Construction contracts under AB 04 and ABT 06: cost and likely outcome hinge on documentation created while the works were running, not on contract value. A party that logged variation orders, delay notices and defect remarks in the required form typically recovers most of its claim; one relying on informal correspondence usually settles for less.
Who this concerns
This situation arises for main contractors, subcontractors and developers operating under AB 04 (for contracts where the client carries design responsibility) or ABT 06 (for turnkey contracts where the contractor also designs). It surfaces whenever a project runs into a variation, a delay, or a defect that the parties did not anticipate at signing, and one side starts calculating what the dispute is likely to cost against what it might recover.
It also concerns anyone reviewing an existing Swedish construction contract before a claim is raised: a project manager assessing whether a change order was properly documented, a finance director estimating exposure on a delayed handover, or in-house counsel preparing a response to a claim for additional payment, the kind of review our contracts and transactions practice carries out before a position is taken.
Where the contracting party sits outside Sweden, the position changes in three respects. First, the foreign principal rarely has direct visibility into the day-to-day site correspondence that decides these disputes, because that correspondence runs through a local project manager or site agent who may not flag issues in time. Second, service of notices and claims under AB 04 and ABT 06 assumes a Swedish-based recipient able to act within the contractual time limits; a foreign head office receiving forwarded correspondence with delay loses days that later matter. Third, enforcement of any resulting award or judgment against a Swedish counterparty, or by a Swedish counterparty against foreign assets, follows a separate track from the underlying contract dispute and should be assessed before, not after, a claim is filed.
What the law says
AB 04 and ABT 06 are standard-form contract terms drafted by industry bodies, not statutes. They apply only if the parties have expressly incorporated them into the underlying agreement; there is no default rule under Swedish law as it currently stands that reads them into a construction contract that is silent on the point. Where the parties have incorporated one of the forms, its wording takes precedence over general contract law on the matters it covers, on the basis that industry-drafted terms reflect an allocation of risk the parties are taken to have accepted.
The forms set out procedures for ordering variations, notifying delay, claiming additional payment and raising defects. Where a party fails to follow the notice procedure, the form itself decides the consequence, not general contract law: a claim raised outside the form's own channel is typically treated as not properly made, regardless of whether the underlying work or delay actually occurred. General contract law fills the gaps the forms leave open, principally on questions of interpretation where the wording is ambiguous, and on issues the forms do not address at all, such as pre-contractual misrepresentation.
Where the underlying agreement amends specific clauses of AB 04 or ABT 06, as commercial contracts frequently do, the amended clause governs and the unamended standard wording does not survive by implication. This is the point most disputes turn on: which version of the clause, standard or amended, applies to the fact pattern in front of the parties.
How it works in practice
Raising and disputing a variation (ÄTA)
A variation under AB 04 or ABT 06 is formally an ÄTA, short for ändring, tillägg, avgående arbete: a change, an addition, or work removed from scope. The forms require the contractor to notify the client before carrying out work outside the original scope and price it separately, rather than simply proceeding and invoicing afterwards. Disputes arise almost exclusively where this sequence was not followed: work was carried out on a verbal instruction, an email exchange that never resulted in a signed order, or a site meeting minute that one party treats as approval and the other does not.
Delay notices and liquidated damages
Both forms require the contractor to notify delay as it becomes foreseeable, not once completion has already slipped. A notice given late is frequently treated as no notice at all for the purposes of extending the completion date, which leaves the contractor exposed to liquidated damages calculated from the original date rather than a revised one. The client's own conduct matters here too: instructions that themselves caused delay, or a failure to give access to the site, can shift responsibility back, but only if that sequence of events was also documented at the time.
Defects, remedial work and the completion inspection
The completion inspection, slutbesiktning, is the point at which defects are formally recorded and the contractual clock on remedial obligations starts running. A defect not listed at that inspection is harder to claim later, because the record created at the inspection is what a court or arbitral tribunal will look at first. Contractors who address defects informally between inspection and handover without documenting the fix create the same problem in reverse: no record that the item was actually closed out.
Payment withholding and set-off
A client faced with a defect or delay claim will often withhold payment against the final account rather than pay and sue separately. Whether that withholding is contractually justified depends on whether the underlying claim was raised through the correct channel and within the time the form allows; an unjustified withholding exposes the client to interest and, in some cases, to the contractor treating it as a repudiatory breach.
Final account negotiations
Most disputes under AB 04 and ABT 06 are resolved at final account stage, before any tribunal becomes involved, because by that point both sides can see the full set of ÄTA orders, delay notices and defect records against each other and can price the dispute rather than argue about principle. A party that reaches this stage with an incomplete paper trail negotiates from a materially weaker position, independent of the merits of its underlying claim.
Escalation: arbitration or general court
Where the final account cannot be agreed, the dispute resolution clause in the underlying contract, not the standard form by default, decides whether the matter goes to arbitration or to the general courts. Commercial construction contracts frequently specify arbitration, which changes the cost profile of the dispute: arbitrator fees and institutional fees are paid up front by the parties, in contrast to the fee structure of general litigation.
Foreign principals and cross-border procurement
Where the client or the contractor is a foreign entity procuring or delivering works in Sweden through a local subsidiary or branch, three practical points change. The party actually signing site instructions and completion documents is often not the party who will bear the cost of a claim, which creates internal delay in escalating disputes upward before the contractual time limits close. The governing law and forum clause in the underlying contract may not match the assumption the foreign parent is working from, since AB 04 and ABT 06 are drafted against a Swedish legal background even when the wider commercial contract is negotiated abroad. Finally, any arbitral award or judgment obtained against a Swedish counterparty with limited local assets will need to be enforced wherever those assets actually sit, which is a separate exercise from proving the underlying claim.
What to check before calculating exposure
- Whether the underlying agreement expressly incorporates AB 04 or ABT 06, and which edition
- Whether any clauses of the standard form were amended, and the wording of the amendment
- Whether each disputed item was raised as an ÄTA order in the form the contract requires
- Whether delay notices were given before, not after, the completion date was affected
- Whether the completion inspection record lists the defect now being claimed
- Whether payment withheld against the final account was linked to a specific, raised claim
- Whether the dispute resolution clause specifies arbitration, and under which rules
- Whether time limits for notice or for bringing a claim have already started running
Frequently asked questions
Does AB 04 or ABT 06 apply automatically to a Swedish construction contract?
No. Both are standard-form terms that apply only where the underlying agreement expressly incorporates them. A contract silent on the point is governed by whatever the parties actually agreed and by general contract law, not by the default assumption that one of the forms applies because the works are a construction project.
What happens if a variation was carried out without a signed ÄTA order?
The contractor's claim for the additional cost becomes harder to prove, because the form's own procedure for pricing and approving variations was not followed. It is not automatically lost, but the contractor is left reconstructing what was agreed from correspondence, site minutes and conduct, rather than pointing to a document the form itself treats as decisive.
Can a foreign parent company be joined to a dispute under AB 04 or ABT 06?
That depends on who actually signed the underlying contract, not on who controls the signing entity. A foreign parent is not automatically a party to a dispute brought against its Swedish subsidiary; joining it requires a separate contractual or corporate basis, which should be assessed on the group structure rather than assumed either way.
The numbers
Neither AB 04 nor ABT 06 fixes a universal number of days for notice, a universal percentage for liquidated damages, or a universal retention amount: those figures live in the special conditions the parties negotiate on top of the standard form, and they vary by edition, by project type and by what the parties actually agreed to amend. Quoting a specific day count or percentage in the abstract would misstate a figure that is, in every case, a matter of the individual contract's special conditions rather than the standard form's default text.
What does scale predictably with cost is the number of disputed items carried into the final account and the length of the documented delay: each additional undocumented ÄTA order or each week of delay without a matching notice adds to the volume of correspondence a lawyer has to reconstruct into a coherent claim, and reconstruction work costs more, per item, than working from a contemporaneous record.
Where it usually goes wrong
The most common failure is treating a verbal instruction to proceed as equivalent to a signed ÄTA order. Site staff on both sides frequently agree changes informally to keep the programme moving, on the understanding that paperwork will follow; where it does not follow, one side is left arguing that a document exists in substance even though the form requires it in a specific format.
A second failure is assuming the standard form applies by default because the project is a construction project. Where the underlying agreement does not incorporate AB 04 or ABT 06, or incorporates an outdated edition without updating cross-references, the parties can end up litigating what they actually agreed rather than applying the form's built-in mechanism, which defeats the purpose of using a standard form in the first place.
A third failure, specific to groups with a foreign parent, is escalating a dispute internally only after the contractual notice period has closed. Because the standard forms measure time from when an event becomes known or foreseeable on site, not from when head office is informed, a delay in internal reporting can extinguish a claim that was factually sound but procedurally late.
Finally, where a project genuinely involves supervening events outside either party's control, rather than a straightforward disagreement about scope or delay, the analysis shifts away from the ÄTA and notice mechanics described here and toward the separate question of whether the event in fact excuses performance; that situation is addressed in our analysis of force majeure and changed circumstances, which covers cost and likely outcome on that different fact pattern.
What to do next
Working out where a specific dispute sits on the spectrum above, and what it is realistically worth once the paper trail is assembled, is not something that can be done from the standard form alone; it requires reading the actual site correspondence, ÄTA orders, notices and inspection records against the contract as amended. That review is the natural next step once the position above no longer matches what has actually happened on a live project.
Lodline's contracts and transactions practice assesses construction disputes on this basis: reading the record that exists, identifying what is missing, and giving a view on likely outcome and cost before a claim is formally raised or defended. Where the immediate question is whether to escalate a live dispute, book a case assessment rather than continuing to build a position without a documented view of what the record actually supports.