Pour concrete over underground services without proper planning, and you’re setting yourself up for expensive problems. Whether it’s a driveway, industrial slab, or commercial car park, what’s underneath matters as much as what’s on top.
In Brisbane, with our expanding suburbs and ageing infrastructure, nearly every concrete pour deals with underground services. Power, water, sewer, NBN, gas – they’re all down there. And once you’ve poured tonnes of concrete over them, accessing these services becomes a nightmare.
The Expensive Mistake Everyone Makes
Here’s the scenario: You need a new driveway. The concreter rocks up, preps the ground, pours the concrete. Looks beautiful. Six months later, your sewer backs up. The plumber locates the problem – it’s right under the middle of your new driveway.
Now you’re paying to:
- Cut through your new concrete
- Fix the pipe
- Repair the concrete (which never looks quite right)
- Deal with the mess and disruption
All because nobody thought about service access before pouring.
What’s Really Under There?
Most properties have more underground services than owners realise:
Water mains – Usually running from the meter to the house. Poly pipe these days, but older homes might have galvanised or copper.
Sewer lines – From the house to the street connection. These need regular maintenance, especially with tree roots.
Stormwater drains – Often forgotten until they block. Run from downpipes to the street or absorption pits.
Electrical conduits – Underground power from the street or between buildings.
Gas lines – If you’re on mains gas, these run from the meter to appliances.
Telecommunications – Old Telstra cables, new NBN connections, sometimes multiple generations of cables.
Every single one might need access someday. Planning for that access before concreting saves massive headaches later.
The Service Location Dance
Before any major concrete pour, you need to know what’s underground. Dial Before You Dig gives you the official services, but that’s just the start. They show what the utilities know about – usually just their assets up to your property boundary.
What Dial Before You Dig won’t show:
- Private plumbing on your property
- Old services that were replaced but never removed
- Drainage installed by previous owners
- Electrical conduits between buildings
- That irrigation system from 1995
Professional service locators can find most of these using electromagnetic detection and ground-penetrating radar. It costs a few hundred dollars but compared to cutting up new concrete? Bargain.
Access Points: Your Future Self Will Thank You
Smart concreters build in access for underground services. This isn’t complicated or expensive – it just needs planning.
Inspection openings over sewer junctions let plumbers camera and clear pipes without breaking concrete. A simple PVC cap flush with the surface is all it takes.
Removable panels where services cluster. Instead of one solid pour, create sections that can be lifted if needed. Yes, it’s visible, but subtle design makes it architectural, not ugly.
Conduit sleeves for future services. Running power to a shed later? Water to a garden bed? Empty conduits during concrete pour cost dollars. Trenching through concrete later costs thousands.
Soft zones where you know services run but can’t install access. Pour thinner concrete or use pavers. Easier to break and repair if needed.
The Industrial Approach
Major infrastructure contractors understand this perfectly. When companies like Aqua Pipeline Contracting install large water and sewer mains, they design every structure with future maintenance in mind. Access chambers, valve pits, inspection points – everything’s planned for 50+ years of service life.
The same thinking, scaled down, works for any concrete project. Plan for maintenance from day one, not as an afterthought when something breaks.
Concrete Types and Service Protection
Not all concrete is equal when it comes to protecting underground services:
Standard concrete transmits load directly down. Heavy vehicles can crush pipes below, especially older clay or PVC pipes.
Reinforced slabs spread loads better, protecting services from point loads. Essential for driveways with heavy vehicle use.
Suspended slabs over service trenches eliminate load completely but cost more. Worth it over critical services.
Lower strength pours over services make future removal easier. Your concreter can adjust mix design for sacrificial sections.
The Pre-Pour Checklist
Before any concrete goes down:
- Locate all services – Official and unofficial
- Test critical services – That blocked drain will be harder to fix under concrete
- Install access points – Inspection openings, clean-outs, pull pits
- Document everything – Photos, measurements, depths
- Brief your concreter – Show them where services run
- Plan for the future – Empty conduits, expansion joints
When Things Go Wrong
Even with planning, sometimes you need to cut concrete to access services. When that happens:
Use service locators again – The original locations might have shifted or been recorded wrong.
Cut carefully – Diamond sawing minimises damage and vibration. Jackhammers near services are risky.
Go wider than needed – Trying to work through a tiny hole makes repairs harder and often damages more concrete.
Plan the repair – Matching existing concrete is hard. Consider decorative solutions that make the repair a feature.
Update documentation – Now you know exactly where that service is. Record it.
Special Considerations for Different Projects
Driveways need to handle vehicle loads without crushing services below. Thickness matters, especially over sewer and water lines. Consider the turning areas where wheels concentrate loads.
Pool surrounds often have multiple services – pool plumbing, electrical for pumps and lights, drainage. Plan access to equipment areas without destroying decorative concrete.
Shed slabs frequently become connection points for power and water. Run conduits under the slab during construction, not after.
Commercial projects have strict requirements for service access. Trade waste pits, grease traps, fire services all need regular inspection and maintenance. Cutting commercial grade concrete is even more expensive than residential.
The Money Side
Building in service access costs maybe 5-10% more during initial construction. Ignoring it and dealing with problems later typically costs:
- Service location: $500-1000
- Concrete cutting: $200-500 per square metre
- Service repairs: Variable, often $1000s
- Concrete repairs: $500-1000 per square metre
- Lost time and disruption: Priceless
Do the maths. Proper planning pays for itself if you need access even once.
Working with Your Concreter
Good concreters understand service access and will work with you. Bad ones just want to pour and run. Ask potential contractors:
- How do they handle underground services?
- Can they show examples of access provisions?
- Will they coordinate with service locators?
- How do they document what’s underground?
If they seem confused by these questions, find someone else.
The Bottom Line
Concrete’s permanent – that’s the whole point. But underground services need maintenance, repairs, and sometimes replacement. Smart concrete work plans for both realities.
Take the time to locate services, install access points, and document everything. Your future self (and your bank account) will thank you when that inevitable service problem happens. Because it’s not if you’ll need underground access – it’s when.
