What AS 4902 actually is

AS 4902-2000 is the "General conditions of contract for design and construct." It sits in the same suite as AS 4000-1997 and was built off it, which is why the two read alike. The difference is the model: AS 4902 is a single point of responsibility contract, where the contractor takes on both the design and the construction. It covers a few procurement routes: design and construct, design development and construct, and design novate and construct, where the principal's design consultant is novated across to the contractor.

Under AS 4000, the principal owns the design and hands you drawings to build to. Under AS 4902, the contractor is responsible for the design meeting the brief, and clause 2.2 has the contractor warrant that the completed works are fit for the purpose disclosed in the contract. That fitness-for-purpose obligation is a bigger step than the ordinary duty to work with reasonable care and skill.

AS 4000 vs AS 4902: the difference that matters

In one line: AS 4000 means you build to someone else's design; AS 4902 means the contractor, and often the chain below it, owns the design risk too. That single shift changes what you're on the hook for.

  • Design risk. AS 4000 leaves it with the principal. AS 4902 puts it on the contractor, who often pushes design elements down to subbies doing shop drawings, set-out or a "design portion."
  • Fitness for purpose. AS 4902 carries a warranty that the works suit the purpose stated in the contract, a higher bar than simply doing your work competently.
  • What "complete" means. On a D&C job you can be responsible for gaps between drawings, not just for building exactly what's drawn.
  • Novation. Your scope may sit under a design that has been novated across, so the design you rely on came from a consultant now working to the contractor rather than the principal.

The form you're actually handed: AS 4903

Subcontractors on a D&C project rarely sign AS 4902 itself. You sign AS 4903-2000, the "General conditions of subcontract for design and construct", the subcontract written to sit back-to-back with AS 4902. Its whole job is to cascade the head contract's obligations down to you so the main contractor stays consistent up and down the chain.

That back-to-back structure is the thing to watch. If the head contract carries a fitness-for-purpose warranty, a tight notice regime or a design obligation, AS 4903 is built to flow it down. The main contractor's contracts team will also amend it, tightening time bars, widening your design responsibility, or adding "buildability" wording that quietly moves more risk onto you. It's worth knowing the clauses that shift risk onto subcontractors before you sign.

What changes for you as a subcontractor

  • You may be carrying design risk you didn't price. Shop drawings, connections, set-out or a "design portion" can pull you into fitness-for-purpose territory.
  • Your notice and claims deadlines may be shorter and stricter, flowed down from the head contract. Check the delay notice time limits the day you sign, not the day something goes wrong.
  • The records you need are the same as any claim, but the bar is higher: you have to show your work met the brief, not just that you built what was drawn.
  • Insurance matters more. Design work can fall outside ordinary public liability cover and may need professional indemnity, so check what your policy actually covers before you take on design.

What to check before you sign

  1. Which form is it? Confirm whether you're on AS 4903 (D&C subcontract) or plain AS 4901, and read it against the head contract type. Our guide to AS 4901 and what to check before signing is a good starting point.
  2. What design are you responsible for? Get the design-portion, shop-drawing and set-out obligations in writing, and make sure they match what you actually priced.
  3. Is there a fitness-for-purpose warranty? Note where the contract says the works must suit a "stated" or "intended" purpose. The wording changes how far your obligation reaches.
  4. What are the notice time bars? Diary every deadline for delays, variations and EOT as soon as the job starts.
  5. Does your insurance cover design? Confirm professional indemnity cover for any design scope before work starts.
  6. What's been amended? Compare the subcontract against the standard AS 4903 and flag every change with your own adviser. Our free tools can help you spot the wording that shifts risk.

AS 4902 isn't more dangerous than AS 4000 on its own. It just moves the design risk, and a D&C subcontract is built to move a share of it onto you. Know which form you're signing, price the design you're actually taking on, and keep records that prove your work met the brief. For the wider picture, start with our guide to the standard contract forms subcontractors get handed.