NZS 3916 is the design and build sibling of NZS 3910. The structure is familiar, the roles are the ones you know from NZS 3910 (the Engineer under the 2013 edition; a Contract Administrator and an Independent Certifier under NZS 3916:2025, published late last year), and most of the administration runs the same way. The difference is in one sentence: the Contractor designs the thing as well as building it, and carries the risk that the design does what the Principal asked for.
For a council letting a $600,000 changing room or a $2M pontoon, that sentence is attractive. It is also where most of the trouble starts.
Where it earns its keep
Repeatable facilities. Toilet blocks, changing rooms, small pump stations, shelters. The contractor has built twenty of them, owns the details and knows what they cost. Asking a consultant to design one from scratch and then tender it buys you a bespoke answer to a solved problem.
Proprietary systems. Pontoons, gangways, modular buildings, retaining systems. The supplier’s engineer knows the product better than any independent designer will, and the warranty is only worth having if they designed it.
Time. Design and procurement overlap instead of running in series. On a project that must be open by summer, that can be the difference.
One accountable party. When the gangway does not fit the pontoon, there is no argument between designer and builder about whose drawing was wrong. That alone is worth a great deal to a small client team.
Where it bites on smaller projects
The Principal’s Requirements are the whole contract. Under NZS 3910 the drawings and specification say what you get. Under NZS 3916 the Principal’s Requirements do, and on small jobs they are often two pages written in a hurry. Everything you forgot to ask for, you will pay for as a variation or live without. Floor falls, fixture quality, accessibility compliance, vandal resistance, maintenance access, design life: if it is not written down, it is the contractor’s call.
Tendering a design costs the contractor money. Three contractors each producing a concept and a price for a $500,000 job is a lot of unpaid work for two of them. The good ones decline to tender, or price the risk in. Regional markets with two or three capable firms feel this most. A two-stage process, or a modest design fee for shortlisted tenderers, is often money well spent.
Design risk comes back if the brief is wrong. The contractor carries the risk that the design meets the Requirements, not the risk that the Requirements were right. If the ground investigation was the Principal’s and it missed the soft layer, or the brief specified the wrong tide level, that is the Principal’s problem, under this form as under any other. Design and build does not transfer the risks you created before the contract was signed.
Settle the ground and the services first. The works around the building are where small design and build jobs lose their money: minor earthworks, retaining, drainage, and the water, wastewater, power and telecommunications connections. Nobody prices these well from a two-page brief, so they land as provisional sums, contingencies or variations. Have the site surveyed, the ground investigated and the utility connection points, capacities and costs confirmed before you commit to the form, and put the results in the Principal’s Requirements. The contractor can then price the building it is good at, and you are not paying a design and build margin on a trench.
Consents. Who obtains the resource and building consents, and what happens when a condition changes the design, has to be decided up front. Leaving consent risk with a contractor who has no control over the council’s timetable produces either a fat contingency or a dispute.
Design review is still your job. The Engineer, or the Contract Administrator under the 2025 edition, reviews the contractor’s design, and that review does not relieve the contractor of responsibility. But it is the Principal’s last chance to catch a design that technically meets the Requirements and will still disappoint the community that uses it. Budget for a competent reviewer and give them time. On a small job this is often the first thing cut, and it is the wrong thing to cut.
Insurance. A contractor designing in-house, or through a subconsultant, needs professional indemnity cover that actually responds to design liability on this project. Ask for the certificate and read the exclusions before award, not after the defect appears.
Changing your mind is expensive. Under a traditional contract the Principal owns the design and can adjust it. Under design and build, every Principal-initiated change ripples through the contractor’s design, programme and price. Councillors and community boards need to understand that the brief is fixed at award.
Three questions before you choose it
- Can we write a complete brief? If the honest answer is that the stakeholders have not agreed what they want, use the design phase of a traditional process to find out, or run early contractor involvement first.
- Is there a market? Name three contractors who would tender it with a credible designer. If you cannot, the form will not save you.
- Who reviews the design, and when? If nobody on the client side will read the contractor’s drawings with care before they are built, do not pretend the Engineer’s review is a safety net.
How we run one
We have been the Engineer under NZS 3916 on small public facilities for a district council. The method is the same as on any contract we administer: which hat we are wearing on every instruction, the review record kept, decisions in writing with reasons. The difference is where the effort goes. On a design and build job, most of the Engineer’s value is delivered before the contractor breaks ground: a brief that says what the community actually needs, a procurement that gets real competition, and a design review that is done properly and on time.
If you are weighing the form for a project, tell us the scope, the budget and who else is already involved. We will say whether we think it fits, and what the brief would need to contain.