Thinking about adding an extension to your home?
You’re not alone. Home extensions are one of the most popular forms of Australian residential construction right now. In fact renovations passed $48 billion. That’s a 13% increase on the previous year. Clearly there are plenty of families building up (and out), rather than moving on.
But here’s the catch…
The first mistake many homeowners make is choosing finishes and floor plans before consulting with professionals. This often leads to overspent budgets, delayed approvals, and stressful projects.
The good news? Getting the right team on board early can save you thousands.
Inside This Guide:
- Why the Right Team Matters
- The Key Professionals You Need to Consult First
- Where Stormwater Drainage Planning Fits In
- When to Bring Each Expert Onboard
Why Building the Right Team Matters
Home extensions are complex.
When you build an extension, you’re not just building a room. You are altering the dynamics of the property. How it waters, how it settles, how it deals with council and how it interacts with your existing house.
Fun fact: 73% cited unexpected costs as their biggest renovation roadblock. Most surprises arise from issues that should have been caught early — by hiring the right pros initially.
So it matters a lot more who the professionals you talk to initially are than what tiles you choose at the end.
The Structural Engineer: Your Load-Bearing Expert
Structural engineers should be one of the first calls you make.
Why ask? Because they determine if your existing home can structurally support the alterations you desire. This includes new walls, openings, second storey additions, and how it all connects back to the foundation.
They even factor into stormwater drainage planning. This is the homeowner’s worst enemy and the thing most homeowners don’t expect. When you put an addition onto your roof, add length to your slab or driveway… you are increasing your hard surface area on your block. Hard surface = runoff… and that water has to drain somewhere.
A competent engineer will ensure your stormwater drainage plans work with your footings, slab levels and retaining walls. When building in South Australia, early involvement with experienced Adelaide structural engineers can save you council knock-backs and costly redesigns.
Bring them in before you finalise your plans, not after.
The Building Designer or Architect
Next up is your designer.
Others do the opposite. They talk to builders initially and think they can then also design the extension. Builders can do this sort of thing alright — but only with very straightforward jobs. If you are changing structure or have a difficult site you want input from a designer/architect from day one.
A good building designer helps you with:
- Layouts that fit your budget and your block
- Meeting council setback rules
- Choosing materials that match your existing home
- Preparing plans that pass approval smoothly
They will also identify design problems later that would cost you more money…crooked roof lines, plumbing runs that will require costly relocation, or windows that are not energy code compliant.
The Licensed Builder
Once your plans are locked in… it’s time to talk to builders.
It’s tempting to just choose the lowest bid and get started. Resist that urge. Builders have vastly different specialties, and choosing the wrong builder for the task can be expensive.
When comparing builders, look for someone who:
- Has real experience with extensions (not just new builds)
- Can show you completed projects like yours
- Has a valid licence and full insurance
- Provides a clear, itemised quote
A good builder will also point out things your designer didn’t think of. They have seen it all before…and they will tell you what WILL and WON’T work.
The Hydraulic Consultant or Stormwater Engineer
Here’s a professional most homeowners have never heard of…
You will need one though. Submission requirements for most extensions include stormwater drainage planning. Councils need to know how you will manage rainwater running off your new roof, driveway or paved areas. Get this wrong and you could have your neighbours yard flooded… and find yourself in front of council.
Home renovation expenditure in South Australia has increased by more than 55% over the past five years. Councils are now receiving more renovation extension requests than ever before. They’re scrutinising stormwater drainage planning closely and rejecting applications with poorly thought out drainage plans.
A hydraulic consultant will design:
- On-site detention tanks (where required)
- Roof water and downpipe layouts
- Connection points to the council network
- Overland flow paths for heavy storms
It’s only a fraction of the overall project….but can make or break the approval process.
The Land Surveyor
Don’t skip this one.
A licensed surveyor verifies the precise boundaries, elevations and characteristics of your property. If your property isn’t surveyed, your designer is guessing. Guessing leads to encroachments, setbacks violations and easement problems.
Surveys generally range from several hundred dollars to a few thousand dollars. When you consider redesigning your extension because council turns you down, that is cheap insurance.
The Town Planner
You may also require a town planner if your extension is more than simple.
Planners know your local council’s zoning regulations, heritage overlays, character areas and neighbour consultation processes. They can shepherd your project through the approval process and handle any hurdles as they arise.
You may need a town planner if:
- Your property sits in a heritage or character zone
- You’re building close to boundaries
- Your council has complex zoning rules
- Your project needs a full development application
The Certifier or Building Surveyor
The certifier is the person who signs off that your build meets code.
They check your plans, inspect the job at milestones and issue the certificate of completion. It pays to talk to a certifier early, they can save you heaps of pain. They’ll let you know what will and won’t be approved before you get yourself into too much trouble with detailed plans and spending money.
Rounding Things Up
Extensions are one of the biggest investments most families ever make.
Happy homeowners are the ones who assembled the proper team from the get-go. Structural engineers that assist with stormwater drainage planning, certifiers that sign off the final product… you get the idea.
Here’s the short version:
- Talk to a structural engineer and designer before you finalise anything
- Get a proper land survey done early
- Involve a hydraulic consultant for stormwater drainage planning
- Choose an experienced builder with a background in extensions
- Use a town planner if your project is complex
