Defective waterproofing in Ibiza villas: how to claim

To prove that waterproofing has been poorly executed in a villa in Ibiza, it is not enough to simply demonstrate the presence of dampness or leaks. A technically sound claim requires identifying the point of water entry, determining the construction cause, relating it to the project, the execution conditions, and the applicable regulations, documenting the damage, and explaining what repairs would be necessary to correct the source of the problem.

In high-value properties, this distinction is especially important. A visible leak in a roof may originate from a roof located several meters away; dampness in a basement may be related to drainage, a wall in contact with the ground, or a construction junction; and a terrace may leak not through the main membrane, but through a drain, a parapet, a joint, or a single point that was incorrectly addressed.

At Optima Pericial we carry out construction expert reports in Ibiza and the Balearic Islands aimed at technically determining the origin of damages, documenting execution defects, assessing their repair and providing an independent report for out-of-court claims, insurance or legal proceedings.

What really needs to be proven in a claim for defective waterproofing

The purpose of an expert report is not merely to demonstrate that "there is water." The report must answer several questions with the greatest possible degree of technical objectivity.

• Where does the damage manifest itself?
• What is the likely path of the water?
• Which structural element has failed?
• Is it a design defect, an execution defect, a product defect, a maintenance defect, or a combination of causes?
• Does the construction match the construction documentation?
• Have the technical conditions of the system used been respected?
• Is there a causal relationship between the defect and the observed injuries?
• What intervention is necessary to properly repair the source?
• What is the reasonable cost of that repair and the resulting damages?

This methodology is the difference between a report that simply describes dampness and an expert opinion capable of technically explaining why it has occurred.

Where do waterproofing failures usually appear in a villa?

Contemporary villas in Ibiza can incorporate particularly complex construction solutions: large terraces, flat roofs, infinity pools, integrated planters, basements, retaining walls, junctions between different materials, and large glazed openings.

That doesn't mean these solutions are bound to fail. It means that the project details and the execution of critical points become absolutely essential.

Flat roofs and terraces

Among the injuries that may warrant an expert investigation are:

• Dampness in ceilings or where they meet facades.
• Persistent puddles.
• Cracks or openings in junctions and breastplates.
• Pavement detachments or lifting.
• Leaks near drains.
• Damage around facility steps.
• Joint degradation.

Insufficient slope, a poorly designed drain, or a discontinuity in the waterproofing at a junction can cause damage even if most of the membrane is correctly installed.

Basements and walls in contact with the ground

In buried areas, different phenomena must be distinguished: leaks, moisture from the ground, drainage failures, condensation, and possible capillary rises.

Therefore, a stain on a basement wall alone does not allow us to conclude that the exterior membrane is defective. The expert must analyze the geometry, the terrain, the construction solution, the drainage, the wall-slab junctions, and the evolution of the damage.

Swimming pools, basins, canals and adjacent areas

In a high-end villa there may be infinity pools, spas, reservoirs, water features or terraces directly related to these elements.

When losses or leaks occur, a distinction must be made between:

• Glass defects.
• Problems in installation steps.
• Joint failures.
• Hydraulic losses.
• Waterproofing defects in adjacent areas.
• Problems in channels or overflows.

Attributing the cause without separating these possibilities can lead to a costly repair that does not solve the problem.

Facades, openings and meeting points

On facades, problems can be related to the cladding, the main leaf, junctions with joinery, sills, copings, joints or finishing touches.

The DB HS 1 Protection against humidity of the Technical Building Code specifically addresses design and execution conditions relating to walls, floors, facades and roofs, as well as their singular points.

How an expert investigates a poorly executed waterproofing project

The expert report must be tailored to the building and the causal hypothesis. There is no single test capable of resolving all cases.

Visual inspection and injury assessment

The first phase consists of inspecting both the areas where the damage appears and the structural elements that could cause it.

Location, extent, morphology, fissures, detachments, efflorescence, deformations, joints, junctions, slopes and other relevant evidence are documented.

Technical photography is important, but a single photograph does not, on its own, establish the cause of action. Its value increases when it is part of a structured analysis that links each image to the location, date, injury, and corresponding technical conclusion.

Humidity measurements

Measuring equipment can help map affected areas, compare areas, and track the evolution of the damage.

However, there is no single "moisture percentage" that automatically indicates waterproofing failure. The results depend on the material, equipment, methodology, and inspection conditions.

Therefore, the measurements must be interpreted in conjunction with the rest of the evidence.

Infrared thermography

Thermography can be useful for locating thermal anomalies consistent with humidity differences, thermal bridges, or other phenomena.

However, a thermal image alone does not identify water or automatically prove a leak. It must be interpreted considering environmental conditions, solar radiation, geometry, materials, and other possible causes of thermal contrast.

When used correctly within an expert protocol, it can be a very valuable support tool.

Leak tests

When technically appropriate, leak tests can help reproduce exposure conditions and check whether an item allows water to pass through.

The test must be designed for the specific item, control the test conditions, and avoid creating new damage or unnecessarily altering existing evidence.

In certain cases it will be more appropriate to divide the area into sectors, test specific points, or use other techniques rather than flooding an entire surface.

Selective destructive testing and inspection

When non-destructive techniques do not allow us to know how a hidden solution was implemented, it may be necessary to carry out localized testing.

A selective opening can allow you to check:

• The actual existence of the planned membrane.
• Its continuity.
• Overlaps.
• Adherence.
• Protection.
• Encounters with walls.
• Slope formation layers.
• Solutions around drains or installations.

In a relevant conflict, the location and documentation of the test pits must be carefully planned to preserve their traceability.

Comparing what has been built with the project is one of the most important tests

The physical inspection must be complemented with the documentary analysis.

Depending on what exists, the expert may review:

• Basic project and execution project.
• Construction details.
• Memoirs and documents.
• Project modifications.
• Book of orders and attendance.
• Work certifications.
• Final construction documentation.
• Product data sheets and performance declarations.
• Manufacturer's installation instructions.
• Photographs taken during construction.
• Budgets, contracts and measurements.
• Communications between property owner, construction company and project management team.

CTE DB HS 1: protection against humidity

The Basic Document HS, section HS 1 Protection against moisture, is an essential reference in the analysis of numerous watertightness defects.

Its scope includes, among other elements, walls and floors in contact with the ground, facades, and roofs. It also regulates conditions relating to critical points and solutions for protecting against water penetration.

However, the expert report should not be limited to locating a section of the CTE (Technical Building Code) and stating that there is non-compliance. It must verify which regulatory version was applicable to the project and the work, what solution was planned, and how it was actually implemented.

Manufacturer's specifications and technical standards

In industrialized systems or specific products, the installation instructions can be essential to assess the execution.

UNE standards or other technical specifications may also be relevant when they are applicable to the system, incorporated into the project, or allow for the assessment of the technical execution rules.

The relevance of each reference must be justified for the specific case; not every technical standard mentioned in a report is automatically mandatory.

How is the causal link between the defect and the leak demonstrated?

This is the core of a good expert report.

A report must construct a technically coherent sequence:

1. There is an objectively documented injury.
2. The related construction element is identified.
3. A design, execution, product, or conservation anomaly is detected.
4. Reasonable alternative causes are ruled out or considered.
5. The anomaly explains in a technically consistent way the path and characteristics of the damage.
6. The proposed repair addresses the cause and not just the deteriorated finish.

The better this chain is explained, the harder it is to reduce the conflict to opposing statements such as "it's a lack of maintenance" versus "it's poor execution".

Defective waterproofing and the Building Regulations Act

When the damages arise from the construction process, one of the essential rules is Law 38/1999, of November 5, on Building Regulations (LOE).

The LOE establishes responsibilities of the agents involved in the building for certain material damages that manifest themselves within different periods counted from the receipt of the work without reservations or from the correction of these.

A leak does not automatically fall within the three-year period

Waterproofing defects are frequently related to habitability, especially when they compromise protection against moisture.

However, the specific legal classification depends on the material damage and its extent. A temporary label should not be automatically applied without analyzing the case.

Similarly, the presence of dampness in a structural element does not automatically qualify the case as a ten-year defect. For the ten-year warranty period stipulated by the Spanish Building Regulations (LOE), the defect must affect the structural elements specified by law and directly compromise the building's mechanical resistance and stability.

The two-year statute of limitations is not simply counted from "when you discover" the damage

Article 18 of the LOE establishes that actions to demand the liability provided for in its article 17 for material damages prescribe two years after the damages occur.

This clarification is important because the 1, 3 or 10 year period in Article 17 and the 2 year period in Article 18 serve different purposes.

For this reason, in cases of significant damage, we do not recommend calculating timeframes solely from the date the owner remembers first noticing a stain. The chronology should be reconstructed using documentation and reviewed with legal advice.

Who can be held responsible for poorly executed waterproofing?

The LOE is based on the personal and individualized responsibility of each agent for their own acts or omissions and for those for whom they must legally answer.

The specific attribution must be based on the technical cause of the damage.

Builder

The builder must carry out the work in accordance with the project, the applicable legislation and the instructions of the project management team.

The LOE also establishes that it is directly responsible for certain damages arising from persons dependent on it and from parts of the work that it subcontracts, without prejudice to any recourse actions that may be appropriate.

If the defect stems from incorrect execution of the waterproofing, joints, overlaps, supports or elements installed by the builder or their subcontractors, their involvement will be one of the aspects to be analyzed.

Construction Manager

The project manager directs the development of the work in its technical, aesthetic, urban planning and environmental aspects in accordance with the project, the license and the conditions of the contract.

The project manager should not be automatically held responsible for any construction defects. The expert report must examine their responsibilities, the decisions made, any modifications made, and the specific relationship between their actions or omissions and the damage.

Project Manager

The LOE assigns to the director of execution the technical function of directing the material execution and controlling qualitatively and quantitatively the construction and the quality of what is built.

Among their obligations is checking materials, correct execution and arrangement of construction elements and installations according to the project and the instructions of the project manager.

Designer

If the origin lies in an insufficient, incompatible, incomplete or incorrectly defined waterproofing solution in the project, the potential responsibility corresponding to the project must be analyzed.

Promoter

The LOE establishes that, in the face of potential purchasers, the developer is jointly liable with the other intervening agents for material damages to the building caused by defects or flaws in construction, under the terms of the law itself.

Joint and several liability when the cause cannot be individualized

When the cause of the damages cannot be individualized or there is concurrence of faults without the degree of intervention of each agent being able to be specified, the LOE contemplates joint and several liability.

For this very reason, the expert report must avoid generic attributions and explain what evidence exists regarding each possible participant.

What happens if you bought the villa and the defect already existed?

In a villa that has already been acquired, it may be necessary to analyze, in addition to the LOE (Law on Building Regulations), the actions derived from the purchase agreement and the regime of hidden defects.

Article 17.9 of the LOE itself expressly leaves the seller's responsibilities towards the buyer in accordance with the contract, Articles 1484 et seq. of the Civil Code and the rest of the applicable legislation.

The Civil Code regulates the remedy for hidden defects that render the item unfit for its intended use or significantly reduce its usability. The specific actions outlined in Articles 1484 to 1489 have, according to Article 1490, a limitation period of six months from delivery.

This does not mean that all disputes arising from defects in a villa must be pursued through this channel, nor that, once this deadline has passed, any possible legal action necessarily disappears. The contract, the Building Regulations (LOE), the status of the parties, and the nature of the breach may open up different avenues that a lawyer should assess.

Ten-year insurance: when can it intervene

The so-called ten-year insurance refers to the ten-year guarantee against material damage caused by vices or defects that affect certain structural elements and directly compromise mechanical resistance and stability.

The second additional provision of the LOE establishes this guarantee as mandatory for buildings whose main purpose is housing, with the exceptions provided for by law, including certain cases of individual self-promotion of single-family housing for own use.

Therefore, a leak in a roof or terrace is not covered by the ten-year structural warranty simply because it is a construction defect. The policy, the damage, its origin, and whether the structural coverage requirements are met must be verified.

How to prepare a claim for defective waterproofing

1. Document the damage before altering the area

It is advisable to keep photographs, videos, dates of rain events, communications, budgets and any information about the evolution of the injuries.

If there is a risk of the situation worsening or of harm to people or property, urgent action may be necessary. In such cases, it is especially important to document the existing condition beforehand, to the extent possible, and to maintain traceability of any modifications made.

2. Obtain an independent expert opinion

Before discussing only amounts, it is necessary to establish what is failing and why.

The report should allow differentiation between a superficial solution and a technically adequate repair of the source.

3. Identify the legal avenue and those responsible

With the technical cause defined, the lawyer can analyze whether the claim should be directed against the builder, developer, technicians, seller, insurer or other parties and what action is applicable.

4. Make the out-of-court claim with time limits controlled

Article 1973 of the Civil Code establishes that prescription may be interrupted by the exercise of the action before the courts, by extrajudicial claim of the creditor or by acknowledgment of the debt by the debtor.

In practice, the claim must be carefully prepared, addressed to the appropriate party, and be properly documented. In important matters, we recommend coordinating its drafting and legal implications with the attorney handling the case.

5. Negotiation, mediation, insurance or legal proceedings

A solid expert opinion can be used to negotiate a settlement, evaluate an offer, respond to a contrary report, or support a legal claim.

If the matter goes to trial, the Civil Procedure Law allows for the submission of expert reports when technical knowledge is necessary to assess relevant facts. The expert may subsequently appear to explain the report and answer questions admitted by the court.

What should a waterproofing expert report include?

The content depends on the assignment, but a solid report is usually structured around the following elements:

1. Object and scope: what technical questions must the expert answer.
2. Property identification: location, areas inspected and relevant background.
3. Documentation analyzed: project, contracts, photographs, previous reports and other background information.
4. Methodology: inspections, measurements, tests and limitations of the work.
5. Description of damages: location and characteristics of each injury.
6. Constructive analysis: configuration of related elements.
7. Causal analysis: technical explanation of the origin and reasoned elimination of alternatives.
8. Applicable regulations and technical documentation: CTE, project, specifications and other relevant references.
9. Repair solution: actions necessary to correct the cause.
10. Economic valuation: when it is part of the order, justified quantification of the repair and associated damages.
11. Conclusions: clear answers to the expert questions raised.

Objectivity of the expert

The expert's role is not to defend a particular version of events at any cost. Article 335 of the Civil Procedure Law requires the expert to declare that they have acted and will act with the greatest possible objectivity, considering both what may favor and what may harm either party.

For a high-value property, this independence is essential: a technically exaggerated report can be just as detrimental to a claim as an insufficient one.

How is the damage valued economically?

The amount of a claim should not be set by a generic range per square meter without studying the construction.

In a villa, properly repairing waterproofing may require:

• Preliminary demolitions and dismantling.
• Removal and management of materials.
• Opening of hidden areas.
• Slope reconstruction.
• New waterproofing.
• Treatment of singular points.
• Replacement of stone, ceramic or other finishes.
• Repair of false ceilings and interior cladding.
• Interventions on affected facilities.
• Auxiliary means, access and protections.
• Subsequent control tests.

In properties with unique finishes, natural stone, special woodwork or high-level interior spaces, the indirect cost of accessing the origin of the defect can far exceed that of the waterproofing membrane.

Associated damages and loss of use

When legally claimable and can be proven, the valuation may require analyzing other damages related to the harm, such as replacement of finishes, affected furniture, loss of use or income and other economic consequences.

The inclusion of each concept must be justified by documentation and coordinated with the legal strategy of the claim.

Mistakes that can weaken a claim

Repair completely before documenting

Removing faulty waterproofing can make it impossible to verify how it was actually installed. Whenever the urgency allows, it's advisable to document and have it assessed before concealing the evidence.

Assuming that all moisture comes from waterproofing

Condensation, leaks in installations, drainage, capillary action, or facade defects can produce similar symptoms. A premature conclusion makes it easier for the opposing party to challenge the entire report.

Confusing the cost of patching with the cost of repairing

Sealing a joint or painting over a stain may temporarily reduce the symptom but not resolve the underlying cause. The expert assessment must distinguish between a temporary measure and a technically sound repair.

To accept without question the cause proposed by the insurer or the construction company

A report from another party is a source of information, but it does not replace an independent assessment when there is a relevant economic conflict.

Misapplying the LOE deadlines

One of the most dangerous mistakes is adding "three years warranty plus two years to claim" as if it always worked automatically that way.

The LOE requires analyzing when the work was received, within what period the damage occurred and when the statute of limitations for the specific action began to run.

Why choose Optima Pericial for a villa in Ibiza?

A construction problem in a high-value property requires an intervention proportionate to the economic risk of the matter.

At Optima Pericial we approach these cases from three objectives:

• Diagnosis: determining what is really failing.
• Evidence: document the facts and their technical cause in a traceable manner.
• Valuation: define what repair the property needs and quantify it where appropriate.

We can intervene before a claim is made, review reports from builders or insurers, conduct counter-expertise, provide expert opinions, and collaborate technically with the lawyer handling the case.

In villas with complex interventions, our goal is for the owner to be able to make decisions based on technical evidence and not on conflicting versions.