Building a Duplex. All you need to consider

Building a duplex in the Illawarra or Wollongong can be an exciting and rewarding project. A duplex can add significant value to your property, but it’s also daunting.

We asked Wollongong’s Multi-Award Winning, Duplex and Building experts at Grand Pacific Homes to share all, so you can consider if this is the right construction project for you.

Grand Pacific Homes are the 2023 Winner of ‘Best Duplex in NSW‘, at the prestigious HIA Awards. They won TWO awards for their Duplex development in Woonona which you can view here. The HIA celebrates excellence in the building industry at a state and national level and Grand Pacific Homes is now short-listed for the National Duplex award. This national recognition now positions them as the go-to local experts to have all your duplex questions answered!

As the Illawarra’s custom home build experts, Grand Pacific Homes can help with your construction, renovating and rebuilding enquiries, whatever stage of the project you are at. Contact the team here.

To help you get started on your duplex building project, here is what you need to consider:

I want to build a duplex. Where do I begin?

  • Property: Do you have a suitable property or do you need to purchase land? Is the property and street frontage large enough, is it on a slope or in a flame or flood zone? Will you knock down and rebuild? Can you build a second dwelling next to an existing house?
  • Purpose: Are you building for you to live in it or is it strictly an investment? Do you plan to rent or sell one or both sides? This answer will help define your requirements in terms of size, functionality, and aesthetics.
  • Budget: Be realistic about you finances – it’s the most common area where dreams can become a harsh reality. Determine how much you are comfortable to spend and an amount for contingency. If necessary, explore financing options or even talk to Grand Pacific Homes about a joint venture.
  • Design: For building projects, design is everything. Side by side mirror image dwellings joined by a central internal wall are not the only option. Consider a detached design where each side is completely different. One could be a larger dwelling in the front of the property with a smaller dwelling in the back, forming a battle axe. The options are endless and we can help you design a duplex to maximise every opportunity available on the site.

Can I build a duplex? What are the potential issues that I need to address?

Do your homework here as it can save a potential disappointment down the road if your local Council has any concerns.

  • Zoning: Duplexes are generally allowed in residential zones (R2) if the property has a 15 metre street frontage, but check the specific zoning requirements for your property. 
  • Drainage: Ideally the slope of your property drains to the street. Otherwise, Council requires a stormwater management plan for water runoff, flood mitigation, and connections to existing infrastructure. 
  • Title: Your duplex may be subject to a Torrens Title (ownership of a parcel of land) or Strata Title (ownership of a lot within a larger property), which have cost implications for duplicating or sharing services such as water, electricity, gas and telecommunications.
  • Constraints: Get a professional to assess your property for potential challenges including flood, bushfire, geotechnical, traffic, acoustic, heritage and acoustic issues.

An experienced and reputable building designer will guide you through this analysis in the early stages. Grand Pacific Homes offer complimentary assessments before commencing any custom design.

A good builder and design company should then arrange for required consultants and reports. This is important because it raises any issues, before then submitting the development application to Council.

Grand Pacific Homes have many years of successful experience assisting prospective duplex owners turn their dreams into reality.

How much is it likely to cost to build a Duplex?

The cost of building a duplex project in the Illawarra can vary widely depending on factors such as the size of the duplex, the quality of finishes, the complexity of the design, site conditions, and current market conditions.

It is crucial to consult with professionals to determine an accurate budget estimate for your specific project. While some builders may offer a ballpark amount based on a square meter rate, more accurate pricing can only be estimated once a design has been done, with a tender price typically based on Council approved plans.

Typically, building costs exclude land acquisition, design and documentation, consultants and energy efficiency reports, Council fees, utility and service connections, site costs, landscaping and subdivision registration which can bump up the price dramatically.

Grand Pacific Homes recognises that budgeting is the most crucial part of the project. They help you get the most accurate picture possible in terms of cost.  They also recommend that you plan for a contingency budget. It can help you to cover those building surprises that can arise sometimes.

How long does it take to build a Duplex and how long will the process take?

Timeframes will depend on a variety of factors, many of which can be beyond your control. Grand Pacific Homes recommend budgeting for 24 months from concept to completion of your duplex.

Assuming that you are ready to get underway, below is a rough guideline in terms of the time that each stage could take.

  • Design Phase (3-4 months)
  • Development Application (DA) Prep (3-4 months)
    • Consultant reports and detailed architectural drawings prepared
  • Development Assessment & Selections (3-6 months)
    • Lodge the development application to council or private certifier for approval
    • Materials and finishes selections by client
  • Construction Certificate (CC) Prep (3-4 months)
    • Prep construction plans compliant to development consent and building regulations
    • Organising insurances such as Home Warranty and Public Liability
    • Sign the contract that outlines the scope of work, payment schedule, and timeline
  • Build Phase (9-12 months)
    • At Grand Pacific Homes, we work to a 9 month timeframe, weather dependant
    • Includes inspections at various stages of construction to ensure compliance with regulations in order to obtain an Occupation Certificate (OC) to certify that the duplex is suitable for occupation.

As with a financial budget, we also suggest you put aside some time for contingency purposes. No two projects are the same, and things can happen that will challenge any project program (who would have thought that we would experience all of the rain and floods that we’ve had over the past few years?).

Remember, building a duplex is a complex undertaking, so it’s crucial to seek professional guidance and engage experienced experts to assist you throughout the process. The expert team at Grand Pacific Homes can help you with a complimentary consultation, through to design and into the construction of your duplex.

As award-winning Illawarra builders with nearly two decades of experience, Grand Pacific Homes know how important these projects are to you. Your success is their success.

If you want to know more and have all your duplex questions answered by their award-winning team, please get in touch with Marlowe Richards on (02) 4227 6405 or email [email protected]

With our thanks to Grand Pacific Homes for sharing their expertise and sponsoring this article – click here to visit their site and learn more.

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