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AS 4902 design and construct contracts: what the form says and how it is usually amended

AS 4902-2000 is the design and construct sibling of AS 4000. The clause structure is largely the same, with one large addition: the contractor takes responsibility for design as well as construction. For a subcontractor that matters more than it sounds, because design risk does not stay with the builder. It is pushed down to the trades whose work it touches, often to trades who priced install only. The form is copyright Standards Australia, so this page describes it rather than reproducing it.

What the drafting says

What it is
Design and construct head contract, published by Standards Australia in 2000. Its subcontract companion is AS 4903.
Design responsibility
Sits with the contractor, who develops the principal's preliminary design to meet the stated project requirements.
Design warranties
Included, the contractor warrants the design and the finished works. Whether the works must be fit for a stated purpose is exactly the wording principals strengthen by amendment.
Consultants
Can be novated, the principal's designers may be transferred to the contractor, who then carries responsibility for their work.
Payment, notices, time
Same structure as AS 4000, 14 days to certify and 7 to pay, 28 days for notices, and a notice clause that does not bar late claims until it is amended.
Termination for convenience
Not in the standard form, added by special condition, as with AS 4000.

Figures read from publicly published documents analysed in the Australian Subcontract Index corpus, August 2026.

How it compares

The amendment pattern is the same one the Index records across subcontracts: notice clauses converted to absolute bars, set-off without notice, termination for convenience added.

The design and construct twist is a fourth pattern: design warranties widened, then passed down word for word to subcontractors whose scope and price never included design.

What to do about it

Match the warranty to what you priced
If you quoted install only, or supply and install to someone else's drawings, strike design warranties and fitness for purpose wording from your subcontract, or limit them to the parts you actually design. One sentence in the scope settles it: "The Subcontractor has no design responsibility."
Check your insurance before you accept design risk
A design warranty usually needs professional indemnity insurance behind it. If you do not hold it, you are carrying an uninsured liability. That is a reason builders accept the deletion when asked.
Ask for the project requirements document
Under a design and construct head contract the builder is measured against the principal's project requirements. If your work has to meet them, you need them in your contract documents, not referred to in passing.
The version you were handed is not the pattern. It's a specific document.
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Common questions

What is AS 4902?

AS 4902-2000 is the Australian Standard general conditions of contract for design and construct projects. The contractor is responsible for both design and construction, and the contract is administered by a Superintendent.

How do you draft an AS 4902 contract?

You do not rewrite the form; you buy it from Standards Australia and build around it. An AS 4902 contract is assembled from four parts. The general conditions are the printed form and stay as published. Annexure Part A is where the project particulars go: the principal and contractor, the date for practical completion, the liquidated damages rate, security and retention, the defects liability period, the insurance limits and the superintendent. Annexure Part B (or a separate schedule of special conditions) lists every amendment to the general conditions by clause number, and this is where the risk moves. Then the contract documents are scheduled: the principal's project requirements, the preliminary design, the tender and any drawings, in an order of precedence. A drafter working for a principal spends most of the effort in Part B; a trade reading one should spend most of theirs there too.

How are AS 4902 contracts usually amended?

The common amendments strengthen the design warranties, convert notice requirements into time bars, delete the Superintendent's discretion to extend time, add termination for convenience and widen set-off. The annexure then fills in the project figures: security, liquidated damages and the defects period.

Which subcontract goes with AS 4902?

AS 4903-2000 is the companion subcontract. In practice many builders use their own template instead and copy the design obligations across.

I only install. Can a design and construct subcontract make me liable for design?

It can if you sign it unamended. Liability follows the words, not the quote. Have the scope state that you carry no design responsibility, and have the design warranties removed or limited before signing.

Keep reading

General information for Australian subcontractors, not legal advice. Patterns describe publicly published documents analysed in the Index corpus, and standard forms are described from their published, unamended editions; the document you are handed governs, and only a reading of that specific document (or advice on it) can tell you your position. Written by Mat Kennedy at The Construction Contracts Co.