Construction contracts under AB 04 and ABT 06: timeline and cost turn on which general conditions apply, not on a statutory calendar. AB 04 covers works contracts where the client controls the design; ABT 06 covers design-and-build contracts. Both set the framework for variations and the final account, and cost follows from whether notice deadlines were met.
Who this concerns
Anyone signing a Swedish construction contract as client, main contractor or subcontractor is choosing, usually without much discussion, which set of general conditions will govern the project once the drawings are finished and the first delay notice has to be written. The choice sits inside the contract documents themselves: a reference to AB 04 or ABT 06, sometimes supplemented by industry-specific conditions for a particular trade, turns a two-page order confirmation into a project governed by several hundred clauses on risk, time and money.
The question comes up in three recurring situations. A client negotiating a fixed-price building contract wants to know what happens if the site turns out to hide something the survey missed. A contractor bidding on a design-and-build project wants to know how much design risk sits with them once ABT 06 is incorporated. A foreign parent buying into a Swedish construction group during due diligence wants to know whether the group's standard contracts leave open-ended exposure on ongoing sites. All three end up asking the same underlying question: what is the actual sequence of steps, deadlines and paperwork between signature and final acceptance, and where does cost stop being predictable.
The same question also surfaces on smaller works. A tenant fitting out leased premises, a housing association procuring a roof replacement, or a manufacturer extending a production hall all sign short contracts that incorporate AB 04 or ABT 06 by a single reference clause, without necessarily reading what that clause pulls in.
What the law says
Sweden has no statute that regulates construction contracts as a category the way, for instance, consumer sales are regulated. AB 04 and ABT 06 are not legislation; they are standard-form general conditions drafted by an industry committee representing clients, contractors and consultants, and they apply only because the parties have written them into the contract. Freedom of contract governs: the parties can incorporate AB 04 or ABT 06 wholesale, amend individual clauses, or exclude the general conditions altogether and draft bespoke terms.
Where the contract is silent and no general conditions have been incorporated, background principles of Swedish contract law fill the gap, applied by analogy from doctrine and dispute practice developed for construction specifically rather than from a dedicated code. This is the practical reason experienced parties incorporate AB 04 or ABT 06 rather than relying on the background regime: the general conditions convert open legal questions about defects, delay and payment into a fixed sequence of notices and deadlines that both sides can plan around.
How it works in practice
Choosing between AB 04 and ABT 06
The dividing line is design responsibility. Under AB 04 the client procures the design, typically through its own architect and engineers, and hands the contractor a defined scope to build. Under ABT 06 the contractor takes on the design obligation as well as construction, which shifts a meaningful share of the risk for buildability and coordination onto the contractor and changes how disputes about defects are framed later.
What makes up the contract
The general conditions are only one document among several. A properly assembled contract package under either form typically comprises the agreement itself, the general conditions, any supplementary conditions for the specific trade, the tender documents and drawings, the schedule, and any minutes of pre-contract meetings the parties have agreed are binding. Where these documents conflict, the general conditions themselves set a hierarchy; getting that hierarchy wrong at drafting stage is one of the more expensive mistakes on a project, because it resurfaces exactly when a variation or a delay claim needs to be priced.
Programme and the completion date
The contract fixes a completion date and, on larger projects, interim milestones. The programme attached to the contract is not decorative: it is the reference point against which every later claim for extension of time is measured. A contractor seeking more time for a hindrance has to show how that specific hindrance moved specific activities on the critical path, not simply that the project overall is running late.
Variations and instructed changes
Both forms include a mechanism for the client to instruct changes to the works, commonly referred to in the industry by the Swedish shorthand ÄTA, covering additions, alterations and reductions to the contracted scope. The mechanism exists so that changes do not have to be renegotiated as new contracts each time; instead they are priced and time-adjusted under the existing agreement, provided the instruction is given and confirmed through the channel the contract specifies.
Extensions of time
A contractor facing a hindrance, whether caused by the client, by weather outside the assumed range, or by a third party, has a right to extend the completion date, but that right is conditional on giving notice within the contract's own window and following up with the substantiation the general conditions require. Missing that window leaves the underlying hindrance unresolved and forfeits the contractual mechanism that would otherwise have protected the completion date, leaving the contractor exposed to delay consequences for something it did not cause.
Delay and its cost consequence
Where completion slips without a valid extension, the general conditions attach a cost consequence, commonly liquidated damages calculated per period of delay up to a cap, alongside the client's separate right to claim losses the liquidated damages regime does not cover. The commercial exposure on a delayed project is rarely the headline damages figure alone; it is the combination of liquidated damages, extended site costs, and the loss of any bonus the schedule was pricing in.
Defects, inspection and the final account
Completion is marked by a formal inspection, and the result of that inspection, rather than the calendar date on the programme, starts several other clocks running: the warranty period, the retention release, and the deadline for the final account. Defects noted at inspection are handled differently from defects that surface afterward, and the paperwork trail from the inspection protocol is frequently the single most contested document in a later dispute.
The final account and payment
The final account reconciles everything agreed during the project, contract price, priced variations, and any liquidated damages or claims, into a single settled figure. Getting the final account signed without reservation closes off arguments either side might otherwise have wanted to raise later, which is why the deadline and the procedure for raising a reservation matter as much as the substance of the claim itself.
Where the client or contractor sits outside Sweden
A foreign main contractor, a foreign parent company behind a Swedish subsidiary, or a Swedish contractor working for a foreign client changes several practical points without changing which general conditions apply. Currency and payment mechanics need to be fixed expressly, because AB 04 and ABT 06 assume a domestic payment chain. Security instruments, parent company guarantees in particular, need to be reviewed against Swedish enforcement practice rather than assumed to work the way they would at home. Where a dispute clause defaults to arbitration, a foreign party should check the seat, the language of the proceedings and whether an award will need to be enforced abroad, since that changes both cost and leverage in a way the general conditions themselves are silent on.
What to check before signing or before a dispute starts
- Which edition and which supplementary conditions are actually incorporated by reference, not assumed by trade custom
- Whether the programme attached to the contract is detailed enough to support a later extension of time claim
- Which channel is specified for giving notice of a hindrance or instructing a variation, and whether it has been used consistently on the project so far
- Whether the liquidated damages clause has a cap, and what it covers beyond pure delay
- Whether the inspection protocol and any noted defects have been signed by both sides
- Whether the final account has been submitted and, if so, whether any reservation was raised before the deadline
- Whether security instruments, guarantees or retention arrangements match what the contract actually requires rather than what was customary on a previous project
Frequently asked questions
Can a foreign investor screen a Swedish construction target's contracts as part of closing due diligence?
Yes, and the exercise is close to a standard contract review rather than something specific to construction: open variations, unresolved final accounts and pending extension of time claims on live sites are exactly the items that surface financial exposure a buyer would otherwise inherit unknowingly. The review should map every live contract against its programme and its notice history before closing rather than after.
Does an employee's design work on a design-and-build project trigger separate compensation questions?
It can, where the design output is patentable and produced by an employee rather than an external consultant, because employee inventions raise a compensation question that sits alongside, not inside, the construction contract itself. The construction contract allocates design risk between client and contractor; it does not settle what the individual designer is owed for that output.
What happens if a Swedish contractor needs to enforce a construction debt against assets held abroad?
Enforcing a Swedish judgment or award against foreign assets is a separate procedure from the construction dispute itself, and it starts only once the underlying claim is final. The construction contract's dispute clause determines where and how the claim is decided; asset tracing and recovery in the other jurisdiction is a distinct step governed by that jurisdiction's own enforcement rules.
The numbers
AB 04 and ABT 06 tie almost every contractor right, extension of time, additional payment for a variation, recovery for a client-caused hindrance, to a notice given within a period the general conditions themselves fix. The exact length of that period, and whether it runs from the event or from when the party became aware of it, depends on which edition and which clause the parties actually incorporated, and should be read from the contract documents rather than assumed from general industry practice. The same is true of the liquidated damages rate and cap, the retention percentage, and the warranty period: these are fixed by the contract, not by a background statutory scale, and two projects using the same general conditions can carry materially different figures if the parties amended the standard clause.
What is constant is the structure rather than the figure: a notice window that, if missed, forfeits the underlying right regardless of how strong the substantive claim would otherwise have been. Treating the notice deadline as a formality rather than as the mechanism that decides whether a valid claim survives is a common way a strong technical position turns into a lost one, and it is worth checking against the actual contract text before assuming a figure quoted informally on site is the one that governs.
Where it usually goes wrong
The general conditions work well when both sides read the programme the same way and give notice through the channel the contract specifies. They stop working, in practice, in three recurring situations.
The first is where the parties have amended individual clauses without checking how the amendment interacts with the rest of the general conditions, producing a contract that reads as AB 04 or ABT 06 but behaves differently on the one clause that matters. The second is where a subcontract has not been aligned with the main contract, so that a notice period, a liquidated damages cap or a defects definition differs between the two layers, leaving the main contractor exposed on one side of a claim it cannot fully pass down or up. The third is where the parties treat the general conditions as covering a question they were never drafted to answer, most often the design responsibility split on a project that mixes elements of AB 04 and ABT 06 without the contract saying clearly which regime governs which part of the works.
Resolving any of these situations requires reading the actual contract documents together, in the order the hierarchy clause sets, against what actually happened on site.
What to do next
Reading AB 04 or ABT 06 answers what the mechanism is supposed to do. It does not tell you whether a specific notice was given in time, whether a specific variation was properly instructed, or what a specific final account dispute is actually worth once the liquidated damages cap and the extended site costs are netted against each other. That assessment requires the actual contract documents, the programme as it stood at the relevant date, and the notice correspondence, read together.
Lodline's contracts and transactions practice works through exactly that documentation set for clients on both sides of AB 04 and ABT 06 contracts. Where a construction dispute sits inside a post-acquisition earn-out mechanism rather than the construction contract alone, the mechanics are different again, and are covered separately in our analysis of earn-out disputes after closing. For a specific contract or a live dispute, get in touch for an assessment of where the exposure actually sits before the next deadline in the contract passes.