Typically, the cost to add a second storey ranges from around $1,850 to $3,300 per square metre, though factors like complexity, materials, and property access can influence this amount.
For those considering this substantial home improvement, it’s important to account for additional expenses such as stair access and potential reinforcement of ground floor foundations.
Homeowners can start budgeting with estimates around $250,000 for a 100 square metre addition, with potential extra costs pushing the total higher.
Careful planning is essential to ensure the project aligns with your needs and financial capacity. Knowing the associated costs and requirements early on can help avoid surprises and make the process smoother.
Suggested Reading: Want to know about costs beyond a second storey? Check out Soho’s guide on house extension costs per sqm.
Planning Your Second Storey Addition
Adding a second storey to your home involves careful planning, understanding your current home structure, making critical design choices, selecting the right professionals, and ensuring all legal requirements are met.
Evaluating Current Home Structure
Assessing the current state of your home is crucial before undertaking a second storey addition. It begins with a detailed evaluation of your home’s foundation and structural integrity.
Engaging a structural engineer can help determine if your existing foundation can support the additional load.
This assessment will guide necessary reinforcements to your ground floor foundations, ensuring safety and stability for the new structure. Understanding these structural aspects can prevent costly mistakes and structural failures during construction.
Design Considerations

Design is a significant part of planning, tailored to suit not just aesthetic preferences but also functional requirements.
Collaborate with an experienced architect to draft a design that aligns with the existing structure and meets your lifestyle needs.
Consider room layout, window placement for natural light, and energy efficiency. Ensure the design proposal includes careful attention to building regulations and local council guidelines.
Effective design planning will enhance the home’s value and ensure a seamless integration of the new storey with the existing structure.
Choosing Your Builder and Architect
Selecting the right builder and architect is essential for the successful execution of your project. Look for professionals with extensive experience in second storey additions.
Verify credentials, past projects, and customer testimonials. It is advisable to obtain quotes from multiple builders to compare costs and services offered.
A good builder will coordinate with the architect to ensure the design is practical and cost-effective, while also adhering to building regulations. This partnership is critical for turning your vision into reality.
Approval and Legalities
Compliance with legal requirements is non-negotiable. Securing necessary council approval is a key step in this process. Submit detailed plans and structural reports to the local council for review.
Be aware of zoning laws, building regulations, and any potential restrictions specific to your locality.
Obtaining the necessary permits before commencing construction is essential to avoid legal complications.
Staying informed about these legalities ensures a smooth approval process and adherence to statutory norms throughout the construction phase.
Breaking Down the Costs of a Second Storey

Adding a second storey involves various significant costs including foundation and structural requirements, materials and labour, finishing, and potential contingencies.
Each of these elements can considerably impact your overall budget.
Foundation and Structural Requirements
Ensuring the foundation and structure can support an extra floor is essential. Often, this requires reinforcing the current framework and possibly extensive excavation.
Costs here can be substantial, typically around $2,500 per square metre. This includes formwork, concrete costs, and any necessary joists and beams.
These structural elements are the backbone of the second storey and demand attention to detail. Ignoring these can lead to unexpected costs later in the project.
Material and Labour Expenses
Material costs include anything from external cladding to internal finishes. High-quality materials naturally raise the overall expense, especially if opting for unique designs or premium finishes.
Labour expenses are equally crucial, covering skilled trades like carpenters, electricians, and plumbers. Contractors’ rates can vary widely depending on location and expertise.
According to estimates, material and labour for a second-storey addition could range from $1,850 to $15,000 per square metre.
Finishing and Customisation Costs

After the structural work, finishing the new space is another significant cost. This includes painting, tiling, and installing ceilings.
Customisation is where costs can skyrocket if adding features like a modern ensuite, kitchen or specialised rooms.
Finishes like premium flooring, high-end fixtures, and bespoke cabinetry will also increase your budget. High standards of customisation reflect personal taste, making home renovations both exciting and more expensive.
Potential Extra Costs and Contingencies
Always consider potential extra costs and contingencies. This could include architectural fees, wiring issues, or insurance adjustments.
Having a buffer in your budget for these unforeseen expenses is advisable. Contingency costs might also cover issues like weather delays or unexpected structural complications.
Planning for a buffer of 10-20% of the total budget is a practical approach. Remember, the cost guide suggests starting pricing from around $300,000, with potential increases depending on numerous variables.
Frequently Asked Questions

Adding a second storey to a home involves considering various factors influencing costs and comparing options like extending upwards versus outwards. Below are answers to common questions about the cost and considerations of adding a second storey.
What is the price range for constructing a second storey addition in Australia?
The cost of adding a second storey in Australia typically ranges from $1,850 to $3,300 per square metre. Material quality and structural work required to support the new level impact the price.
What factors contribute to the cost of building a second story on a house?
Key factors include the complexity of the design and the materials used. The price also varies based on whether the ground floor needs reinforcing. Additional costs may include work related to stair access and plumbing adjustments.
Can you suggest the most cost-effective approach to adding a second floor?
Choosing standard materials and designs can help keep costs lower. Consulting with experienced builders to minimise unexpected expenses and ensuring the ground floor is structurally ready can also save money. Regularly reviewing budgets and plans can prevent cost overruns.
How do the costs compare when opting for a second storey versus ground floor extension?
Extending upwards usually costs more per square metre due to structural requirements. However, it can be a space-efficient option for properties with limited land. Ground floor extensions are generally cheaper upfront but might consume more of the available land space.
What should one expect to pay for a second storey extension in capital cities like Sydney and Melbourne?
In Sydney and Melbourne, prices tend to be on the higher end of the range, often closer to $2,500 to $3,300 per square metre. Local labour rates and material costs contribute to these elevated prices.
Are there financial benefits to choosing a second storey addition over relocating?
Adding a second storey can be financially beneficial by avoiding the costs associated with moving, such as stamp duty, real estate agent fees, and removalist expenses. It also allows homeowners to stay in their preferred location while increasing their living space.
Looking For Your Next Home?
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