Landslip during building
Buying your first block of land to build your dream house on is exciting, however there are a few factors to consider prior to purchasing your block of land particularly with regards to landslip and how this may affect your build. It is not only the landslip during building you need to be concerned about but also the long term measures that may need to be put in place to ensure your home will stay put.
What is landslip?
Landslip can be described as movement of soil and/or rock down a slope. There are varying degrees of landslip. For example, landslip speeds can range from slow soil creep type movement or very rapid forms of landslip which can ultimately engulf a structure in a matter of minutes. It is important to understand if your land is impacted by landslip and how this will impact your ability to build in the future.
What can you do if your block is declared a landslip area?
There are resources available to help you determine if your land is within a landslip area. The Land Information System Tasmania also known as the List is a great resource to provide free land information whereby you can check if your block of land is likely to be affected by landslip. If your block has been declared landslip you will need to engage with a geotechnical engineer who will be able to conduct a landslip report. A geotechnical engineer will be able to assess the land and soil type to determine if there is adequate strength to support a dwelling and determine any other factors which may impact your ability to build based on the land assessment. There are two types of landslip, landslip A and landslip B areas. Landslip A areas are more unstable than landslip B areas. There are building provisions to follow regarding landslip areas covered in part 1 division 10 of the Building Act 2000 and part 2 division 1 of the Building Regulations 2004.
Building in landslip A area
It is important to note that if you have purchased land in a landslip A area that a person must not erect, alter, or add to a building in a landslip A area. However, there may be the possibility for an exemption whereby the Minister for Justice and Workplace Relations on the recommendation of a council general manager may permit a person to build a shed or one storey dwelling with a total floor area not greater than 25 square metres. You will likely need a certificate of compliance from a building surveyor, planning approval and your recommendation letter for the Minister. A comprehensive investigation will need to be undertaken to ensure all the requirements are met. You will also need to consider any additional costs for the build and assessments to ensure all minimum building requirements are met. –
Building in a landslip B area
If you have purchased land in a landslip B area and you are looking to construct or alter a building larger than 200 square metres a council permit authority may grant a permission to erect, alter, or add to a building in a landslip B area if a qualified engineer can provide you with a certificate demonstrating that the proposed building or alterations will not affect the land stability, is structurally sound and that the works can be carried out safely. In addition, it is likely that a building surveyor will need to issue a certificate of compliance for the pipes, sewage and stormwater for compliance. Normal council building and plumbing permit processes will also apply.
Designing a home in a landslip area
If the geotechnical engineer has deemed your land acceptable to build on based on their detailed report, your preferred building designer can begin designing your home. There may be some unavoidable design aspects which you may be required to include to minimize risk or damage to your dwelling due to landslip. It is important to consider any additional costs in your contingency. Your chosen building designer will be able to design your building based on the report and assessment of the geotechnical engineer and they will also be able to guide you through the regulations surrounding landslip during the design process.
We hope you consider all the necessary factors before purchasing a home or block of land particularly with regards to landslip. Every block is different so if you discover landslip on your block it is important to understand that while there are protocols and regulations surrounding landslip in Tasmania each site is unique and requires its own plan on how to tackle the situation. In addition, it is important to note that even if your block is not currently listed in a landslip A or a Landslip B area does not mean that your block does not contain landslip, if you would like more information about checking for landslip on your block contact us.
There are also additional resources available to you which show the statewide Landslide planning map in Tasmania which was developed by the department of premier and cabinet. The landslide planning map shows the position of hazard bands relative to properties. These hazard bands can be viewed on The List website and show the five categorized landslide hazard bands indicating susceptibility of a landslide. The 5 hazard bands are broken down into acceptable band, low band, medium band, medium active band, high band. For further explanation of each of these hazard bands please view here.
Need assistance to help you establish if your block is prone to landslip contact us