Subcontractor without the client's consent

What the law says about the execution of work by other persons

The default statutory rule gives the contractor relatively broad freedom. The contractor either performs the work personally or has it performed under their personal supervision; this does not apply if the performance of the work is tied to the contractor's personal qualities or if it is not necessary given the nature of the work (Section 2589 of the Civil Code under Czech legislation).

For a standard construction or manufacturing contract, this means that the use of subcontractors is a legally anticipated and permitted procedure, unless the contract specifies otherwise. Where the execution of the work does not depend on the contractor's personal qualities, the contractor does not even need to personally supervise the subcontractors' work. Where it does depend on them, typically when the client selected a specific contractor for their personal expertise or reputation, the contractor must perform the work themselves, or at least under their personal supervision. A restriction can thus arise from the nature of the work even without an express prohibition in the contract.

This rule is non-mandatory (dispositive), and the parties can contractually deviate from it: expressly prohibit the use of subcontractors, make it conditional on the client's prior consent, or, conversely, expressly permit it. Without such an agreement, the contractor can rely on the law permitting the use of subcontractors for standard works. However, they must assess themselves whether the nature of the work or public law expertise requirements demand personal performance. Similar non-mandatory rules from which parties can contractually deviate also apply to other issues in business relations, as shown in the article on commercial contracts versus purchase orders.

When the contract requires consent to a subcontractor

For standard works, the client's prior consent to a subcontractor is not a statutory rule; it arises primarily when the contract establishes it as a condition. The mere fact that it is a major contract does not establish consent. A typical formulation is a provision according to which the contractor may not entrust the execution of the work or a part thereof to a third party without the prior written consent of the client, possibly with the exception of subcontractors listed directly in an annex to the contract.

The second common option is the contractor's obligation to merely notify the subcontractor, not to request consent. The client thus learns about the involvement of the subcontractor but does not have the right to reject them. This milder option gives the client an overview of who is actually working on the contract without preventing the contractor from operationally resolving capacity shortfalls.

The third option, applicable where the client wants to maintain control without lengthy approval for each subcontractor, is a pre-approved list of vetted subcontractors. The contractor can draw from it without further consent and will only request consent for subcontractors not on the list.

The choice between these options should correspond to how sensitive the contract is and how often the contractor actually changes subcontractors. For a one-off contract with a clearly defined scope of work, consent for each subcontractor individually makes sense. For a long-term framework relationship with repeated partial orders, an approved list is more practical because it allows the contractor to respond to capacity shortfalls without delay.

The fourth, less common option is a combination based on the type of activity: full consent for key parts of the work where specific expertise matters, and only a notification obligation for supporting work. This combination requires a more precise definition in the contract, but better corresponds to the real risk structure of more complex projects, where not all parts of the work carry the same weight for the final result.

What happens if a contractor uses a subcontractor without consent

Using a subcontractor in violation of a contractual consent condition is a breach of contract, not a ground for the invalidity of the performed work. If a party breaches a contractual obligation, they shall compensate the resulting damage (Section 2913 of the Civil Code). However, compensation assumes that the client proves and quantifies the damage; the mere breach of the clause without damage does not establish a claim for compensation.

At the same time, damages are not the only remedy. The client may insist on proper performance of the contract, which includes demanding that the contractor withdraw the unapproved subcontractor from the project, if this follows from the content of the obligation. If the breach is material, the client may withdraw from the contract without undue delay even without a specific withdrawal clause (Section 2002 of the Civil Code). A breach is material if the breaching party knew or must have known at the time of concluding the contract that the other party would not have entered into the contract had they foreseen it. In other cases, it is presumed not to be material.

Without a contractual penalty, the breach is therefore more difficult to penalize, though not without risk. The client must resort to general remedies: proving the occurrence and amount of damage for damages, and the materiality of the breach for withdrawal. If the subcontractor performed the work without defects and without delay, there is often no damage and materiality is difficult to prove. Contracts that handle this situation well therefore link the breach of the consent obligation to a contractual penalty, which can be claimed regardless of whether damage occurred (Section 2048 of the Civil Code), and to an express right to demand the replacement of the subcontractor.

However, with a contractual penalty, it is necessary to consider its relationship to damages. If a contractual penalty is agreed upon, under Section 2050 of the Civil Code, the creditor does not have the right to damages arising from the breach of the obligation to which the penalty applies. If an unapproved subcontractor could cause damage exceeding the penalty, the contract should expressly state that the right to damages is preserved alongside the penalty.

Furthermore, a client who discovers the use of an unapproved subcontractor only during execution faces a practical dilemma. Insisting on immediate replacement may delay the project more than if the subcontractor finished the work. A well-structured contract therefore gives the client a choice in advance between immediate replacement and subsequent approval. It should expressly state whether subsequent consent preserves an already accrued claim for a contractual penalty. If the penalty arises at the moment of the breach, subsequent consent does not necessarily cancel it on its own.

Such flexibility is beneficial for both parties. The client retains leverage in the form of a sanction even if they subsequently approve the subcontractor, and the contractor avoids a situation where formal insistence on replacement would deprive them of a subcontractor they actually need to complete the contract on time.

Special regime for public contracts

For public works contracts and contracts for services provided at a facility under the direct supervision of the contracting authority, the selected contractor is obliged to submit to the contracting authority the identification details of the subcontractors of these works or services, if known to them, no later than ten working days from the delivery of the notification of the selection of the contractor, or from the conclusion of the contract (Section 105(3) of the Czech Public Procurement Act). Subcontractors involved later must be identified before commencing their performance.

In addition, the contracting authority may require in the tender documentation that the participant specify in the tender the parts of the contract to be performed through subcontractors, or submit a list of them. For contracts for services, works, and supplies involving installation or assembly, they may also stipulate that designated significant activities must be performed directly by the selected contractor (Section 105(1) and (2) of the same Act). This can completely rule out transferring a key part of the performance to subcontractors, whether the general contractor wishes to do so or not.

A contractor bidding for public contracts must therefore consider, even before submitting a bid, what proportion of the performance they can handle with their own capacity and where they will have to declare subcontractors already in the bid. A subsequent change of subcontractor may be limited by the tender conditions, qualification rules, especially if the contractor demonstrated qualification through the subcontractor, or the contract itself. However, the mere replacement of a standard subcontractor is not automatically a modification of the commitment. If it simultaneously affects the content of the contractual commitment, the rules for modifying commitments under Section 222 of the Czech Public Procurement Act must also be assessed.

The contracting authority may also establish an obligation to identify subcontractors for further levels of the supply chain, not just for the direct subcontractors of the selected contractor. The general contractor must then also have an overview of who their subcontractors hire. They must reflect this obligation in contracts with their subcontractors, otherwise they will not be able to fulfill it themselves.

The identification obligation is deemed fulfilled if the details are entered in the construction logbook pursuant to another legal regulation (Section 105(5)). A properly kept construction logbook can thus serve a dual purpose: as a technical record of the construction progress and as fulfillment of the obligation towards the contracting authority. Contractors who keep the logbook formally and incompletely may lose the opportunity to fulfill the obligation in this way and must fulfill it independently.

Contractor's liability for subcontractors even with consent

If a debtor performs through another person, they are liable as if they performed themselves (Section 1935 of the Civil Code). Granting consent to a subcontractor therefore does not relieve the contractor of liability for the outcome of the work. The client generally has contractual claims from defects against the contractor, not against the subcontractor, with whom they have no contractual relationship. An exception is the special regulation for buildings and potential non-contractual liability for damage, if its prerequisites are met.

For buildings, the law goes further: if performance was defective, the contractor's subcontractor is jointly and severally liable with the contractor with respect to what they supplied, unless they prove that the defect was caused solely by a decision of the contractor or the person supervising the construction (Section 2630(1)(a) of the Civil Code). In the case of a defectively constructed building, the client can thus assert a claim against both the contractor and the subcontractor, which gives them better enforceability where the contractor is financially weaker than the subcontractor who actually performed the work.

Joint liability is the reason why vetting a subcontractor before granting consent makes sense even where the contract does not expressly require it. A defective part from an unvetted subcontractor impacts not only the contractor's reputation with the client but also their direct financial exposure, similar to a defective part incorporated into one's own product, which is discussed in the article on claiming a discount due to a machine defect. [[DOPLNIT ODKAZ — Vadný díl od subdodavatele poškodil váš výrobek, co řeší quality agreement, téma 17 ze semaforu; prolinkovat oběma směry]]

The advantage for the client is mainly procedural, not that the subcontractor bears a larger share of the damage than the contractor. The client does not need to have a contractual relationship with the subcontractor. However, they must assert and prove that it is a defect relating to what the given subcontractor supplied; any defect in the building is not sufficient. Only then does the burden of proof lie on the subcontractor to show that the defect was caused solely by a decision of the contractor or the supervisor.

How to set up consent in the contract correctly

The first step is to decide whether the contract requires consent before each deployment of a subcontractor, or whether a notification obligation or a pre-approved list will suffice. The choice depends on how critical the identity of a specific subcontractor is to the quality or credibility of the entire project.

The second step is to link the breach of the consent obligation to a specific, enforceable sanction, not just a general reference to damages. A contractual penalty for deploying an unapproved subcontractor and the right to demand their replacement give the client a tool they can use immediately, without proving the amount of damage. At the same time, it is advisable to regulate the relationship of the penalty to damages and to state expressly when a breach is material, authorizing withdrawal.

The third step is to address the situation where the contractor loses a subcontractor during the project and needs to find a replacement quickly. A strict consent process with no exception for urgent situations can slow down the contractor precisely when they need to act quickly to avoid a delay similar to the one described in the text on suspension of work and postponement of the completion date. [[DOPLNIT ODKAZ — Subdodavatel vás zdržel a sankce jde na vás, téma 18 ze semaforu; prolinkovat oběma směry]]

The fourth step is to align the contractual terms of consent with the requirements of the tender documentation for public contracts, so that the two regulations do not conflict. A contract with a general contractor that is silent on obligations under the Public Procurement Act can lead to the contractor meeting the conditions vis-à-vis the client but breaching obligations vis-à-vis the contracting authority, or vice versa.

The fifth step, particularly important for multi-year contracts, is the regular updating of the approved list of subcontractors as the actual structure of the supply chain changes. A list approved at the beginning and never updated ceases to correspond to reality and loses its control function, without either party necessarily noticing.

How exactly to set the scope of consent and its sanction for a specific contract depends on how critical the subcontractor's identity is and what the nature of the contract is. Therefore, the Prague-based Czech legal team at ARROWS always assesses this based on the specific type of performance, not according to a universal template contract clause.

Risks of a subcontractor without the client's consent

Concluding Summary

The law allows the contractor to have the work performed by a subcontractor under their supervision, unless the contract provides otherwise and the nature of the work does not require personal performance. Therefore, for standard works, the client's prior consent stems from the contract, not from the law itself. The value of a consent clause stands and falls with whether it is linked to an enforceable sanction, and the contractor remains liable for the subcontractor even with the client's consent.

For both the general contractor and the client, this leads to a clear task: to decide how strict a consent regime the contract actually needs, and to link it to a specific sanction for breach. Without a sanction, the client remains reliant on general remedies, which are more difficult and slower to apply in practice.

The Prague-based Czech legal team at ARROWS sets contractual terms for the involvement of subcontractors according to the type of contract, aligns them with public procurement requirements, and assesses the contractor's liability for subcontractors even where they have been properly approved. Write to us at consultation@arws.cz or review our contracts and negotiation practice.