The Split-Contract Problem

Subdivision civil works - pavement, kerb and gutter, drainage, final seal - are frequently split across multiple contractors in an attempt to achieve best price on each component. The earthworks contractor finishes, the kerb contractor comes in, the asphalt contractor follows, and a line marking subcontractor finishes the job.

In theory, each specialist optimises their component. In practice, the coordination gaps between them create defects, delays, and disputes that routinely cost more to resolve than the savings achieved by splitting the contract.

Where the Problems Appear

Interface Between Sub-Base and Kerb

The relationship between the compacted sub-base level and the kerb invert is critical. If the kerb contractor sets profiles independently of the base compaction contractor, you end up with drainage that doesn't fall correctly - water pools in gutters, backs up at low points, and finds its way under the asphalt. This is an extremely common problem in split-contract subdivisions and one that's expensive to remediate after the road is sealed.

Compaction Responsibility

When the earthworks contractor and the pavement contractor are separate entities, compaction responsibility at the handover point is frequently disputed. The asphalt contractor discovers soft spots or density failures after they've mobilised. Who repairs them - and at whose cost - becomes a project dispute rather than a straightforward quality control issue handled by one contractor.

Programme Compression

Each contractor runs their own programme. The kerb contractor can't start until the earthworks are complete and inspected. The asphalt contractor can't start until the kerb is cured. Each handover introduces a programme buffer. A project that could be delivered in 10 weeks under a single contract routinely takes 16 to 18 weeks under a split arrangement.

What Single-Contract Delivery Looks Like in Practice

When one contractor takes responsibility for the full scope - earthworks, sub-base, kerb and gutter, drainage structures, asphalt, final seal, and line marking - the coordination issues disappear because there's one party responsible for the outcome.

The sub-base level and the kerb profiles are designed together. Compaction testing is continuous, not a handover dispute. Drainage is designed and built by the same team who understands the relationship between all the elements. Defects have one responsible party, which means they get fixed, not argued about.

What to Look for in a Single Civil Contractor

Not every contractor who says they can handle the full scope actually can. Look for:

  • Owned plant, not hired: A contractor who owns excavators, pavers, rollers, and line-marking equipment controls their programme. A contractor who hires equipment is at the mercy of availability.
  • Experience across all trades: Ask for examples of projects where they delivered earthworks, kerb, drainage, and asphalt under one contract. Ask about the drainage design approach specifically.
  • Work built to RMS specification: Subdivision roads in NSW are ultimately dedicated to council. Council engineers expect RMS-standard construction. A contractor who does not build to that specification may deliver work that fails council inspection.
  • References from developers: Not just property managers or homeowners - developers who have run a full subdivision civil contract through one contractor and can speak to the coordination and programme outcome.

Our Approach

Brisbane Water Bitumen has been delivering complete subdivision civil packages on the Central Coast for over 15 years. Our own Komatsu and Caterpillar plant handles earthworks and sub-base. Our own paving and compaction equipment handles asphalt. We carry out kerb, drainage, and line marking under the same contract.

Every project has one contact, one programme, and one point of accountability from ground-break to council handover. If you're planning a subdivision on the Central Coast and want a straight conversation about scope and cost, we're happy to meet on site.