Standard contracts for major construction projects in Norway

NS 8408 and NS 8418 are two new standard contracts for major design-and-build construction projects in Norway, published late 2025. These standards bring a noticeably tighter approach to risk allocation, variations and dispute avoidance. This article sets out what has changed when these standards apply instead of the well-known NS 8407, and which provisions deserve your closest attention before you sign.

What are NS 8408 and NS 8418?

NS 8408 is used where the main contractor takes on all, or a substantial share, of both the design and the execution of a construction project on behalf of the employer – in other words, a design-and-build arrangement. NS 8418 is its subcontract counterpart, governing the relationship between the main contractor and a design-and-build subcontractor once the head contract has been let under NS 8408.

Both standards are reserved for projects where the sheer scale, complexity or organization of the works calls for a genuinely robust system of project governance and change management. Where that need doesn't exist, the established NS 8407 (main contract) and NS 8417 (subcontract) remain the better fit – and, for most projects entering the Norwegian market, that will still be the case.

Why does Norway need another set of standard contracts?

Norway has seen a wave of major infrastructure schemes procured on a design-and-build basis in recent years, yet the market never had a standard contract genuinely built for projects of this size and complexity. NS 8407 serves most design-and-build projects perfectly well, but it was never intended to carry the weight of governance and change control that the very largest schemes demand.

Faced with that gap, some parties in the industry had started looking instead to the Norwegian Total Contract (NTK), the standard long used in the offshore petroleum sector, which has for years featured a far more granular system for project governance and variations. NS 8408 and NS 8418 draw clearly on that experience, while keeping the underlying architecture of NS 8407. As it happens, NTK itself was also updated – to NTK25 – towards the end of 2025, so both contracts have effectively been refreshed at the same time.

Also read: Norwegian construction law - key differences for foreign contractors

When should you use NS 8408 and NS 8418 instead of NS 8407 and NS 8417?

Use NS 8408 and NS 8418 when your project is large enough, and likely to generate enough variations along the way, that you need a formalized, end-to-end governance model from day one. That tends to be the case on major road, rail and tunneling schemes, where ground conditions are uncertain, interfaces between parties are numerous, and the program leaves little room for slippage. For projects of that scale, NS 8408 and NS 8418 offer a framework that is genuinely built for the realities on the ground, in a way NS 8407 and NS 8417 are not.

If your project is more modest in scale, NS 8407 and NS 8417 will usually still serve you better. The heavier governance machinery in the new standards comes with an administrative cost, and that cost is only worth paying when the project genuinely requires it – something worth bearing in mind if you are new to the Norwegian market and weighing up your contracting options.

Also read: Construction contract types overview

What has changed in NS 8408 and NS 8418?

The single biggest shift is that almost everything capable of affecting price and program must now travel through one route only: The variation order. Even claims arising from the employer's own failure to cooperate must be pursued by the contractor as a variation order claim – a marked departure from the position under NS 8407 today. Beyond that, a handful of other changes are worth flagging for anyone coming to these contracts for the first time:

What does the stricter variations regime mean in practice?

In practical terms, it means a contractor can no longer afford to leave a grey area unaddressed. Anything capable of affecting price or time has to be raised as a specific variation order claim and raised without undue delay. At the same time, the threshold above which the employer can no longer instruct further variations has been raised compared with NS 8407, and the point at which the contractor stops being bound by the contract's original rates has also shifted.

The upside is greater predictability once the system is followed properly. The downside is that it demands much more disciplined notification and record-keeping – a contractor without solid procedures in this area will soon find claims falling away as the project progresses. For an overseas contractor unfamiliar with Norwegian contract practice, this is worth building into your project controls from the outset, not retrofitting once a dispute is already brewing.

This heightened focus on variations is no accident. In May 2025, in the widely discussed Nye Jordal Amfi case (HR-2025-977-A), the Norwegian Supreme Court clarified several central questions concerning an employer's power to instruct variations under NS 8407 clause 31.1 – including confirming that a contractor can't simply claim a “market rate” once the cap on instructed variations has been exceeded. The case is a useful illustration of how quickly unclear change management and poor documentation can become expensive on a large project, and it underlines exactly why the industry wanted a tighter, more traceable system.

Why does the ground conditions reference basis matter so much?

The answer lies in the consequences: Whoever carries the risk on ground conditions can end up facing a substantial bill if what lies beneath the surface turns out to be different from what was assumed. Ground conditions have long been one of the most contentious issues in Norwegian construction disputes, which is precisely why NS 8408 and NS 8418 introduce the reference basis – a concrete, agreed starting point against which the actual conditions are measured.

As a general rule, the employer picks up the bill if reality departs from the reference basis by more than could reasonably have been expected. The counterweight is that the contractor is under a clear duty to investigate the ground and attend a site inspection before submitting its tender and bears its own risk for whichever solutions and methods it chooses to adopt. The more thoroughly the reference basis is prepared at tender stage, the safer both parties stand once the project later runs into surprises below ground – something international bidders should factor into their due diligence before pricing a Norwegian project.

Summary

NS 8408 and NS 8418 give the industry a long-awaited tool for the very largest and most complex construction projects, built around a comprehensive variations regime, a new reference basis for ground conditions, and structured mechanisms for cooperation and dispute resolution. For projects that genuinely need this level of regulation, the standards can help reduce disputes and deliver a safer outcome. At the same time, they demand real investment in contract procedures, documentation and know-how from day one – an investment that matters even more for an international party navigating the Norwegian construction market for the first time.

Considering NS 8408 or NS 8418 for a project in Norway, or need help getting up to speed on the new contract provisions before your next tender? Get in touch with our team at Aider Legal – we advise both employers and contractors, including international parties new to the Norwegian market, on contract strategy, negotiations and dispute resolution in major construction projects.