Building Up vs. Building Out: Which Extension Option is Right for You?

Expanding your home is an exciting opportunity to create more space, improve functionality, and enhance property value. However, choosing between second storey extensions and ground floor extensions requires careful consideration. The right option for your home depends on several factors, with each having unique benefits and considerations. In this article, we’ll consider the differences between building up vs building out, weigh the pros and cons and explain how XL Built can help you make the best decision for your needs.

The Pros and Cons of Building Up

Adding a double storey home extension is a popular choice for homeowners looking to maximise space without sacrificing their backyard. If your block size is limited or you want to preserve outdoor areas, a second-storey addition may be the best solution. Some advantages of second storey extensions in Melbourne include:

Preserving outdoor space – Keep your garden, patio or outdoor entertainment area intact.

Potential for better views – A second storey can offer scenic views and more natural light.

Increased home value – A well-designed second-storey extension can significantly boost resale value.

No need to move – If you love your location but need more space, adding another level can be a cost-effective alternative to relocating.

However, there are some factors to consider before committing to building up:

Some space downstairs will be repurposed – A staircase will need to be added, which means a small portion of the ground floor will be used to accommodate it.

Stairs aren’t for everyone – If you have family members with mobility concerns, a second storey might not be the most convenient option.

Some updates to the ground floor may be required – To support the new level, structural reinforcements may be needed, which could involve some renovation work downstairs.

The Pros and Cons of Building Out

For homeowners with ample land space, ground floor extensions in Melbourne provide a seamless way to expand. Extending outward allows for more design flexibility, especially for open-plan layouts. Some key benefits include:

Lower structural impact – No need to reinforce the foundation to support an additional level.

Easier accessibility – Ideal for families with young children or elderly members who prefer single-level living.

Potential for faster construction – Without the complexities of adding a second storey, timelines can often be shorter.

Despite these advantages, building out has some challenges:

Requires sufficient land space

May reduce backyard size and limit outdoor activities

Council regulations and setbacks can impact design possibilities

Cost Considerations: What’s the Best Value?

Understanding home extension costs in Melbourne is crucial when deciding between building up vs building out. Costs vary based on factors such as materials, labour and structural modifications. In general:

Foundation and structural costs – Building up can require reinforcing the existing structure, which may add costs. However, building out requires a new slab or sub-floor, and potentially expensive excavation or drainage work, especially on sloped blocks. If your home’s foundation is already strong, adding a second storey may be more cost-effective.

Plumbing, electrical, and HVAC extensions – Extending out may involve relocating underground services, which can be costly, while extending up typically requires running services vertically, which is often simpler.

Construction access and site logistics – Tight access can make building out expensive if excavation equipment can’t easily reach the site. Meanwhile, building up may require scaffolding and cranes, which can add costs depending on your home’s layout.

Permit and regulatory costs – Second-storey additions may have overlooking concerns, whereas ground-floor extensions may require setback and site coverage considerations. Council requirements can impact costs, so it’s worth checking what applies to your area.

According to REA; a second storey extension will normally cost around $1,800 to $15,000 per square metre depending on the “degree of difficulty” of the work required, with “degree of difficulty” refers to things like the types of rooms added and the quality of the finish.

Maximising Space and Functionality

Choosing the best extension type depends on your priorities. If maximising space efficiency is your goal, consider space-saving home extensions that incorporate clever storage solutions and open-plan layouts. Working with experienced professionals like XL Built ensures that your new extension is not only functional but also seamlessly integrated with your existing home.

Planning Permissions and Regulations

In Melbourne, both building up and building out require adherence to local council regulations and obtaining necessary permits. Factors such as zoning laws, height restrictions, heritage overlays, and setback requirements can influence your project's feasibility. Engaging with your local council early in the planning process ensures compliance and helps identify any constraints that could affect your renovation plans.

What Should I Expect During Construction?

Building out may allow you to remain in your home during construction, depending on the project's scope and the areas affected.

Building up often involves more invasive work, such as reinforcing the existing structure, which might necessitate temporary relocation.

Return on Investment

Well-executed renovations typically enhance property value. In Melbourne’s property market, additional bedrooms and bathrooms are highly sought after, potentially offering a higher return on investment. However, overcapitalising—investing more in the renovation than the property's value increase—should be avoided. Consulting with local real estate experts can provide insights into which renovations yield the best returns in your area.

Why You Should Consult a Qualified Builder

While researching options is a great starting point, consulting a qualified builder is essential to determine the most practical and cost-effective approach for your specific home. A builder can:

Assess your home's structure to confirm whether a second storey is feasible or if an extension is the better choice.

Provide accurate cost estimates tailored to your home’s existing condition and the scope of work.

Advise on planning permissions and regulations to ensure compliance with local council requirements.

Identify potential challenges early to mitigate unexpected costs and delays.

Recommend design options that align with your lifestyle and long-term property goals.

Choosing the right builder with experience in Melbourne home extensions ensures you receive expert guidance and a renovation plan that adds value and functionality to your home.

Why Choose XL Built for Your Home Extension?

At XL Built, we specialise in designing and delivering the best home extensions in Melbourne. Our expertise as home extension builders in Melbourne ensures that every extension is tailored to the unique needs of each client. Whether you're considering double storey home extension or expanding outward, our team provides:

Comprehensive planning and design consultations – We help you determine the best approach for your home and lifestyle.

Regulatory compliance and permit assistance – Our team ensures all home extension planning advice aligns with Melbourne's building codes.

High-quality craftsmanship and materials – We focus on durability and aesthetic appeal to enhance your home’s value.

Proprietary client portal – allowing our clients to monitor every stage of the build, including detailed financials, transparent communication and access to all documents.

XL Built holds an unlimited building licence, is registered with the Building Practitioner’s Board, and is a proud member of the HIA.

Both second storey extensions and ground floor extensions offer distinct advantages depending on your budget, space, and lifestyle. By carefully weighing the benefits of building up vs building out, you can make an informed decision that suits your needs. For expert guidance, trust XL Built—house renovation experts in Melbourne committed to bringing your dream extension to life.