Construction contracts under AB 04 and ABT 06: step by step move through five stages: tender and formation, execution with instructed changes, taking-over inspection, the defects liability period, and final settlement. AB 04 governs works where the client retains the design; ABT 06 shifts design responsibility to the contractor. Missing a deadline at any stage usually closes off a remedy rather than merely delaying it.
Who this concerns
The distinction between AB 04 and ABT 06 matters to whoever signs, administers, or inherits a Swedish construction contract: developers commissioning a building, main contractors pricing and executing the works, subcontractors bound in by reference through the main contract, and foreign parent companies funding or guaranteeing a Swedish project without running it day to day. The material below sits within the broader contracts and transactions practice, which covers negotiated commercial agreements more generally.
Both AB 04 and ABT 06 are standard-form general conditions produced by the Swedish construction industry's joint committee. Neither is legislation. They apply because the contract says they apply, usually by a single line in the special conditions referring to "AB 04" or "ABT 06" together with a stated edition. Once incorporated, the standard form's own deadlines, notice requirements, and document hierarchy take over from whatever the parties might otherwise have assumed applied by default.
The practical question this material answers is not which form to choose in the abstract, but what happens, in order, once one of the two is running: what has to be done, by when, in what document, and what is lost if a step is skipped.
What the law says
AB 04 and ABT 06 sit alongside, not inside, Swedish statute. Where the contract and the standard form are silent, background contract law fills the gap, under Swedish law as it currently stands. The standard forms themselves are agreed conditions negotiated between bodies representing clients and contractors; they are contract terms, and their content is set by the edition the parties chose, not by a public register.
What matters in practice is the order in which contract documents rank against each other. Both forms set out a hierarchy: agreed special conditions before the standard form's general conditions, drawings and technical descriptions in a stated order, minutes of site meetings only where the contract says they carry weight. A contract that departs from AB 04 or ABT 06 without restating this hierarchy leaves the ranking to whatever the parties actually wrote, which is where a surprising number of later disputes start.
Design responsibility is the structural difference between the two forms. Under AB 04, the client instructs a designer, hands finished drawings to the contractor, and carries the risk that the design itself is workable. Under ABT 06, the contractor takes on design together with construction, and a defect traced to the design is treated the same way as a defect traced to workmanship. Choosing the wrong form for the actual allocation of design work does not get corrected later by interpretation; it has to be corrected in the contract.
How it works in practice
Step 1: Tender and contract formation
The client issues tender documents describing the scope, the technical requirements, and which standard form and edition will apply. A contractor's tender is binding once accepted; qualifications entered against the tender that are not carried into the signed contract typically fall away. The signed contract, the accepted tender, and any minutes of pre-contract clarification meetings together form the document set that later governs interpretation, in the order the contract itself states.
Step 2: Choosing between AB 04 and ABT 06 for the actual scope
This step is frequently treated as settled once the tender is out, and frequently is not. Where the contractor is asked to develop or complete part of the design, even a limited part, ABT 06's allocation of design risk needs to sit alongside AB 04's allocation for the rest of the works, or the contract needs to say clearly which form governs which part. A hybrid scope without a stated hybrid allocation is a recurring source of later argument over who owned a defect.
Step 3: Instructions and additional or altered work
Work that goes beyond the original scope, referred to under both forms as ÄTA work, additions, alterations, and deviations, requires a written instruction before it is priced, and pricing before it is executed wherever that is practically possible. Verbal site instructions confirmed only after the fact routinely produce disputes over whether the work was in scope at all, and over what it should have cost.
Step 4: Progress, site meetings, and the running record
Both forms assume a running written record: site meeting minutes, instructions, and correspondence on programme and cost. This record is what later evidence disputes are decided from. A contractor that has not kept its own parallel record, rather than relying on the client's minutes, starts any later dispute a step behind.
Step 5: Taking-over inspection
Completion is marked by a formal taking-over inspection, slutbesiktning, at which an inspector, agreed or appointed under the contract, examines the works against the contract documents and records defects found on the day. The date recorded at this inspection starts the defects liability period and several other contractual clocks running. A party that does not attend, or attends but fails to enter a reservation on a point it disputes, generally loses the ability to raise that point later on the strength of the inspection record alone.
Step 6: The defects liability period
During the period following taking-over, the contractor remains responsible for putting right defects that appear, subject to the contract's own rules on what counts as a defect and how it must be notified. Defects noticed but not formally reported within the contract's own notice requirement are the single most common way a valid claim is lost, not because the defect was not real, but because the notice was late or informal.
Step 7: Final account and settlement
The contract closes with a final account reconciling the tendered price against instructed changes, adjustments, and any retained amounts. Both forms set a structure for how this account is to be presented and challenged; a party that lets the account stand unchallenged past the contractual window generally cannot reopen it later.
Documents the process generates
The paper trail that matters at each stage is specific, not general: the tender and its acceptance, the signed contract with its special conditions, written instructions for any ÄTA work with agreed pricing where reached, site meeting minutes, the taking-over inspection protocol with any reservations recorded on it, defect notices sent within the contract's own time limit, and the final account with supporting adjustment calculations. A dispute is, in practice, a dispute over which of these documents exists and what it says, more often than a dispute over the underlying facts.
Where the counterparty, guarantor, or financing sits outside Sweden
A construction contract that looks purely domestic on its face changes shape once a party outside Sweden is involved in funding, guaranteeing, or owning either side. A parent company guarantee given by a foreign holding entity needs to track the same currency, the same trigger events, and the same notice addresses as the underlying contract, or the guarantee and the contract can fall out of step at the point they are most needed together. Where a contractor's ownership changes during the project, including through a transaction that itself falls under merger control alongside investment screening, the client's practical concern is whether the entity performing the contract on the day of taking-over is still the entity that priced and signed it. Where a claim ultimately needs to be enforced against assets held outside Sweden, the mechanics look closer to cross-border asset tracing and recovery than to anything AB 04 or ABT 06 itself provides for, since neither form has enforcement machinery of its own.
What to check before treating either form as settled
- Which edition of AB 04 or ABT 06 the contract actually names, and whether any clause departs from that edition's default text
- Whether the scope includes any design element that sits uneasily with the form chosen
- Whether the document hierarchy is restated in the special conditions or left to the standard form's default order
- Whether ÄTA work instructions are being issued and priced in writing before execution, not confirmed afterwards
- Who is named to attend the taking-over inspection, and whether that person has authority to enter reservations
- What the contract's own notice period for defects actually is, and where that period is calculated from
- Whether any parent company guarantee or bond tracks the same currency, triggers, and notice address as the underlying contract
- Whether confidentiality around design documents survives a subcontractor's staff moving to a competitor, a question closer to trade secret protection for employee mobility than to the construction contract itself
Common questions
#### What happens if a defect is discovered after the defects liability period ends?
A defect notified after the contract's own liability period has closed is not automatically lost, but the contractor's responsibility under AB 04 or ABT 06 for that specific defect generally is. Whether any residual claim survives depends on whether the defect falls within a longer liability period the contract itself sets for certain categories of defect, and on general contract law principles that apply independently of the standard form.
#### Does a warranty given in the sale of a construction company cover defects arising later under AB 04 or ABT 06?
Not automatically. A warranty given on the sale of shares in a contracting company and a defects liability running under AB 04 or ABT 06 are separate regimes that can overlap on the same underlying fact pattern without one replacing the other; which one a claim should be brought under is worked through in warranty and indemnity claims regime.
#### Can the parties simply agree to skip the taking-over inspection to save time?
They can agree to a different procedure, but skipping the inspection without replacing it with something equivalent removes the fixed point from which the defects liability period, retention release, and several notice periods are otherwise calculated. What is saved in time at completion is typically spent later arguing about when those periods should be treated as having started.
The numbers
Neither AB 04 nor ABT 06 fixes a single universal deadline that applies regardless of what the parties wrote. Notice periods for defects, the length of the defects liability period, and the time allowed to challenge a final account are all set out in the contract documents themselves, and can differ between the standard edition's default text and whatever the special conditions substitute for it. Treating a deadline as known before checking the actual signed contract is one of the more common ways a genuinely fixed deadline gets missed.
What is consistent across both forms is the structure rather than the length: each deadline runs from an event recorded in writing, usually the taking-over inspection date or the date a notice was actually received, not from when a defect was first noticed informally or discussed on site. Establishing that trigger date correctly is usually more consequential than the length of the period that follows it.
Where it usually goes wrong
The recurring failure is not a misunderstanding of AB 04 or ABT 06 as such; it is a gap between what the contract requires in writing and what the parties actually did on site. Verbal instructions for additional work, executed and priced only after completion, routinely produce disputes over scope that a written instruction would have avoided entirely. A taking-over inspection attended without entering a reservation on a known issue closes off a point that could otherwise have been preserved at negligible cost.
The second recurring failure is choosing a form that does not match the actual allocation of design work, then trying to fix the mismatch by argument once a defect appears rather than by contract amendment beforehand. Once the works are under way, the form governing them is fixed by what was signed, not by what would have suited the actual scope better.
The third is treating a parent company guarantee as background comfort rather than as a document that itself needs to be checked against the underlying contract's triggers, currency, and notice provisions. A guarantee that does not track the contract it supports is frequently discovered to be misaligned only at the point it is called on, which is the point at which realignment is no longer possible.
None of these failures require a defect in the underlying works. They are failures of process around a contract that otherwise performs exactly as AB 04 or ABT 06 intends.
What to do next
Reading AB 04 or ABT 06 in full answers what each step requires. It does not tell you which document in your own contract set actually controls a given point, whether your special conditions have quietly displaced the standard form's default hierarchy, or whether a guarantee sitting behind the contract still tracks it. That review starts with the specific documents: the signed contract, the special conditions, and whatever instructions, minutes, and notices have accumulated since.
Where those findings change the price or the cost of a transaction involving the contracting entity itself, rather than a single dispute under the contract, the relevant next step is a structured review of due diligence findings and cost. Where the question is narrower, whether a specific notice, instruction, or inspection record actually preserves the position it was meant to preserve, that assessment is where self-directed reading stops and document-level review begins.