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Errors in design documentation in Polish construction — who pays? Articles 471 and 651 of the Civil Code

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Most disputes over additional works and standstill on Polish construction sites begin with the same event: the design documentation supplied by the employer turns out to be incomplete, contradictory or simply wrong. Who pays for the consequences? We answer on three levels — where the contractor’s duty of review under Article 651 of the Polish Civil Code ends, who decides on changing the design during construction, and which legal bases give the contractor a realistic chance of recovering money, with Article 471 of the Civil Code at the forefront.

The design comes from the employer — and the employer answers for its quality

The starting point is the division of roles under Article 647 of the Polish Civil Code (consolidated text: Dz.U. of 2024, item 1061). The contractor undertakes to hand over a structure „performed in accordance with the design and with the principles of technical knowledge”, while the employer undertakes to perform the acts connected with the preparation of the works required by the applicable provisions — in particular to hand over the construction site and provide the design. The legislature thus assigned designing to the employer’s sphere. Two further provisions reinforce this. First, under Article 648 § 2 of the Civil Code the documentation required by the applicable provisions forms a component part of the contract — the design is not auxiliary material but the description of what the contractor is to build. Second, Article 649 of the Civil Code directs that, in case of doubt, the contractor is presumed to have undertaken all works covered by the design — so the scope of the performance is defined by the design, not by the general purpose of the investment. How these provisions operate when determining the scope of a lump sum is discussed in detail in the article on the scope of works covered by a lump sum.

From this division of roles follows a simple consequence of which Polish courts regularly remind employers: whoever kept the designing for itself answers for its result. The contractor is merely to execute someone else’s design correctly.

The limits of the contractor’s duty of review — Article 651 of the Civil Code

The employer’s standard riposte reads: „you are professionals, you should have detected the error”. Its statutory anchor is Article 651 of the Civil Code:

„If the documentation supplied by the employer, the construction site, machinery or equipment are not fit for the proper execution of the works, or if other circumstances arise which may prevent the proper execution of the works, the contractor should notify the employer thereof without delay.”

— Article 651 of the Polish Civil Code, translation by the author

The provision imposes a duty of notification — not a duty to verify the design. The case law of the Polish Supreme Court has drawn this boundary consistently since the judgment of 27 March 2000, III CKN 629/98 (OSNC 2000, No. 9, item 173): the contractor need not carry out its own detailed calculations or hunt for flaws in someone else’s work, especially where the design came from a specialist design office. Eight years later the Supreme Court put it in a single sentence:

„The contractor is not obliged to check the design supplied to it in detail in order to detect its defects, and the claimant discharged the duty arising from Article 651 of the Civil Code […]”

— judgment of the Supreme Court of 25 April 2008, II CSK 613/07 (full text in the SAOS database)

Notably, in that case it was the contractor who won — the dispute concerned precisely the deficiencies of the design documentation supplied by the employer, and the Supreme Court upheld the amounts awarded to the contractor for additional works. The authoritative interpretation of Article 651 is contained in the judgment of the Supreme Court of 26 June 2008, II CSK 101/08 (LEX No. 637702):

„[T]he contractor’s duty defined in Article 651 of the Civil Code is to be understood as meaning that the contractor must notify the employer without delay that the investment cannot be executed on the basis of the design received, or that executing the works in accordance with the supplied design will result in a defective structure. In the latter case, however, what is meant are situations in which identifying the deficiencies of the supplied documentation does not require specialist design knowledge […]”

— judgment of the Supreme Court of 26 June 2008, II CSK 101/08, LEX No. 637702

In that same case the Supreme Court set aside the judgment of the court of appeal precisely because it had defined the scope of the verification duty imposed on the contractor too broadly, and recalled that Article 651 does not require the contractor to check the documentation supplied by the employer in detail in every case in order to detect its possible defects, since the contractor need not possess specialist design knowledge. The line is continued by the Supreme Court judgments of 25 April 2014, II CSK 417/13 (LEX No. 1486970) and of 25 November 2016, V CSK 138/16 (LEX No. 2216196). The Court of Appeal in Szczecin put it concisely and practically:

„[T]he contractor is not obliged under Article 651 of the Civil Code to check the design in detail. Reproachable conduct – from the standpoint of that norm – can be attributed to the contractor only where, having the possibility of noticing the defectiveness of the design without resorting to the specialist knowledge held by the designer, it failed to inform the employer.”

— judgment of the Court of Appeal in Szczecin of 23 April 2013, I ACa 133/13 (full text in the SAOS database), translation by the author

What is meant, then, are errors that leap to the eye without design knowledge — not a systematic audit of someone else’s work. It is worth noting that in the Szczecin case the contract itself obliged the contractor to acquaint itself with the documentation and report errors noticed, but did not specify how deep the verification was to go — and for precisely that reason the court measured it by the statutory yardstick.

A bar too thin and a bar too thick — where the boundary runs

The difference is easiest to see on the example of reinforcement. If the design provides for wire two millimetres thick where a reinforcement bar should be, the error is obvious to any contractor — silence burdens the contractor itself. If, however, the design provides for a bar twenty millimetres thick where structural considerations required twenty-five, the contractor has no way of establishing this: it does not know the structural calculations and has no duty to reconstruct them. Whether a defect was recognisable without design knowledge is decided in litigation almost always on the basis of an expert opinion — which is why securing the state of the documentation as at the date of tendering matters so much.

The Supreme Court spoke emphatically about the boundary of competences in an installations case in which the water and central-heating designs had been prepared by different, uncoordinated designers (judgment of 9 October 2014, I CSK 568/13):

„The claimant does not hold design qualifications for the installations forming the subject matter of the contract. The contract obliged it to install the installations in accordance with the design […]”

— judgment of the Supreme Court of 9 October 2014, I CSK 568/13, from the findings adopted as the basis of the decision, translation by the author

Since the contractor could not lawfully have designed the installations itself, it cannot be required to verify the work of those who do hold design qualifications. The same case — 720 wall chases in 127 apartments and an award of PLN 2,725,620 — is discussed at greater length in the article on additional works under a lump-sum contract.

Case study: cracking walls and an error hidden in the floor-slab calculations

How these rules work in practice is shown by the case closed by the judgment of the Court of Appeal in Warsaw of 5 March 2015, VI ACa 738/14 (LEX No. 1663096). After completion, the partition walls of a building began to crack. The developer sued the contractor, and the regional court awarded damages, holding that the contractor should have detected the errors of the design documentation both at the stage of an „initial examination” and of an „ongoing examination” during the works. The Court of Appeal changed the judgment and dismissed both claims. It recalled the rule from III CKN 629/98:

„[A]s part of checking the correctness of the supplied design documentation the contractor is not obliged to carry out its own detailed calculations in order to detect a defect of the supplied design, particularly where it was prepared by a specialist design office.”

— judgment of the Court of Appeal in Warsaw of 5 March 2015, VI ACa 738/14, LEX No. 1663096, translation by the author

On the facts, detecting the design error required specialist calculations of floor-slab deflection, and the designer himself kept assuring the contractor that the adopted solution was correct. The court’s conclusion is a model for this entire category of disputes:

„Since the defendant erected the building in accordance with the contract and with the design documentation forming its integral part, and in the construction works contract the parties did not extend the contractor’s liability beyond the content of Article 651 of the Civil Code […]”

— judgment of the Court of Appeal in Warsaw of 5 March 2015, VI ACa 738/14, LEX No. 1663096, translation by the author

— no contractual liability under Article 471 of the Civil Code for defects flowing from someone else’s design could be attributed to the contractor. In passing, the court added a remark to which we will return: under Article 17 of the Polish Construction Law (consolidated text: Dz.U. of 2025, item 418) the contractor is not even a participant in the construction process — its liability is shaped by the Civil Code, not by public law.

Two things are worth remembering from this case. First, courts of first instance are still capable of requiring an „initial and ongoing examination” of the design from the contractor — and lose to the settled Supreme Court line only on appeal. Second, the court expressly reserved that the parties could have extended the contractor’s liability beyond Article 651 in the contract. Clauses shifting a full design-verification duty onto the contractor must therefore be caught at the contracting stage — their effectiveness is discussed below.

Article 651 of the Civil Code is not a self-standing basis of liability

Structurally, Article 651 creates a duty of notification but does not itself decide on liability in damages — its source remains the general rules, that is Article 471 of the Civil Code (so the Supreme Court judgment of 30 September 2009, V CSK 89/09, LEX No. 1402683). In practice this means two things. A contractor who notified a noticeable defect frees itself from the charge of co-responsibility for its consequences. A contractor who kept silent about a defect recognisable without design knowledge may answer for the employer’s damage — but always within the limits of what was actually recognisable. How to carry out and document the notification so that it survives litigation is described step by step in the article on the protocol of necessity and documenting works.

The other side of the boundary: signing the contract without reading the design

The protection of the III CKN 629/98 line has its reverse, however. In case II CSK 417/13 a contractor charged with contractual penalties argued that the employer was responsible for the documentation and that detecting gaps at the stage of inspecting the site was not among its tasks. The Supreme Court described the scope of the duties thus:

„The scope of the duties of a contractor of construction works is indeed defined by Article 651 of the Civil Code. It follows from that provision that the contractor’s duty is to notify the employer without delay of any established defectiveness of the documentation supplied by the employer, of its unsuitability for the proper performance of the contract and of other circumstances which may prevent the proper execution of the works.”

— judgment of the Supreme Court of 25 April 2014, II CSK 417/13, LEX No. 1486970, translation by the author

Except that in that case a professional contractor had entered into obligations without acquainting itself with the building permit and the approved design at all — and a professional can be expected, before signing the contract and committing to a deadline, to look at the documents of fundamental significance. The contractual penalties stood. The lesson: Article 651 protects the contractor against a duty of specialist verification of someone else’s design, but it does not protect against the consequences of contracting blind. The design must be read — the way a contractor reads it: for buildability, calculation and time.

The double-liability trap: build to a flawed design or depart from it?

When a design error comes to light during the works, the contractor faces a dilemma. The contractor answers for the result — the structure is to be functional. If it builds strictly to the flawed drawings, it will erect a structure with a defect within the meaning of the warranty provisions, because the structure will not achieve the agreed usability. If it departs from the design on its own authority, it breaches Article 647 of the Civil Code — the structure is to be performed „in accordance with the design” — and exposes itself to the charge of improper performance of the obligation (Article 471), and even to the employer’s rescission of the contract for executing the works in a manner contrary to the contract. Both routes lead to the contractor being liable for someone else’s error.

There is one way out of the trap: the contractor does not decide alone but brings about a decision of the employer. That is exactly what the notification under Article 651 serves — it shifts the burden of choice to where the responsibility for designing is located. After the notification the employer may order building to the original design (the contractor is then protected, and the valuation of Article 655 of the Civil Code gives it the right to remuneration even where a structure executed according to the employer’s instructions is destroyed) or change the design solution. And here the real dispute about money begins.

Changing the design is not free of charge — though employers claim otherwise

In practice, after the notification the employer most often corrects the documentation and demands that the works be executed according to the changed solution — „within the lump sum”. Yet works resulting from the repair of a design error were not covered by the original description of the performance, and the lump sum prices the scope described in the documentation, not the risk of its defectiveness. We exposed the paradox of this practice in the survey article: the case law on the one hand releases the contractor from any duty of meticulous examination of the design, and on the other — through the lump-sum mechanism — makes it pay for the shortcomings of that design regardless of whether it reported them. A contractor who detected the defect, reported it and executed the works according to the corrected design is sometimes treated more harshly by the courts than one who detected nothing. The correct order of reasoning must be the reverse: first the qualification of the works (do they fall within the described scope of the performance), only then the question of how to settle them — an annex, a protocol of necessity, and in their absence the claims discussed below.

The designer decides on his own error — competences under the Construction Law

At the interface of civil and public law the contractor’s position weakens further, because the fate of a reported defect is in fact decided by the author of the design. The Construction Law entrusts the designer with explaining doubts concerning the design and the solutions contained in it (Article 20(1)(3)). Author’s supervision — exercised at the employer’s demand — covers confirming the conformity of the execution with the design and agreeing on the possibility of introducing substitute solutions, the statute providing for those solutions to be put forward by the site manager or the construction supervision inspector (Article 20(1)(4)). Finally, the assessment whether an intended departure from the approved design is material — and on that depends the need to amend the building permit — belongs exclusively to the designer (Article 36a(1) and (6)). The scope and content of the construction design are, by the legislature’s choice, flexible — they are to be adapted to the specific nature and character of the structure and the complexity of the works (Article 34(2)), so the level of detail of the documentation is largely decided by the designer himself. The check of the design by a second designer provided for in Article 20(2) covers only conformity with the regulations — not completeness or fitness for execution.

The contractor has no voice in this arrangement. As the Court of Appeal in Warsaw recalled in VI ACa 738/14, the contractor is not a participant in the construction process (Article 17 of the Construction Law) — the participant is the site manager, who has a statutory duty to manage the construction in a manner consistent with the design or the building permit (Article 22(3)). Changed documentation binds him as a matter of public law. It is hard to imagine the site manager — who on site operates within the contractor’s structure — refusing to execute the works according to changed drawings. But the public-law compulsion to execute does not decide the civil-law settlement.

Instructions of the designer and the inspector do not change the contract

The Polish Civil Code knows no unilateral right of the employer to order variations (unlike § 650b of the German Civil Code or the FIDIC conditions). The designer’s determinations and the inspector’s instructions are acts of a public-law or technical order — they are not declarations of the employer’s will. The contract is changed only by the employer’s own conduct: an express annex or conduct by implication, for example handing the contractor changed documentation with the expectation that it be executed. The designer can effectively agree a change of scope only when acting with the employer’s authority — a power of attorney granted expressly or following from the fact that the employer tells the contractor to follow the designer’s instructions and tolerates his acting in the employer’s name.

For the settlement, however, something else is decisive. If the parties agreed on the changed scope of works and the dispute concerns only remuneration, one can reach for the rule of the second sentence of Article 628 § 1 of the Civil Code applied by analogy — remuneration corresponding to the justified outlay of work. Since the case law allows Article 632 § 2 of the Civil Code to be applied by analogy to construction works contracts (resolution of a panel of seven judges of the Supreme Court of 29 September 2009, III CZP 41/09, OSNC 2010, No. 3, item 33), consistency requires the analogy from Article 628 § 1 to be allowed as well. The practical obstacle is that the employer usually declares from the outset that it will not pay for the changed works — and with so open a dispute over payment it is difficult to speak of the agreement which triggers the interpretative rule. What remains then are the claims described below.

Is „providing the design” an obligation whose breach gives rise to damages?

The question sounds technical, yet it decides the fate of a claim under Article 471 of the Civil Code against the employer. Damages for improper performance of an obligation are due only where a duty of the debtor was breached. The dispute over how to classify the duty to provide the design has been running in the literature for years and has two camps.

Arguments for a duty of the debtor

This classification is supported by the wording of Article 647 of the Civil Code, which says expressly that the employer „undertakes” to perform the preparatory acts, including providing the design. A systemic argument is also invoked: the provisions on construction works contain no counterpart of Article 640 of the Civil Code, which for the contract for a specific work governs the consequences of the ordering party’s lack of cooperation — „If the cooperation of the ordering party is needed for the performance of the work and there is no such cooperation, the party accepting the order may set the ordering party an appropriate time limit with the warning that after its ineffective expiry it will be entitled to rescind the contract” (Article 640, translation by the author). Since the legislature described the employer’s preparatory acts separately and in the language of obligation, they are said to be something more than cooperation. Against this background the case law has allowed the contractor to rescind the contract on the terms of the debtor’s default where the employer failed to hand over the construction site.

Arguments for a duty of cooperation of the creditor

The prevailing part of the literature answers, however, that the employer provides the design above all in its own interest — without the design its investment will simply not come into being. The employer’s main performance is payment of the remuneration, and providing the design is a concretisation of the creditor’s duty to cooperate under Article 354 § 2 of the Civil Code. The consequences of a breach then lie not in Article 471 but in the provisions on the creditor’s default.

Our position and the practical conclusion

In our assessment the second view is closer to the structure of the Code. If the creditor’s preparatory acts formed part of the „obligation” to which the debtor’s default relates, Article 640 would be entirely redundant — the legislature created a separate rescission right for the contract for a specific work precisely because the ordering party’s lack of cooperation is not the debtor’s default. Nor does this classification leave the contractor unprotected: „In the event of the creditor’s default the debtor may demand compensation for the resulting damage” (Article 486 § 1 of the Civil Code, translation by the author), and the creditor is in default, among other cases, when it refuses to perform an act without which the performance cannot be rendered (Article 486 § 2) — which, where there is no workable documentation, describes the situation directly. One painful difference must be remembered: a creditor’s duty of cooperation cannot be enforced in court, nor can rescission under Article 491 § 1 be based on its breach. The case law moreover refuses to reach for Article 640 by analogy in construction cases (so the Court of Appeal in Poznań in the judgment of 10 July 2013, I ACa 472/13, LEX No. 1353800), so a contractor paralysed by the lack of documentation has no simple exit from the contract — all that can be considered is termination of a continuing obligation for important reasons applied accordingly (Article 365¹), which remains an open question.

Because the courts are not uniform in this classification, the statement of claim should be constructed in the alternative: Article 471 as the principal basis, Article 486 § 1 as the alternative one. That closes the opponent’s cheapest line of defence — the dispute over the label of the duty stops deciding the outcome.

Two caveats before you sue the employer under Article 471

Even on the most favourable classification, two weaknesses of the damages claim must be seen honestly. First, Article 647 cannot be read as a duty to provide a design that is complete from the outset and immune to any later changes. The requirements for the content of the design are formulated flexibly (Article 34(2) of the Construction Law), and the level of detail is a matter of the designer’s judgment — a certain margin of corrections is built into the construction process and does not of itself evidence improper performance of the duty. Second, causation tends to be a problem: the pecuniary loss does not arise from the mere handing over of flawed documentation, but only from the fact that the contractor — compelled by the situation — performed the remedial works at its own cost. The employer will therefore argue that the damage is the consequence of the contractor’s own decision. The answer to both objections is careful documentation of the course of events: the notification under Article 651, a demand for the employer’s decision, a written reservation of reimbursement before commencing the disputed works.

The map of the contractor’s claims for documentation errors

A blind alley: pre-contractual liability

One more construction looks tempting — since the awarding party prepared the investment badly before the contract was even concluded, it might be liable for fault in contracting (culpa in contrahendo). Polish law, however, knows only point-specific information duties. Article 72 § 2 of the Civil Code covers conducting negotiations in breach of good customs, and tort liability under Article 415 requires proof of fault and of unlawfulness understood more broadly than the mere careless preparation of documentation. On top of that comes an evidentiary barrier that is practically impassable: the contractor would have to show that, properly informed, the employer would have concluded the contract with it at a higher price — whereas an employer agreeing a lump sum assumes precisely that the price will not rise. Claims on this basis should not be made the foundation of a lawsuit in disputes over defective documentation.

Public procurement: ambiguities must be asked about

In a public tender, describing the subject matter of the contract unambiguously and exhaustively is the awarding entity’s duty (Article 99(1) of the Public Procurement Law). But a contractor who notices an ambiguity and stays silent is playing with fire. A manufacturer learnt this after building for a municipality a refuse-truck body that did not fit part of the refuse containers used in the municipality — without first asking what containers were in use. The Supreme Court dismissed its cassation appeal against the judgment upholding contractual penalties:

„[I]n the given circumstances of the public procurement order being placed and accepted, and of the doubts existing on the contractor’s side, Article 38 of the Public Procurement Law constitutes, in conjunction with Article 354 § 2 of the Civil Code, not only a right but also a duty of the contractor to apply to the awarding entity for an explanation of the content of the terms of reference […]”

— judgment of the Supreme Court of 5 June 2014, IV CSK 626/13, LEX No. 1491332, translation by the author

The judgment was given under Article 38 of the previous statute of 2004 — today its counterpart is Article 135 of the Public Procurement Law, under which the contractor may apply to the awarding entity for an explanation of the tender documents (SWZ) and the awarding entity is obliged to provide explanations. The practical rule is therefore: turn a doubt noticed before submitting the tender into a written question. Questions and answers become part of the procurement documents, bind the awarding entity and build the evidentiary record for a dispute — and a failure to ask about a noticeable ambiguity may be counted against the contractor as a lack of professional diligence (Article 355 § 2 of the Civil Code). Hidden design defects which cannot be noticed before tendering are of course outside this rule — there the protection of the III CKN 629/98 line remains.

Declarations on the completeness of the documentation — what they really mean

Contract templates are full of clauses along the lines of „the contractor has acquainted itself with the design documentation and considers it complete and sufficient for the performance of the subject matter of the contract”. Their effectiveness has limits. First, a template is interpreted against its author. The Supreme Court has settled that the in dubio contra proferentem rule operates in professional dealings as well:

„[I]nterpretative doubts which cannot be removed by means of the general directives of interpretation of declarations of will should be resolved to the detriment of the party which drafted the text giving rise to those doubts (in dubio contra proferentem) […]”

— judgment of the Supreme Court of 8 October 2004, V CK 670/03, OSNC 2005, No. 9, item 162, translation by the author

„[D]oubts are to be construed to the detriment of the party which drafted the contract. The risk of doubts arising from unclear contractual provisions which cannot be removed by way of interpretation should be borne by the party which drafted the contract.”

— judgment of the Supreme Court of 15 September 2005, II CK 69/05, LEX No. 311311, translation by the author

Second, a declaration of knowledge about someone else’s design does not create competences the contractor does not have — professional diligence under Article 355 § 2 of the Civil Code does not encompass design knowledge, so a general „I confirm completeness”, reasonably construed, reaches as far as defects are recognisable without that knowledge. Third, in public procurement a provision burdening the contractor with the consequences of defects in the awarding entity’s documentation collides directly with Article 433(3) of the Public Procurement Law. Quite different, however, are assurances about facts from the contractor’s own sphere — in case II CSK 101/08 it was the contractor’s own declaration that the quantities from the survey sufficed to perform the contract that genuinely sank its later claims, and in case IV CSK 460/07 (judgment of the Supreme Court of 14 March 2008, LEX No. 453070) the contractor’s own tender bill of quantities covering the disputed windows worked against it. The boundary is clear: the contractor does not answer for someone else’s design, but it does answer for its own assurances. More on the evidentiary force of one’s own documents in the article on documenting works.

Design defects are not a „change of circumstances” under Article 632 § 2

A frequent error of classification costs the parties years of litigation. The defectiveness of the documentation is inherent in the contract from the outset and originates from the sphere controlled by the employer — it is therefore not an extraordinary external event that would justify a judicial increase of the lump sum:

„[A] material change of circumstances within the meaning of Article 632 § 2 of the Civil Code concerns exclusively an external event, independent of the parties, which they were unable objectively to foresee at the date of concluding the contract. Excluded under this provision are circumstances dependent on the parties, as well as random events of an individual character threatening the contractor with a gross loss.”

— judgment of the Supreme Court of 21 February 2013, IV CSK 354/12, LEX No. 1311808

In that very case additional works worth PLN 400,337.73 resulted among other things from defects of the documentation, and the lower courts were reproached for confusing the regimes. Claims arising from design errors run through the settlement of the works and damages — not through the judicial increase of the lump sum under Article 632 § 2, which is reserved for external shocks such as a sudden surge in prices.

The lump sum is no shield against someone else’s errors

Finally, the argument that returns most often in employers’ pleadings: „we agreed a lump sum, so the contractor took over all the risks”. The lump sum fixes the price for the scope described in the documentation — it does not transfer to the contractor the risk that the documentation is bad. The opposite reading would mean liability without fault for someone else’s errors and would reward the employer who saved money on designing. We develop this argument in the survey article on additional works and in the analysis of the scope of the lump-sum remuneration.

The employer’s and awarding entity’s perspective

For employers and awarding entities the mirror lesson of this case law is this. The cheapest insurance is documentation quality commissioned before the tender — a dispute with the contractor over the consequences of errors almost always costs more than a diligent verification of the design. Notifications under Article 651 must be answered in writing and quickly: a contractor’s report passed over in silence will later appear in court as proof that the employer knew about the problem and nevertheless ordered the works continued according to the original drawings. Clauses shifting the entire documentation risk onto the contractor give an illusory sense of safety — in public procurement they collide with Article 433(3) of the Public Procurement Law, and in private dealings they lose against the contra proferentem interpretation. Finally, the designer’s liability towards the employer for a defective design runs in parallel, on the basis of the design contract — and it is more often from the designer, not the contractor, that compensation for the damage flowing from errors of the design should be sought.

Frequently asked questions

Do I have to check the design before submitting a tender?

It has to be read the way a contractor reads it — for buildability, calculation and time. There is no duty of design verification or of detecting defects requiring specialist knowledge (the line since III CKN 629/98). Noticeable discrepancies are, however, worth reporting already at the tender stage, and in a public tender — turning into a question about the tender documents (Article 135 of the Public Procurement Law). Article 651 will not save a contract signed without looking at the documentation at all (II CSK 417/13).

The employer says that by signing the contract I accepted the documentation together with its defects. Is that right?

Not as regards defects that could not be noticed without design knowledge. A declaration on the completeness of someone else’s design does not transfer the designer’s responsibility to the contractor, and doubts as to the meaning of the clause burden the party that drafted the template (V CK 670/03, II CK 69/05). Assurances about facts from the contractor’s own sphere — for example about the sufficiency of a survey or the content of its own bill of quantities — are a different matter.

Can I claim the costs of standstill, and not only payment for the works?

Yes, the route for that is damages. The settlement of the works themselves does not cover standstill, prolonged maintenance of site facilities or the costs of redesign — those losses are pursued under Article 471 of the Civil Code, and if providing the design is classified as a duty of cooperation, under Article 486 § 1. The claim is best built on both bases in the alternative.

Under author’s supervision the designer ordered the works to be executed differently. Does that change the contract?

The designer’s determination alone does not — it is not a declaration of the employer’s will. The contract changes through an annex or by implication, when the employer hands over the changed documentation for execution. After every intervention of the designer one should therefore apply to the employer in writing for confirmation of the change of scope and agreement on remuneration, and upon refusal — reserve the return of the value of the works before performing them.

I performed the works according to the corrected design without an annex. Will I get paid?

The route to payment runs through the qualification of the works: if they go beyond the scope described in the original documentation, settlement through unjust enrichment comes into play (Articles 405 and 410 of the Civil Code), and independently of it damages covering the further losses. Contemporaneous evidence is decisive: the notification, the correspondence, the reservation of reimbursement.

The regional court held that I should have detected the designer’s error. Is that the end?

Not necessarily. Case VI ACa 738/14 shows that requiring an „initial and ongoing examination” of the design from the contractor contradicts the settled Supreme Court line — the court of appeal dismissed the claims because detecting the defect required specialist calculations and the contract did not extend liability beyond Article 651. It is worth examining whether the error was objectively recognisable without design knowledge and what exactly the contract stipulates.

The contract imposes on me a duty of detailed verification of the documentation. Is such a provision effective?

The parties may contractually extend the contractor’s duties beyond Article 651 — the Court of Appeal in Warsaw pointed to this possibility in VI ACa 738/14. The limits are the precision of the provision (a general clause loses against the contra proferentem interpretation, and the court will measure it by the statutory yardstick, as in case I ACa 133/13), the realism of the duty imposed and — in public procurement — the prohibition of Article 433(3) of the Public Procurement Law. Such a clause must be caught before signing and the associated risk priced.

Quotations from Polish judgments and legislation have been translated by the author. All translations are unofficial. The Polish texts are authoritative.

State of the law: 17 August 2026.

Author: Artur Barczewski PhD — Polish attorney-at-law (radca prawny), conducts construction payment disputes for contractors and employers alike. About the author · Discuss your case →