavation. Protection would not usually be required where the amount of fill/cutting does not exceed 200mm at the boundary of a vacant allotment and the fence incorporates a suitable plinth.

How to comply

Documentation of the proposed building works submitted with an application for a building permit is to include the following details:

• Location of buildings on the adjoining allotments.
• Site levels before and after excavations are undertaken.
• Determine if unprotected embankments are within the limitations of the above Table.
• If protection work is required the additional following details will apply.
• Design computations and structural details for construction of the proposed retaining wall.
• Forms 3 and 4 to be completed by the owner and affected adjoining owner/s.  Then copies provided to the Relevant Building Surveyor prior to issue of a Building Permit.
• Where existing buildings on an adjoining allotment are located in close proximity and may be affected by the proposed building works further enquiries must be made with the relevant building surveyor as other requirements may apply.

An alternative procedure is to provide dual certification for design of the retaining wall.  These generally may be from the same company, but must be two separate registered civil engineers.  Furthermore, the adjoining owner must be provided with copies of the dual certification and relevant documentation (e.g. retaining wall design).  In this case, it is not necessary for the Building Surveyor to be provided with evidence of notifying the adjoining owner, although if not provided, the Building Permit must include an appropriate condition.

Further information may be obtained from the staff at Building Issues or otherwise you may prefer to research the references below to gain a thorough understanding.

References
VBA Practice Note 20 – http://www.vba.vic.gov.au/__data/assets/pdf_file/0018/21078/PN-20-2006-Protection-Work-Process.pdf
BCA Volume 2 – Part 3.1.1
Building Regulations 2006 – Regulation 602, 603 and 605
Building Act 1993 – Part 7 (Section 84-101) Protection of Adjoining Property