If you’re building a Granny Flat on your existing property you probably have some idea of your land’s flooding risk – however, it’s vital to seek a professional assessment of flood risk prior to beginning construction of your flat. To determine if your property is flood-prone, you can take the following steps.
1. Request a section 10.7 (2) certificate and 10.7 (5) from your Local Council.
A section 10.7(2) and 10.7(5) certificate provides information on property zoning, relevant planning controls and any property constraints such as bushfire risk, land contamination and flooding risk.
2. Obtain local flood information.
If the section 10.7 (2) and 10.7(5) certificate shows your property is flood-prone, you’ll need to request flood information from your Local Council, if available, to gain a clearer picture of your property’s flood risk. This information can provide details on what type of flooding the area is prone to and the depth of floodwaters.
3. Obtain planning help from a Civil Engineer.
If your property is flood-prone, the information you’ve gathered from Council can be used by a Civil Engineer to provide advice on what flood measures need to be taken to protect your property.
There are three common types of flooding which can impact properties:
There are a range of important approvals you need to obtain before building a Granny Flat – or any building – including approvals associated with flood risk. General flood documents required for building approval include the following items.
This document supports the complying development application to confirm the proposal meets all relevant flood-related requirements for a complying development approval.
This document supports a development application, or complying development application, to confirm there are adequate measures in place to ensure safe evacuation from the property in case of a flood.
This document is required when your property is categorised as flood-prone and your Local Council do not have sufficient information on record to determine the effects of previous and/or future flood events.
In most cases, yes you will still be able to build a Granny Flat on your land even if it is a flood risk. However, you will need to engage the services of a a builder who can manage approvals in this zone and obtain proper documentation to ensure all precautions are taken to minimise your risk of property damage.
Assessing your flood risk is a compulsory part of any building project, however, if extra measures are needed to floodproof your property it can impact the cost of your Granny Flat build. The cost of floodproofing your Granny Flat will vary depending on the complexity of your needs and the number of professionals involved. Some common floodproofing factors which can increase the cost of a Granny Flat building project include the following services.
This is the management of the amount and quality of stormwater that is allowed to flow onto your land.
If the services of a Civil Engineer are required this will inevitably drive up the cost of your building project.
Raising your Granny Flat on stilts or pillars can help reduce the risk of flooding but will require extra materials, planning and labour which will carry additional costs.
If you’re building a Granny Flat in a flood-prone area the cost of insuring your property will be higher than that of one built outside of a high-risk flood area.
At the end of the day, taking steps to minimise the risk of flood damage to your Granny Flat prior to construction will cost far less than having to start over after losing your flat to flooding.
With an experienced in-house council planning and drafting team who take care of the approval process, you can rely on the APlus team to accompany you during the entire process. We offer a comprehensive, full-service Granny Flat building process which includes all floodproofing and certifications. Don’t leave anything to chance, with APlus you can ensure your Granny Flat is built in the best possible location and is as protected as it can be from natural flooding.