Cracks Beneath the Surface: Hidden Defects and Contractor Liability Under Turkish Construction Law

Construction defects do not always appear when a project is handed over.

A newly completed apartment may look perfect during inspection. Months later, water may begin penetrating through the roof. Structural cracks may emerge after seasonal movement. Waterproofing defects may appear only after heavy rainfall. Underground drainage may fail after prolonged use. Insulation problems, defective mechanical installations, inadequate concrete works or improperly constructed foundations may remain invisible for years.

This creates one of the most important questions in Turkish construction law:

What happens when a defect is discovered only after the construction has been completed and accepted?

Under Turkish law, contractors may remain liable for defective construction even after delivery. However, the owner’s rights depend on several interconnected issues:

• whether the defect existed in the completed work,
• whether it was apparent or hidden,
• whether the owner properly inspected the work,
• when the defect became discoverable,
• whether the contractor was notified in time,
• whether the work was accepted,
• whether the defect was deliberately concealed,
• which remedy the owner chooses,
• and whether the applicable limitation period has expired.

The core rules are contained in Articles 470–478 of the Turkish Code of Obligations No. 6098 (“TCO”), which regulate contracts for work and contractor liability for defects.

Understanding these rules is essential because a long statutory limitation period does not necessarily save a claim if the owner fails to notify the contractor properly after discovering the defect.

What Is a Construction Contract Under Turkish Law?

Article 470 TCO defines a contract for work (“eser sözleşmesi”) as an agreement under which the contractor undertakes to produce a work and the employer or owner undertakes to pay the agreed consideration.

Construction agreements are among the most important examples of this contractual structure.

The concept may cover works such as:

• construction of a residential building,
• construction of a villa,
• renovation of commercial premises,
• roof replacement,
• waterproofing,
• structural reinforcement,
• façade construction,
• mechanical and electrical installations,
• swimming pools,
• landscaping structures,
• and substantial refurbishment projects.

The contractor is not merely required to perform labour.

Article 471 requires the contractor to perform the work with loyalty and care, taking account of the employer’s legitimate interests. The standard of care is evaluated according to the professional and technical conduct expected from a prudent contractor operating in the same field.

This professional standard is particularly important in defect disputes.

A contractor cannot ordinarily defend defective workmanship simply by arguing:

“We always build this way.”

The relevant question is whether the completed work complies with the contractual requirements and the professional and technical standards expected from a competent contractor.

What Is a Defect in Construction?

A construction defect generally exists where the completed work does not possess the characteristics contractually promised or objectively required for its intended use.

A defect may arise from:

• defective workmanship,
• unsuitable materials,
• incorrect installation,
• defective waterproofing,
• structural deficiencies,
• deviations from technical specifications,
• failure to comply with approved drawings,
• inadequate insulation,
• incomplete works,
• improper drainage,
• mechanical or electrical deficiencies,
• or other failures affecting the value or usability of the construction.

Article 472 TCO also establishes an important rule regarding construction materials.

Where the contractor supplies the material, the contractor is responsible for defects in that material in a manner comparable to a seller. If the employer supplies the materials, the contractor must use them with appropriate care and must immediately warn the employer if the materials, the construction site or another circumstance endangers proper or timely completion. Failure to give the required warning can create liability for the resulting consequences.

Defect liability therefore extends beyond visibly poor workmanship.

A contractor may also be responsible where technically unsuitable materials were selected or where professional warning obligations were ignored.

Apparent Defects and Hidden Defects Are Legally Different

One of the most important distinctions in Turkish construction litigation is between apparent defects (“açık ayıp”) and hidden defects (“gizli ayıp”).

An apparent defect is generally one that can reasonably be identified when the completed work is properly inspected after delivery.

Examples may include:

• visibly broken tiles,
• unfinished painting,
• incorrectly installed doors,
• obvious cracks,
• missing fixtures,
• visibly defective flooring,
• or construction dimensions clearly inconsistent with the agreement.

A hidden defect is different.

It is a defect that cannot reasonably be detected during an ordinary and proper inspection at delivery and becomes identifiable only later.

Typical examples may include:

• waterproofing defects appearing after rainfall,
• concealed pipe leakage,
• deficiencies inside structural elements,
• hidden corrosion,
• defective insulation discovered during seasonal weather,
• foundation problems emerging after settlement,
• improperly designed drainage systems,
• or defects concealed behind walls, ceilings or façades.

The Turkish Code of Obligations does not simply treat these situations alike. Articles 474 and 477 establish different consequences depending upon when and how the defect can reasonably be discovered.

The Owner Has a Duty to Inspect the Construction

After delivery, the employer cannot simply ignore the work indefinitely.

Article 474 TCO requires the employer, after delivery, to inspect the completed work as soon as reasonably possible according to the ordinary course of events and to notify the contractor of defects within an appropriate period.

This duty is extremely important.

Imagine that a building is delivered with obvious water stains on the ceiling and substantial visible cracks.

The owner notices them but signs an unconditional acceptance document, continues using the property and says nothing to the contractor for a prolonged period.

The contractor may later argue that the defects were apparent, the owner failed to make the required inspection or notification and the work was therefore accepted.

A defect claim should therefore not begin years later with the question:

“Is the limitation period still running?”

The first question is often:

“Was the defect notified correctly and on time?”

The Owner Can Request an Expert Examination

Construction defects frequently require technical knowledge that an ordinary owner does not possess.

Article 474 expressly provides that either party may, at its own cost, request examination of the work by an expert and determination of the result in a report.

This mechanism is particularly valuable in disputes involving:

• structural defects,
• water ingress,
• concrete deficiencies,
• roof systems,
• mechanical installations,
• insulation,
• façade works,
• or disagreements concerning whether construction complies with the technical specification.

The Turkish Code of Civil Procedure also permits evidence determination (“delil tespiti”) where evidence may disappear or later become substantially more difficult to establish. A court may order inspection, expert examination or other evidentiary measures before the main proceedings under Articles 400–405 of the Code of Civil Procedure.

This can be strategically important where urgent repairs are necessary.

For example, if serious water penetration must be repaired immediately, the owner should consider documenting the defect technically before destroying the evidence through repair works.

What Happens If the Defect Appears Only Later?

This is the central rule for hidden defects.

Article 477 TCO provides that where a defect becomes apparent only later, the employer must notify the contractor without delay (“gecikmeksizin”) after the defect appears.

If the employer fails to do so, the work may be deemed accepted.

This produces a crucial practical rule:

The five-year limitation period applicable to buildings does not mean that an owner who discovers a defect today can safely wait several years before notifying the contractor.

The limitation period and the defect-notification requirement are different legal concepts.

Suppose:

A villa is delivered in January 2024.

A hidden waterproofing defect becomes apparent in November 2026.

The general five-year limitation period may still be running.

But the owner should nevertheless notify the contractor promptly after discovering the problem.

Waiting until 2028 merely because the five-year period has not yet expired can create a serious argument that the work was accepted under Article 477.

What Does “Without Delay” Mean?

Turkish law does not establish a universal numerical period such as seven days or thirty days for every hidden construction defect under Article 477.

The rule requires notification without delay after discovery.

Whether notification was timely therefore depends on the circumstances.

Relevant considerations may include:

• complexity of the defect,
• whether technical investigation was required,
• when the owner actually became aware that the problem constituted a defect,
• seriousness of the defect,
• whether expert inspection was necessary,
• and how quickly the owner communicated with the contractor.

From a risk-management perspective, however, the safest approach is straightforward:

Once a potentially significant hidden defect is discovered, it should be documented and notified to the contractor as quickly as reasonably possible.

Owners should not wait for the limitation period to approach.

Written Notice Is Strongly Recommended

A construction owner should be able to prove:

1. what defect was notified,
2. when it was notified,
3. to whom it was notified,
4. and what remedy was requested.

For this reason, significant defect notices should ideally be documented through reliable written evidence.

Depending on the circumstances, this may include:

• notarial notice,
• registered communication,
• contractual notice mechanisms,
• e-mail,
• documented electronic correspondence,
• site minutes signed by the parties,
• or other provable communications.

WhatsApp conversations may also become evidentially relevant, but for major construction disputes a properly structured formal notice is generally much safer.

The notice should identify the defect with reasonable specificity rather than simply stating:

“There are problems with the building.”

Where possible, photographs, technical findings and expert observations should be preserved.

What Happens After the Work Has Been Accepted?

Acceptance has serious consequences.

Article 477 provides that following express or implied acceptance, the contractor is generally released from liability for defects that should have been identified through the proper inspection process.

However, liability continues for defects deliberately concealed by the contractor and for defects that could not have been discovered through the required inspection.

The law also provides that if the employer neglects the required inspection and notification, the work is deemed accepted.

Accordingly, acceptance is not an absolute shield for the contractor.

A handover document does not necessarily eliminate liability for a genuinely hidden defect that could not reasonably have been identified at delivery.

This distinction becomes particularly important in contracts containing wording such as:

“The employer has inspected the works and accepts them completely and without reservation.”

Such language may be highly relevant to obvious defects.

It does not automatically transform a concealed structural problem into an accepted defect.

Deliberately Concealed Defects Are Treated More Seriously

Turkish law provides stronger protection where a contractor deliberately conceals a defect.

Article 477 expressly preserves contractor liability for deliberately concealed defects notwithstanding acceptance.

Examples could potentially include situations where a contractor:

• covers a known structural crack immediately before delivery,
• paints over serious water damage without correcting its cause,
• deliberately hides defective materials,
• knowingly encloses defective workmanship behind finishes,
• or provides misleading information designed to prevent discovery of a serious defect.

The legal consequences become even more significant in relation to limitation periods where the contractor’s conduct amounts to gross fault.

What Remedies Does the Owner Have?

Article 475 TCO gives the employer several alternative remedies where the contractor is responsible for defective work.

The appropriate remedy depends particularly on the seriousness and reparability of the defect.

1. Termination of the Contract

The employer may withdraw from the contract where the work is so defective or so seriously contrary to the agreement that it cannot reasonably be used or the employer cannot fairly be expected to accept it.

This remedy is primarily intended for serious defects.

Not every cracked tile or minor finishing problem allows the entire construction contract to be unwound.

There is also an important restriction concerning buildings constructed on the employer’s land.

Article 475 provides that where the work has been constructed on the employer’s immovable property and removing it would cause excessive damage, termination cannot be exercised in this manner.

This rule is highly relevant in construction litigation because demolishing an entire building to reverse the transaction may be economically and physically disproportionate.

2. Reduction of the Contract Price

The employer may keep the defective work and demand a reduction in the contract price proportionate to the defect.

This remedy may be appropriate where the building remains usable but:

• its value is reduced,
• an architectural deficiency cannot reasonably be corrected,
• the completed work is inferior to the agreed standard,
• or the owner chooses to retain the work despite the defect.

Technical and valuation evidence may be necessary to calculate the proper reduction.

3. Free Repair

The employer may demand that the contractor repair the defect at the contractor’s expense, provided that repair would not involve excessive cost.

In construction disputes, this is often the most commercially practical remedy.

Examples include:

• replacing defective waterproofing,
• repairing roof systems,
• correcting defective installations,
• replacing non-conforming materials,
• completing insulation,
• repairing façade defects,
• or correcting defective workmanship.

However, the requirement that repair not involve disproportionate expenditure means the economic relationship between the defect and the cost of correction may become important.

4. Damages

Article 475 expressly preserves the employer’s right to claim damages under the general provisions of the Turkish Code of Obligations.

Article 112 further provides that where an obligation is not performed or is improperly performed, the debtor must compensate the resulting damage unless the debtor proves that no fault can be attributed to it.

Depending on the circumstances, construction defect damages may potentially include:

• repair costs,
• damage to furniture or equipment,
• damage to other parts of the building,
• temporary accommodation costs,
• business interruption losses,
• loss of use,
• expert and technical expenses,
• and other causally connected losses.

The existence and amount of each loss must be proven.

Can the Owner Repair the Defect Through Another Contractor?

This question frequently arises where the original contractor refuses to return to the site.

The safest approach depends on the circumstances and contractual framework.

Where possible, the original contractor should generally first be formally notified of the defect and given an appropriate opportunity to remedy it, particularly where free repair is being requested.

If urgent measures are required to prevent further damage, however, waiting may itself increase the loss.

Article 473 also recognizes, during performance, circumstances in which the employer may warn the contractor to remedy defective or non-conforming work within an appropriate period and indicate that otherwise the work will be continued or repaired by a third person at the contractor’s risk and expense.

In practice, before appointing a replacement contractor in a substantial defect dispute, the owner should preserve evidence of the original condition, document the urgency and provide an appropriate notice whenever circumstances permit.

When Is the Contractor Not Responsible?

Not every defect is legally attributable to the contractor.

Article 476 provides that the employer cannot exercise defect rights where the defect resulted from instructions given by the employer despite an express warning by the contractor, or where the defect is otherwise attributable to the employer.

For example:

The owner insists on using an unsuitable waterproofing product.

The contractor clearly warns in writing that the product is technically inadequate.

The owner nevertheless orders the contractor to use it.

If leakage later results specifically from that decision, the contractor may rely on Article 476.

The quality of the contractor’s warning will often be critical.

A vague statement such as “this might not be ideal” may not carry the same evidential weight as a clear technical warning describing the foreseeable consequences.

The Contractor Also Has a Duty to Warn About Problems Provided by the Owner

Article 472 creates another important professional obligation.

If materials supplied by the employer or the construction site itself are defective, or another circumstance threatens proper or timely completion, the contractor must immediately notify the employer. Failure to do so makes the contractor responsible for the consequences.

This prevents a professional contractor from silently carrying out obviously defective instructions and later saying:

“The owner supplied the materials, so it is not my problem.”

Professional contractors are expected to identify relevant technical risks and provide warnings.

How Long Is the Contractor Liable?

Article 478 TCO establishes the principal limitation periods for defect claims arising from contracts for work.

Claims concerning defective work become time-barred from delivery after:

• two years for works other than immovable structures,
• five years for immovable structures,
• and twenty years where the contractor is grossly at fault, regardless of the nature of the work.

For construction projects, the five-year period is therefore particularly important.

But the 20-year rule may become critical in cases involving serious contractor misconduct or grossly defective construction.

The distinction should be understood clearly:

2 years: ordinary non-building works.

5 years: immovable structures.

20 years: where contractor liability involves gross fault.

These periods generally run from delivery, not from the date on which the hidden defect is discovered.

Discovery of the Hidden Defect Does Not Restart the Five-Year Period

This is an important practical point.

Suppose a building is delivered on 1 June 2023.

A hidden construction defect is discovered on 1 June 2027.

The discovery does not ordinarily create a new five-year limitation period beginning in 2027.

Article 478 calculates the ordinary limitation period from delivery.

Therefore, the owner may have relatively little time remaining to pursue the claim even though the defect was discovered only recently.

The owner must simultaneously consider:

the immediate notification requirement under Article 477

and

the limitation period under Article 478.

Ignoring either one can endanger the claim.

Gross Fault Can Extend the Exposure to Twenty Years

The 20-year rule can be extremely important in serious construction cases.

Article 478 expressly provides a 20-year limitation period where the contractor is grossly at fault.

Not every construction mistake constitutes gross fault.

The legal characterization depends on the seriousness of the contractor’s conduct.

Potentially relevant circumstances may include extremely serious disregard of elementary construction requirements, deliberate concealment, knowingly using manifestly unsuitable construction methods or other conduct demonstrating a grave departure from the professional standard expected.

A contractor also cannot validly protect itself in advance against liability for its own gross fault.

Article 115 TCO states that a prior agreement excluding liability for the debtor’s gross fault is absolutely invalid.

Therefore, a clause stating:

“The contractor shall under no circumstances be liable for any construction defect”

should not automatically be assumed to eliminate statutory liability, particularly where gross fault is involved.

Contractual Warranty Periods and Statutory Liability Are Not Always the Same Thing

Construction contracts frequently contain a contractual “warranty period,” such as:

“The contractor warrants all works for two years after provisional acceptance.”

This contractual period must be distinguished from the statutory defect regime.

A contractual warranty may establish additional repair obligations, procedural mechanisms or agreed standards.

However, the existence of a contractual warranty clause does not automatically mean that all statutory rights disappear when that contractual period expires.

The agreement must be interpreted together with the mandatory and general rules of the Turkish Code of Obligations, including the statutory limitation rules and restrictions on exclusion of liability for gross fault.

For major construction contracts, the distinction between:

• defect notification periods,
• contractual warranty periods,
• provisional acceptance,
• final acceptance,
• retention periods,
• and statutory limitation periods

should therefore be expressly analysed.

Consumer Home Buyers May Have Additional Protection

The position may differ where the dispute is not simply between an employer and contractor under a conventional construction agreement but involves a consumer purchasing a newly constructed residence from a commercial developer.

Law No. 6502 on Consumer Protection contains a separate defective-goods regime.

A product may be defective where it lacks contractual qualities or contains material, legal or economic deficiencies reducing the benefits reasonably expected by the consumer. Defects appearing within six months after delivery are presumed to have existed at delivery unless that presumption is incompatible with the nature of the product or defect.

Consumers may, subject to the applicable conditions, choose between:

• termination,
• price reduction,
• free repair,
• and replacement with a defect-free equivalent.

For residential and holiday-purpose immovable property, consumer-law defect claims are generally subject to a five-year period from delivery. Where the defect was concealed through gross fault or fraud, the Consumer Protection Law provides that the limitation provisions do not apply.

Whether the Turkish Code of Obligations or consumer-law regime applies—and how they interact—depends on the legal nature of the particular transaction.

A private landowner hiring a construction contractor and a consumer purchasing a newly built apartment from a developer should not automatically be treated as legally identical situations.

Common Hidden Defects in Construction Litigation

Hidden defect cases frequently concern technically complex failures such as:

Waterproofing Failure

Waterproofing can appear perfectly functional during summer handover but fail during winter rainfall.

The source may be:

• roof membranes,
• terraces,
• basement systems,
• retaining walls,
• window details,
• façade joints,
• or underground waterproofing.

The visible water stain is often only the symptom.

Expert examination is usually necessary to identify the construction defect causing it.

Structural Cracking

Not every crack is a structural defect.

Some cracks may be cosmetic.

Others may indicate:

• excessive settlement,
• structural movement,
• reinforcement problems,
• defective concrete,
• foundation deficiencies,
• or incorrect engineering execution.

The legal classification depends heavily on technical evidence.

Thermal and Acoustic Insulation

Defective insulation may not become apparent until seasonal conditions change or neighbouring units become occupied.

The owner may discover significant energy loss, condensation, mould formation or sound transmission only after prolonged use.

Concealed Plumbing and Mechanical Systems

Pipe connections, drainage slopes, HVAC systems and mechanical installations are often concealed inside walls or floors.

Defects may remain invisible until the system is placed under sustained operational load.

Façade and External Envelope Defects

Poorly installed façade systems may create water ingress, thermal bridges, detached panels or other risks long after initial delivery.

Because these defects often involve inaccessible areas, documenting causation through a technical expert can be decisive.

Evidence Should Be Preserved Before Repair

One of the most common mistakes in construction litigation is repairing the defect first and attempting to prove it later.

Imagine that severe leakage occurs.

The owner immediately removes:

• roof membranes,
• insulation,
• damaged concrete,
• pipes,
• and finishing materials.

The building is then completely repaired.

Six months later, litigation begins.

The contractor argues:

“There was no construction defect. The owner altered the building.”

The owner may now face serious evidentiary difficulties because the original condition no longer exists.

For this reason, where the defect is significant, evidence should ideally be preserved through:

• detailed photographs and video,
• expert reports,
• technical measurements,
• samples where relevant,
• correspondence,
• site records,
• and, where necessary, judicial evidence determination under Articles 400–405 HMK.

Urgent safety works should obviously not be delayed where immediate intervention is necessary, but evidence can often be documented before or during the repair.

A Practical Example

Consider a villa completed and delivered on 15 September 2024.

Nothing unusual is visible during handover.

During severe rainfall in December 2026, significant water enters the basement.

An engineer later identifies that the external waterproofing membrane was improperly installed during construction.

The owner should consider several legal questions:

Was this defect reasonably discoverable at delivery?

Probably not, if the waterproofing was concealed underground.

Is it therefore potentially a hidden defect?

Yes.

What should the owner do after discovery?

Document the problem and notify the contractor without delay under Article 477.

Can the owner demand repair?

Potentially yes, if the contractor is responsible and repair does not require disproportionate expenditure.

Can damages also be claimed for damage to the basement?

Potentially, under Article 475 together with the general damages provisions.

Does the owner have five years from the date of discovering the defect?

No. The ordinary five-year period for an immovable structure runs from delivery.

The owner therefore needs both a technically sound defect investigation and a legally timely response.

What Should an Owner Do Immediately After Discovering a Hidden Defect?

The safest practical sequence is usually:

First, document the defect.

Photograph and record the physical condition.

Second, obtain technical assistance.

Determine whether the problem is likely caused by defective construction rather than ordinary wear, user error or subsequent intervention.

Third, preserve evidence.

Where the defect will disappear during repair, consider an expert report or judicial evidence determination.

Fourth, notify the contractor without delay.

Identify the defect and reserve legal rights.

Fifth, determine the correct remedy.

Repair may be preferable in one case; price reduction, damages or another remedy may be appropriate in another.

Sixth, calculate the limitation period from delivery.

Do not calculate only from discovery of the defect.

Conclusion: A Hidden Defect Is Not the End of the Owner’s Rights—but Delay Can Be

Turkish construction law provides significant protection against defective workmanship.

Under Articles 474–478 TCO, a contractor may remain liable where the completed work contains defects, including defects that could not reasonably have been discovered during the initial inspection.

The owner may potentially seek:

repair,

price reduction,

termination in sufficiently serious cases,

and damages.

But these rights are closely connected with procedural discipline.

Apparent defects must be identified through proper inspection and timely notification.

When a hidden defect appears later, the contractor must be notified without delay. Failure to do so may result in the work being treated as accepted.

At the same time, the general statutory limitation periods must be monitored:

2 years for ordinary works,

5 years for immovable structures,

and 20 years where the contractor is grossly at fault.

The most important lesson is therefore simple:

Do not confuse the warranty period, the defect-notification obligation and the limitation period. They are different legal concepts.

When a serious construction defect appears, the correct legal sequence is:

detect → document → obtain technical evidence → notify → preserve evidence → determine the remedy → act before the applicable limitation period expires.

In construction disputes, a crack, leak or structural deficiency may remain hidden for years.

The owner’s legal rights should not remain hidden with it.