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How Much Does a Granny Flat Cost?

Granny flats, also known as Secondary Dwellings, have become increasingly popular to provide extra living space for family members, guests, or even as a rental property. However, before embarking on the construction of a granny flat, one of the primary considerations is the cost involved. 

The cost of a granny flat can vary significantly based on a variety of factors, including the size, materials used, and location. This article explores the various elements that impact the cost of building a granny flat, providing you with the insights you need to make informed decisions about this exciting addition to your property.

How Much Does it Cost to Build a Granny Flat?

The cost of building a granny flat can vary greatly depending on various factors such as the size, location, materials used, and the complexity of the design. In general, the cost to build a granny flat can range from $100,000 to $200,000 or more.

Here is a breakdown of some of the costs you can expect when building a granny flat:

Factors that Affect the Cost of a Granny Flat

1. Size

Generally, the larger the granny flat, the more materials and labor will be required to build it, which means a higher overall cost. Let’s assume that a basic, one-bedroom granny flat with a total floor area of 30 square meters and costs around $100,000 to build. 

If we were to increase the size of the granny flat to two bedrooms with a total floor area of 60 square meters, the cost could go up to around $130,000. This increase is because the required materials and labour increase considerably. It may be double the size, but it does not double in price as many items cost the same or similar regardless of the size.

2. Location

Other factors such as the cost of materials and labour, can vary depending on the location if the trades and suppliers have to travel longer distances to make deliveries or carry out works. 

Some areas may require special works to be carried out to meet flood requirements, bushfire requirements, acoustic requirements near noise roads or airports, high wind areas, coastal areas subject to sea spray or traffic control on busy roads, which can increase the overall cost of construction.

3. Design

More complex and modern granny flat designs will require more time and materials to build, which can increase the overall cost. Spacing is especially important as the flat design determines how much space is available and how it will be utilized within the structure. 

For example, an open floor plan with fewer walls and partitions may be less expensive to build than a design with many rooms and hallways. Additionally, a design that has features like additional garages, alfrescos, patios, large feature windows or doors all impact the cost to build a granny flat

4. Materials

The choice of materials and finishes used in the design can have a significant impact on the cost of the granny flat. For instance, high-end finishes such as hardwood floors, brickwork, and custom cabinetry will increase the cost compared to more economical options like laminate floors, tiles, cladding, and standard cabinetry. However, you can mix and match materials and finishes to create a unique and customized look that fits within your budget. 

Hardwood floors are an excellent choice for people who suffer from allergies, as they do not harbor dust, dander, or other allergens. Stone benchtops are highly durable and resistant to heat and scratches, making them a practical choice for kitchens and bathrooms. 

5. Site Preparation

If the site is difficult to access or has limited space for equipment and materials storage, the cost of site preparation will be higher. This is because additional labor and equipment will be required to maneuver around obstacles and work in tight spaces.

Moreover, if the soil is unstable or contains rock, additional excavation and grading work may be required. The type of foundation required for the granny flat can also affect the cost of site preparation. A standard concrete slab foundation is less expensive than a raised foundation, which can require additional time, preparation work and materials depending on the raised foundation type required.

6. Utilities

The cost of water, electricity, and gas is another significant expense to consider. If the granny flat is located in a remote area, the cost of installing utilities may be higher. And if the existing utilities at the site are insufficient to support the granny flat, upgrades or modifications may be necessary. 

These upgrades can include installing upgrading electrical boards or wiring in older dwelling, or adding a new septic system. Running stormwater to the street, if the existing stormwater is not working correctly. And remember, you also have to anticipate annual maintenance on heating and cooling systems, replacing water heaters or repairing leaky pipes.

7. Timeframe

The longer the project takes to complete, the more hours of labor are required, which add up to the overall cost of the project. Most builders offer fixed pricing so this should not be a concern and any time frame should be allowed for in their pricing. However if the building project is being financed through a loan, a longer construction timeframe can mean more months of interest payments. And less months of rental income if your intentions are to rent the granny flat.

Besides, the cost of materials fluctuate over time, so a longer construction timeframe may mean that materials become more expensive. You may even have to reorder materials or purchase additional supplies if the project is delayed due to unforeseen circumstances, this is only a concern if you do not get a fixed price contract.

Final Thoughts 

Remember, the figures mentioned above are rough estimates, prices can fluctuate with changes in the industry. It’s best to consult a professional builder or contractor to get a more accurate estimate based on your specific requirements and location. Smart Choice Granny Flats offers clear insight on the financial commitment of building a granny flat in Sydney. Instant online quotes are a available, Get a free quote today.