Construction contracts under AB 04 and ABT 06: what to do in the first ten days depends on which clause has been triggered, not on how serious the problem feels. The party that notifies first, in writing, on the correct basis, keeps its position open; the party that waits usually finds the clock has already run against it.
Who this concerns
This is a question for two groups sitting on either side of a Swedish construction contract. The first is the main contractor working under AB 04, the standard form used for execution contracts where the client has already produced the design. The second is the design-and-build contractor working under ABT 06, where design responsibility sits with the contractor and the notice mechanics bite harder because more of the risk has already been allocated away from the client. Developers, project owners and subcontractors feeding into either chain face the same ten-day pressure from the opposite side of the table.
The trigger is rarely the contract itself. It is an event during performance: a hindrance that stops work, an instruction that looks like a variation, a defect discovered at handover, a delay that has started to cascade through the programme, or a change in ground conditions that nobody priced for. The contract only becomes relevant once one of these events has happened, and from that point the standard forms expect action, not analysis.
Where the counterparty, the parent company, or the project's financing sits outside Sweden, the first ten days carry extra weight. Notices addressed to a foreign head office often arrive later than the contract assumes, and a governing law clause naming a jurisdiction other than Sweden can override the default assumption that AB 04 or ABT 06 will be read against Swedish contract law. Security instruments such as parent company guarantees or bank guarantees issued abroad also need checking early: a notice sent to the wrong entity, or in the wrong language, can be treated as no notice at all.
What the law says
AB 04 and ABT 06 are not statutes. They are standard-form contract terms produced by the Swedish construction industry and incorporated into a specific agreement by reference, which means the printed text only applies to the extent the parties have not amended it. Swedish contract law leaves this area mostly non-mandatory, so the actual obligations in front of a reader are whatever the signed contract, including its appendices and any special conditions, says they are, under Swedish law as it currently stands.
What both forms share is a recurring mechanic: a party that wants to preserve a claim, whether for extra time, extra cost, or a defect remedy, generally has to raise it without undue delay once it becomes aware of the relevant circumstances. The forms do not always fix this at a specific number of days; the standard is contextual, and a court or arbitral tribunal will look at what a reasonably attentive contractor in that position ought to have known and when. That contextual standard is precisely why treating the first ten days as a working discipline, rather than waiting for a fixed deadline to appear, protects a position that would otherwise depend on an argument about reasonableness after the fact.
How it works in practice
Day one: identify the trigger and the clause it falls under
The first task is not drafting a letter. It is working out which mechanism has actually been triggered: a hindrance notice, a variation order dispute, a claim for prolongation, or a defects notification. Each has a different addressee, a different form of words expected, and a different consequence for getting it wrong. Treating all of them as "a problem with the project" and writing one general email is the single most common way a position gets weaker in week one rather than stronger.
Day one to two: put the notice in writing
A phone call to a site manager is not a notice under either form. It may be useful evidence of awareness, but it does not discharge the obligation to notify. The written notice needs to go to the contractually specified recipient, by the contractually specified method, and it needs to say plainly what has happened and what clause is being invoked. Ambiguous language that hedges on whether this is "just for information" tends to be read against the party who sent it.
What the notice needs to contain
A usable notice states the event, the date it was discovered or occurred, the clause being relied on, and, where the form requires it, a preliminary indication of the consequence being claimed, such as an extension of time or additional cost. It does not need to quantify the final claim in the first ten days. It does need to avoid language that could later be read as a waiver, a concession on causation, or an acceptance that the issue is the notifying party's own risk.
Building the contemporaneous record
Photographs, site diary entries, minutes of site meetings, and internal emails written before the dispute crystallised carry far more weight than a narrative reconstructed months later. The habit of logging events on the day they happen, rather than reconstructing them for a claim, is the difference between a position built on evidence and one built on memory.
Checking what the parties actually signed
AB 04 and ABT 06 are printed forms, but almost every real contract carries a schedule of deviations, special conditions, or a project-specific appendix that changes notice periods, addressees, or the consequence of late notification. Reading the standard form without checking the deviations schedule is a common and avoidable error; the deviations schedule usually wins.
ÄTA-work, hindrance, and delay are not the same notice
Additional and altered work, obstacles outside a party's control, and delay to the completion date are treated as separate mechanisms with separate notice requirements, even though a single event on site can trigger more than one of them at once. Sending a single letter that blends all three into one narrative often means none of them is notified properly.
Who else needs to be told
A notice under the construction contract does not automatically satisfy notice obligations to a project insurer, a performance bond issuer, or a parent company guarantor. Each of those relationships usually has its own notice clause, on its own timetable, and missing one of them can undermine security that would otherwise have covered the loss.
What to check in the first ten days
- The exact clause the triggering event falls under, not the general category of "problem"
- The contractually named recipient and method of notice, as amended by any deviations schedule
- Whether the completion certificate has already been issued, since this changes which remedies remain open
- Whether insurance, bond, or guarantee notices run on a separate clock from the construction contract notice
- Whether any site instruction, minute, or email sent in the meantime could be read as a waiver
- Whether the counterparty, its guarantor, or its parent sits outside Sweden, and what that does to service and governing law
If the ten-day window has already been missed
What matters at that point is not the missed clock, but the consequence written into the specific clause. Some notice failures are treated as fatal to the claim; others shift the burden of proof or narrow the remedy without extinguishing it entirely. The answer depends on which clause was missed and what the contract, as actually amended, says about the consequence, not on a general assumption that a late notice means a lost claim.
What can a phone call to the site manager achieve on its own?
Very little in contractual terms. It can establish that the other side was made aware of the event, which may matter later if a dispute turns on good faith or waiver, but it does not satisfy a written notice requirement under either form. Treat a phone call as a supplement to the written notice, sent on the same day, not as a substitute for it.
Does the ten-day figure come from the contract itself?
No. Neither AB 04 nor ABT 06 fixes a universal ten-day period for every type of notice; the "without undue delay" standard is contextual and varies with the type of event. Ten days is used here as a practical working discipline for getting the notice, the record, and the internal escalation done before the contextual standard starts working against the notifying party.
What is the first sign that a claim has already been compromised?
The clearest early sign is correspondence, sent before anyone thought about the dispute, that concedes the cause of the delay, accepts a variation as being at the contractor's own risk, or uses language suggesting the issue is minor and will be absorbed without cost consequence. That correspondence is often written in week one, by someone on site who did not know a claim would later depend on it.
The numbers
Neither AB 04 nor ABT 06 sets one figure that applies to every notice in every project. The relevant period, whether it runs from discovery of a defect, from an instruction being issued, or from a hindrance first affecting the works, is set by the specific clause invoked and by whatever the parties' own deviations schedule has done to the printed form. Reading the number printed in the standard text without checking the project-specific amendments is one of the most frequent, and most avoidable, errors at this stage.
What can be said with more confidence is what drives the cost of getting this wrong. It increases with the number of subcontractors whose own notice obligations run in parallel and depend on the main notice being correct; with the length of time between the triggering event and the first written notice; and with the absence of a contemporaneous record that would otherwise let a later claim be quantified without dispute over the underlying facts. None of that is a fixed figure. It is a description of what makes the eventual claim, if there is one, harder or easier to prove.
Where it usually goes wrong
The ten-day discipline stops being useful once the actual contract has departed substantially from the printed AB 04 or ABT 06 text, because at that point the relevant deadline, addressee, and consequence are whatever the deviations schedule says, and generic guidance about the standard form no longer applies without checking it against the signed appendix.
It also breaks down in multi-tier subcontracting chains, where a notice sent correctly up one level can still fail because the party above it did not pass an equivalent notice further up the chain within its own deadline, leaving the ultimate claim exposed even though the first notice was handled properly.
Where a dispute has already moved to arbitration or litigation, the first-ten-days framework is no longer the relevant discipline; the question becomes one of evidence and procedure within that forum, not one of notice mechanics on site.
Finally, where the relevant notice period has genuinely already expired before the problem was identified, more urgency does not recover the position. At that point the analysis shifts to whether the consequence of the specific missed notice is fatal to the claim or merely narrows it, which depends on the clause, not on how quickly anyone now moves.
What to do next
The first ten days are about discipline, not strategy: identify the clause, write the notice, keep the record, and check the deviations schedule before assuming the printed form applies unchanged. That work can be done without outside help in most cases.
What cannot reliably be done without outside input is judging whether a notice already sent has weakened the position, or whether a missed deadline is fatal to a specific claim rather than merely inconvenient. That judgment depends on reading the actual contract, the actual correspondence, and the specific clause against each other, which is where a construction and transactions review is worth having before further correspondence goes out.
Where the underlying event looks more like a change in circumstances than a straightforward defect or delay, for example a supply disruption or a ground condition nobody could have priced for, the mechanics differ again; that situation is addressed separately in the material on force majeure and changed circumstances.
Where the notices have already gone out and the question is whether the position still holds, the next step is to arrange an assessment of the position before any further correspondence is sent.