By “vertical extension” we mean the construction of a new floor (or floors) on top of an existing building. This can apply to detached houses, two-storey homes, and apartment buildings, where additional ownership and rights issues often arise. In most cases, a Building Permit is required, and the process is submitted electronically through the e-Permits system.

What “allowed” really means in a vertical extension

When someone asks, “Am I allowed to build a vertical extension?”, they are essentially asking three questions at once. First, whether the area’s planning rules allow additional height or more square meters. Second, whether the existing building is lawful and the documentation is clear, so the permit file can move forward without obstacles. And third, whether the building can technically cope—not only with the weight of a new floor, but also with the impact such a change has on the building’s overall seismic behavior.

The legal framework for general building rules is the New Building Regulation (NOK), together with any special provisions that apply locally. This matters in practice: two properties that look similar can be subject to completely different restrictions, depending on their location and the regulations in force there.

When a vertical extension may be possible

Usually, feasibility starts with a basic question: has the permitted building capacity and height already been exhausted? In many cases—especially with older buildings or plots that were never fully utilized—there may be remaining “allowance” that could enable an additional floor. That doesn’t mean you automatically proceed. It means it’s worth carrying out a serious, structured assessment.

At the same time, you must rule out cases where special restrictions apply. In certain areas or within specific planning frameworks, there may be constraints that directly affect licensing. For example, there are situations where, due to special provisions (such as planned arcades that have not been opened), a building permit is not granted for any kind of extension. That is why the evaluation cannot be based on assumptions or a general impression. It must be grounded in the actual data of the property.

Another point that often comes up is whether an extension can follow the existing building outline. In some cases, it is stated that a vertical extension to a lawfully existing building may extend up to its existing footprint, under specific conditions and provided no special provisions prohibit it. This is an area that requires careful attention: it is not a “rule for everyone.” It is assessed based on the facts and the regulations applicable to each individual case.

What the engineer checks before any design work begins

The right starting point is not to immediately design the new floor. The right starting point is to confirm whether there is a clear path to obtaining a permit and whether the solution can stand safely.

The planning assessment is the first link in the chain. The engineer checks what is permitted for the specific plot: allowable height, allowable floor area, distance requirements, and any special local terms. This clarifies the “can we” and the “up to what limit” before time is spent on drawings that may not be licensable.

Next comes verification of the existing building. Many properties—especially older ones—have discrepancies between plans and reality or missing elements in older permit files. If these issues are not addressed early, the process can slow down or become blocked later. For this reason, a proper survey is carried out, documentation is reviewed, and a clear picture is formed of what is lawful, what is recorded, and what may require correction or regularization.

The most critical evaluation, however, is structural. A vertical extension effectively changes the building: it introduces new loads, alters mass distribution, and in many cases changes the way the structure responds during an earthquake. The structural engineer assesses the load-bearing system and foundations, examines the building’s condition (wear, defects, cracking), and determines whether the building can support the extension as it is or whether strengthening is required. In Greece, assessment of existing structures is linked to the KAN.EPE. framework (Regulation for Interventions).

This is often the point where the entire picture changes. In many cases, the right solution is not simply “build one more floor,” but “build one more floor and strengthen the structure where needed,” so the result is genuinely safe and technically justified.

What permit is required—and why it’s not a “quick” process

For a vertical extension, the process is completed through a Building Permit and includes the required studies (architectural, structural, and any other studies needed depending on the case). Submission and issuance are carried out through the e-Permits system.

If someone is looking for a “quick fix,” they may be disappointed—not because it’s impossible, but because a properly executed vertical extension must rest on two foundations: it must be legal and it must be safe. When the right steps are taken from the beginning, the project moves forward more smoothly and unpleasant surprises are avoided.

Common questions

The right first step

If you are considering a vertical extension, the best first step is a preliminary assessment: what is allowed under planning rules, what the legal status of the existing building shows, and what the first structural picture looks like. This gives you a clear answer on whether it is worth proceeding to full design work—and what the safe, realistic plan should be.

If you wish, we can review your property’s information, confirm what is permitted, and outline the steps required, so you can move forward with confidence and without unnecessary delays.

The post Vertical Extension: When It’s Allowed and What an Engineer Checks appeared first on Katsouris Engineering.

In practice, a proper inspection protects you from unpleasant surprises: hidden defects, moisture problems that make fresh paint bubble after a few months, rough or unprofessional alterations to walls, outdated electrical systems, as well as legal-compliance issues that can delay the transfer or complicate a future resale.

What is a technical inspection and why is it worth it?

A technical inspection is a structured process carried out by an engineer to assess a property’s condition. It’s not limited to “checking for cracks”. The goal is to determine:

• whether the property is safe and in good technical condition,
• whether there are issues that require immediate repair or monitoring,
• whether renovation/restoration costs may be higher than expected,
• whether there are illegal modifications or deviations that could cause problems.

Most importantly, a technical inspection helps you make a decision based on facts—not just on appearance. This usually means better negotiation, better planning, and often significant financial savings.

What does a complete technical inspection include?

Every property is different. A third-floor apartment has different needs than an older detached house or a commercial space. However, a complete inspection typically covers the following.

1) On-site inspection and overall technical condition

The process starts with an on-site visit. The engineer evaluates the property as a whole: walls, ceilings, floors, windows/doors, visible defects, and signs that may indicate underlying issues.

At this stage, problems may appear that most buyers don’t easily notice, such as:

• minor changes in corners that suggest moisture,
• freshly painted areas that may be covering stains,
• workmanship issues that point to quick, low-quality repairs.

The goal is not to “find faults”, but to clearly capture the property’s condition as it is today.

2) Structural condition and load-bearing system

One of the most important parts is assessing the building’s structural condition. Here, the engineer looks for signs that may indicate stress or past failures, such as:

• cracks (where they appear, their shape, whether they seem active),
• deformations, tilts, or settlement indicators,
• signs of corrosion/deterioration in visible elements,
• alterations made without proper design (e.g., openings in walls, layout changes).

It’s important to say this clearly: not all cracks are dangerous. Many are superficial or due to thermal movement. However, experience is needed to distinguish what is “minor” from what requires further investigation.

If necessary, the inspection may lead to the next step: a structural adequacy assessment or recommendations for structural strengthening, especially for older buildings or properties with significant alterations.

3) Moisture, waterproofing, and “hidden” costly issues

Moisture problems are among the most common—and the most deceptive. A home may look “perfect” during a viewing, yet after the first winter, mold or discoloration can appear.

During the inspection, the engineer checks for:

• mold/stain signs on walls and ceilings,
• salt deposits or plaster blistering,
• issues on terraces, balconies, roofs, gutters,
• possible plumbing leaks or poor stormwater drainage.

In many cases, moisture isn’t just “a paint job”. It can require waterproofing, insulation repairs, and works that significantly increase the budget.

4) Systems inspection: electrical, plumbing, heating/cooling

Even if you love the property, the functionality and safety of the installations are critical. The inspection evaluates the condition of:

• electrical systems (panel, breakers/fuses, grounding where feasible, overall age of the network),
• plumbing (leaks, pressure, signs of old piping),
• heating/air-conditioning (unit condition, proper operation, general system image).

Especially in older properties, installations may need upgrades to meet modern needs. Knowing this before you buy is essential.

5) Legal compliance and planning/permit condition

This is where many purchases “get stuck” at the last moment. A property may have layout changes, enclosed balconies, change of use, or deviations from the original permit.

A technical inspection can help identify:

• suspicious differences from the original layout,
• alterations that appear to have been done later,
• the need for further file/document review.

Compliance is not only about the transfer. It affects the future as well: renovation, financing, resale, or rental/usage potential.

How the process works, step by step

Typically, the process follows a clear sequence:

1. Discussion of your needs (what you’re buying, what for, what concerns you)
2. On-site inspection with checks of key points
3. Recording findings and photo documentation where needed
4. Estimating risks and possible works
5. Technical report with conclusions and next-step recommendations

This gives you a practical result that supports both your decision and negotiation.

“Red flags” you shouldn’t ignore

Some signs deserve extra attention:

• cracks appearing in multiple areas or with a “structural” pattern
• strong moisture in ceilings/corners, especially with odor
• patch repairs and repainting in specific areas (as if covering something)
• very old installations with no clear safety picture
• layout changes that seem unplanned

This doesn’t automatically rule out buying. It means you should know exactly what it implies.

A technical inspection before buying a property is the smartest move to protect your investment. It gives you a clear picture, reduces risk, and helps you move forward confidently—whether you decide to buy or to look for a better option.

If you’re considering a purchase and want a documented, engineer-led view before proceeding, Katsouris Engineering can handle the inspection with an on-site visit, evaluation of findings, and practical recommendations for the next steps.

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It is the building’s structural skeleton—the system that keeps it standing and allows it to withstand loads, everyday use, the passage of time, and, especially in Greece, seismic activity. Without a properly designed and constructed structural system, no property can be considered truly safe, regardless of how modern or well-maintained it may appear.

In this article, we explain what a building’s structural system is, which elements it consists of, and why it plays a critical role in property transfers, legalization procedures, and technical inspections.

What Is a Building’s Structural System

A building’s structural system is the set of structural elements responsible for safely transferring all loads from the building to the ground. It is not a single component, but an integrated system that functions as a whole.

Through this system, the building’s own weight, furniture, occupants, and external forces such as wind and earthquakes are transferred in a controlled manner to the foundations.

If a building were a human body, the structural system would be its skeleton. Without it, no building can stand, endure over time, or function safely.

Main Components of the Structural System

In most modern buildings, the structural system consists of several elements that work together as a unified framework.

Columns transfer vertical loads from the floors down to the foundations. Beams connect the columns and distribute loads horizontally, ensuring the structural continuity of the frame. Slabs—floors and roofs—collect loads from the building’s use and transfer them to the beams and columns.

All these loads ultimately reach the foundations, whose role is to safely transfer them to the ground. In certain cases, especially in steel structures, bracing systems or diagonal members are also used to enhance stability against horizontal forces such as wind and seismic actions.

In older buildings, particularly those constructed before the widespread use of reinforced concrete, load-bearing masonry is commonly found. In these structures, walls do not merely act as partitions but actively participate in the building’s structural behavior. For this reason, any intervention in such properties requires special care and prior technical evaluation by an engineer.

Materials Used in Structural Systems

A building’s structural system can be constructed using different materials, depending on the building’s use, size, strength requirements, and environmental conditions.

In Greece, the most common type of structural system is reinforced concrete. When properly designed and constructed, it can safely withstand building loads and seismic forces throughout the building’s lifespan. Concrete works together with steel reinforcement, forming a system that combines stiffness with controlled deformation—an especially important characteristic for seismic performance.

In certain projects, mainly commercial, industrial, or specialized buildings, structural steel is used. Steel structures allow for faster construction and lower overall weight. In many cases, composite systems are applied, combining concrete and steel to take advantage of both materials.

In all cases, a critical role is played by the reinforcing steel—the metal elements embedded within the concrete that enable it to perform safely under loads and seismic stresses. Proper placement and detailing of reinforcement are essential for the overall strength and reliability of the structural system.

Load-Bearing vs. Non-Load-Bearing Elements

One of the most common misconceptions in buildings is the belief that all walls or structural elements can be modified without consequences. In reality, there is a fundamental distinction between load-bearing and non-load-bearing elements, which directly affects building safety.

Non-load-bearing elements, such as lightweight partitions, do not participate in the structural behavior of the building and mainly serve functional or architectural purposes. Load-bearing elements, on the other hand, are part of the structural framework and actively contribute to transferring loads to the foundations.

Removing or altering a load-bearing element—even if it appears minor or harmless—can seriously affect the building’s stability and performance. For this reason, any intervention should always be preceded by an engineer’s assessment to determine whether an element is load-bearing or not.

The construction of the structural system is one of the most critical stages of any project. Errors at this stage are difficult to correct later and affect the building’s performance throughout its entire lifespan. Additionally, many properties have undergone past interventions without proper studies or permits, such as large openings in walls or removal of structural elements for aesthetic reasons.

Even changes in use or the addition of new loads can make a structural assessment necessary, to verify whether the existing system can safely meet the new demands.

When Structural Problems Appear and Why They Affect Legality

Problems in a building’s structural system are not always immediately visible. In many cases, they develop gradually, appearing as cracks, deformations, or settlements—either due to seismic activity or the natural aging of materials over time.

This is particularly common in older buildings, where technical documentation may be incomplete or unauthorized interventions may have taken place. In such cases, structural assessment becomes necessary, especially during legalization procedures, changes of use, or when issuing the Electronic Building Identity.

The structural system is directly linked to a property’s legal status. During property transfers, unauthorized construction legalization, or evaluations by public authorities, it is examined whether any interventions affect structural safety. Even interventions carried out many years ago may be reassessed if they are considered to alter the building’s structural behavior.

In these situations, a structural adequacy study may be required to demonstrate that the building remains safe and functional. Without proper technical documentation, procedures are often delayed or cannot be completed.

What This Means in Practice for Property Owners

For property owners, the structural system is not just a technical term. It is the factor that determines whether a property can be used, transferred, or upgraded without risk.

Early structural assessment is not an obstacle—it is a tool that protects both safety and property value. In many cases, the evaluation confirms that the building is structurally adequate and no interventions are required, offering owners confidence, transparency, and a smooth progression of any legal or technical process.

The post Building Structural System: What It Is and Why It Matters appeared first on Katsouris Engineering.

In this article, we explain in simple terms:

• when Eurocodes apply,
• when KAN.EPE. is required,
• and what all this means in practical terms for a property owner.

When Property Owners Encounter the Eurocodes

Eurocodes do not apply only to large apartment buildings or public projects. In reality, property owners encounter them much more often than they might expect.

Whenever a new building, an additional floor, or a residential extension is designed, the load-bearing structure must be studied according to the applicable Eurocodes. These standards define how loads are distributed, how a building behaves during an earthquake, and how construction materials work together.

In simple terms, Eurocodes answer the question: “How should a building be designed today in order to be safe?”

Learn more about structural design for new buildings

Why Older Buildings Require a Different Approach

Most buildings in Greece were constructed in different periods, under older regulations or with incomplete technical documentation. Many have undergone modifications, while others have been affected by earthquakes or natural material ageing.

In such cases, applying the rules used for new construction is not sufficient. An existing building has a “history” that must be assessed on its own terms.

This is precisely why KAN.EPE. exists—it focuses exclusively on the safety assessment of existing structures.

What KAN.EPE. Is and What It Examines in Practice

KAN.EPE. (Greek Code for Structural Interventions) works like a health check for a building. It does not assess how the structure should have been built, but how it behaves today and whether it can continue to be used safely.

The engineer documents the building’s geometry, examines construction materials, and evaluates its seismic performance. If weaknesses are identified, technical solutions or strengthening interventions are proposed—only where they are truly necessary.

A structural adequacy assessment is commonly required in cases such as:

• older buildings without a complete technical file,
• regularisation of unauthorised constructions,
• changes of use,
• completion of the Building Identity File.

Learn more about structural adequacy studies for existing buildings

Eurocodes and KAN.EPE.: How They Work Together in Practice

Although these are different regulatory frameworks, they often work together in real projects. For example, when an additional floor is added to an existing building, the existing structure is assessed under KAN.EPE., while the new construction is designed according to the Eurocodes.

Their correct application requires experience and a comprehensive understanding of the project. There is no single solution for every property – each case must be evaluated individually.

When Laws and Authorities Require Them

These regulations are closely linked to:

• Law 4495/2017,
• regularisation of unauthorised buildings,
• the Building Identity File,
• property transfers and changes of use.

In older properties where no technical file exists, a new survey or a structural adequacy study may be required in order to document the safety of the load-bearing structure before any procedure can be completed.

What This Means in Practice for Property Owners

For property owners, the key question is simple: Can I use or transfer my property without risk?

The answer depends on whether the structural condition has been properly assessed and the appropriate regulations have been applied. Those who start the process early avoid delays, additional costs, and unpleasant surprises.

Structural assessment is not an obstacle—it is a tool that protects both safety and property value.

Frequently Asked Questions (FAQ)

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Each type of event affects a building’s structure and materials in different ways, creating damage that is not always immediately visible. Over time, however, these effects can evolve into serious problems. Understanding how extreme weather impacts a building helps property owners identify early warning signs, avoid costly repairs and maintain overall safety.

Heatwaves: silent thermal stress on building materials

High temperatures do more than make indoor spaces uncomfortable. The entire building envelope is constantly expanding and contracting in response to extreme heat.

Materials such as concrete and metal respond to heat by expanding and shrinking, creating micro-movements across the structure. Over time, these movements can lead to fine cracks. On exterior surfaces with insufficient insulation, these cracks can become more pronounced, allowing moisture to penetrate the building and accelerate deterioration.

With prolonged exposure, heatwave stress can:

• cause fine cracking
• weaken insulation layers
• allow moisture infiltration
• make indoor temperature control more difficult

Heatwaves also affect mechanical and electrical systems, which operate under greater strain to cool the interior, resulting in faster wear and reduced efficiency.

Flooding and heavy rainfall: water damage to the envelope and foundations

Water is one of the most damaging forces a building can face. It can infiltrate almost any part of the structure – walls, floors, basements and foundations – often quietly and gradually.

When the soil surrounding the foundations becomes saturated, it loses part of its load-bearing capacity. This can lead to minor or significant settlement of the building. Moisture entering walls and floors can cause plaster detachment, mould growth and deterioration of wooden elements. In many cases, it also damages electrical installations, boilers and heating or cooling systems.

Typical consequences include:

• undermined foundations and settlement
• peeling or blistering paint, plaster detachment and damp surfaces
• mould formation and damage to wood due to trapped moisture
• electrical and mechanical failures after exposure to water

A common symptom is moisture-related cracking: fine lines that initially appear harmless but indicate that water has found a pathway into the building envelope.

Strong winds and storms: mechanical stress on the building envelope

Storms and high winds exert significant pressure on the exterior of a building.

Roofs are often the first elements to be affected: tiles may shift, waterproofing layers can detach, and metal fasteners may loosen. Window frames undergo lateral pressure, and glazing is at risk of breaking during severe weather.

Falling objects – trees, signs or debris from neighboring buildings – can also cause immediate mechanical damage. Even when the damage appears minor, the structural components may have experienced stress that creates weak points requiring inspection.

Wildfires: direct destruction and thermal degradation

Wildfires affect buildings in two ways:
through direct burning of materials, and through thermal degradation, even when the structure does not burn completely.

Reinforced concrete, for example, loses part of its strength after prolonged exposure to high temperatures. Frames, insulation, and finishes can deform or melt, while thermal stress leaves behind microdamage that requires professional assessment.

Even without complete structural loss:

• concrete strength may be reduced
• steel reinforcement can suffer thermal fatigue
• windows, frames and insulation may warp
• microcracks may form, allowing future moisture ingress

Many of these defects are invisible without a detailed technical inspection.

What this means for property owners

Extreme weather affects much more than the appearance of a building. Over time, it can alter its structural behavior, increase indoor humidity levels, reduce energy performance and – in severe cases – pose risks to occupants.

Signs that should not be ignored:

• cracks that appear or grow after bad weather
• blistering, peeling or detached plaster
• damp walls, ceilings or floors
• musty odours or visible mould
• misaligned doors or windows
• damage to the roof or gutters

In such cases, a structural assessment or building pathology inspection is the safest way to determine the extent of the damage.

The need for more resilient buildings

As climate change intensifies weather patterns, building resilience becomes increasingly important.

Modern interventions can significantly reduce the impact of extreme weather events:

• improved thermal and waterproofing systems
• roof reconstruction or reinforcement
• upgraded frames and glazing
• proper rainwater management
• passive design strategies and shading
• structural assessment and strengthening where necessary

Prevention is always more cost-effective than repair.

Frequently Asked Questions (FAQ)

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“Is this something minor, or is it a sign of a deeper problem in the building?”

The truth is that not all cracks are the same. Many are superficial and harmless. Others, however, indicate that the building may require technical assessment, because behind an “innocent” line there may be settlement, moisture penetration, reinforcement corrosion, or structural stress.

The purpose of this guide is to help homeowners understand which cracks require only simple repair – and when a professional evaluation is necessary.

Why do cracks appear on walls?

Cracks are a natural result of how building materials behave over time. Plaster, concrete and masonry are affected by temperature changes, humidity, aging, and even small ground movements. In new buildings, it is common to see fine lines during the first months of occupancy, as materials stabilize and shrink slightly.

In older constructions, cracks may be related to wear, outdated repairs, moisture issues, or natural micro-movements within the structure as it ages.

The key factor is diagnosing the cause – not merely observing the crack itself.

When is a crack harmless?

Many cracks have no impact on the structural safety of a building and concern only the plaster layer or paint. Typical harmless cases include:

• Thin, surface-level cracks that resemble pencil lines.
• Cracks around window frames caused by expansion and contraction.
• Marks that appear after painting or thermal changes.
• Small cracks in drywall due to normal material movement.

As long as these cracks do not increase in width or length over time and do not occur on structural elements, they are considered low risk and can be repaired easily.

When does a crack require technical inspection?

Some cracks indicate that the structure has undergone more significant changes. They may be associated with settlement, wall displacement, reinforcement corrosion or seismic activity.

A professional assessment is recommended when:

• The crack is diagonal or appears near corners of window/door frames.
• The width exceeds 3 mm.
• The crack reappears after superficial repair.
• There is plaster detachment or visible moisture staining.
• There is rust or concrete deterioration near structural elements.
• The crack appeared after an earthquake.
• Other symptoms are present, such as doors that do not close properly or sloping floors.

A crack of this type does not automatically mean the building is unsafe, but it is a clear indication that the cause must be investigated before any repair takes place.

What does an engineer check when assessing a crack?

A technical inspection begins with a detailed recording of the crack: its shape, direction, depth and exact position are essential indicators. The morphology of the crack often reveals whether it originates from the plaster, the masonry, or from changes affecting the structural system.

The wider surrounding area is also examined for signs such as moisture, minor settlements, distorted window frames or localized detachment of plaster. These observations help form a comprehensive understanding of the building’s behaviour.

If there is evidence that the issue extends beneath the plaster layer, non-destructive testing (NDT) methods may be used, including:

• endoscopic inspection of reinforcement,
• moisture measurements,
• concrete hardness testing,
• ultrasonic scanning to detect voids.

If it becomes clear that a crack is linked to a structural element, a focused structural evaluation follows, and appropriate repair or strengthening measures are proposed. The process concludes with clear technical documentation so the property owner knows precisely the condition of the building and the recommended next steps.

When can I repair a crack myself — and when not?

Surface-level cracks, which are purely aesthetic, can indeed be repaired with filler and paint. These cracks usually have no depth and do not affect the underlying structure.

However, this approach should not be used in every case. If the crack:

• increases over time,
• shows measurable depth,
• has a diagonal direction,
• causes material detachment,
• appears on a beam, column or other load-bearing element,

…then a superficial repair merely hides the symptom. The underlying issue remains and often progresses.

A simple rule of thumb: Stable, surface cracks → can be repaired. Cracks that evolve or relate to structural elements → require evaluation by an engineer.

Cracks are common in buildings and are not all dangerous. Distinguishing between a superficial issue and a structural concern is crucial. In many cases, the solution is simple and limited to the plaster layer. In others, a technical evaluation is essential to ensure the building remains safe and functional.

Our team provides specialized inspections, non-destructive testing and structural evaluations for all types of buildings. Contact us to receive a documented assessment and guidance on the most appropriate repair or strengthening measures.

The post Cracks in Walls: When They Are Dangerous and What to Do appeared first on Katsouris Engineering.

Many homeowners assume that solar panels are “light” or that “every roof can support them,” but in reality things are not that simple. Every roof has a different age, construction method, and load-bearing capacity. A structural assessment is therefore essential to determine whether the roof can safely support the additional weight and mechanical stresses caused by the solar panels.

Why is a structural assessment necessary before installation?

This process is not a formality. It ensures that the structure will not develop problems in the future. Solar panels add permanent weight, but more importantly, they introduce extra forces from wind, snow, and concentrated mounting points. On older buildings or tiled roofs, these loads can lead to cracking, tile displacement, or even localized failures.

For these reasons, a structural assessment has become necessary both from a technical and a safety standpoint.

What exactly does the structural assessment include?

The assessment begins with an on-site inspection. The engineer examines the type of roof (concrete slab, tiled roof, metal structure), its overall condition, and whether there are any visible issues or areas that require closer investigation.

Next, the engineer calculates the loads created by the solar system, such as:

• the weight of the panels
• the weight of the mounting structure
• wind loads (particularly important for tiled roofs)
• snow loads, where applicable

These calculations follow European standards such as EC1, EC2, EC6 and EC8 to ensure full technical documentation and compliance.

The final deliverable is the Structural Adequacy Report, an official document that includes the analysis, conclusions, and—if necessary—recommendations for small or more extensive reinforcements. With this report, the installer can proceed safely.

Is a structural check always required?

In most cases, yes. However, there are specific situations where the assessment is not just advisable — it is mandatory:

Tiled roofs

Tiled roofs are more vulnerable, especially to strong winds, and require proper mounting to avoid future problems.

Older buildings (30–40+ years old)

These buildings may have hidden weaknesses or wear not visible to the naked eye.

Lack of original plans or structural study

Very common in homes built before 1985.

Large system capacity

More panels mean higher loads.

When required by the installer or the grid operator

In many cases, the assessment is now a prerequisite.

What can happen without a structural assessment?

Solar panels are designed to operate for decades. This means the roof must remain structurally stable for decades as well.

Without an assessment, issues may arise such as:

• cracks in beams or slabs
• displacement of roof tiles
• loosening of mounting bases
• localized failures during strong winds
• insurance complications in case of damage

A small issue left unresolved at the beginning can become significantly more expensive to fix later.

What if the roof does not “pass” the assessment?

This does not automatically mean you cannot install solar panels. In most cases, required reinforcements are simple and may include:

• adding metal supports to strengthen a tiled roof
• strengthening a concrete slab with modern materials such as carbon fibers (CFRP)
• changing or improving the mounting system
• placing the panels in a different, more suitable area of the roof

The goal is always safety and long-term durability of the installation.

Cost and completion time

A structural assessment is not a lengthy process. It typically takes 2–4 days, and the cost ranges between €150–350, depending on the type of roof and the complexity of the building.

This cost includes the site inspection, calculations, photographic documentation, and the final report.

Why choose Katsouris Engineering

Our team has extensive experience in the structural analysis of all roof types and has completed numerous assessments for solar installations in both residential and commercial buildings. With every project we ensure:

• technically accurate and safe results
• close cooperation with your installer
• fast turnaround time
• clear, practical recommendations without exaggerations

Our goal is to guarantee a rooftop solar installation that operates safely and reliably for many years.

Planning to install rooftop solar panels?

We can perform the full structural assessment and guide you through every step of the process.

The post Solar Panels on Roofs: Is a Structural Assessment Required? appeared first on Katsouris Engineering.

Most owners of older houses eventually ask themselves: “Is an energy upgrade worth it?” The answer is almost always yes – and not only because subsidies are available. An energy-efficient home means lower bills, better comfort, and higher property value.

In recent years, programs such as “Exoikonomo 2025” and “Exoikonomo – Renovate for Young People” have helped thousands of homeowners significantly reduce the cost of energy improvements. Meanwhile, new initiatives expected for 2026 will further support the energy upgrade of older residential buildings.

Here’s what an energy upgrade includes and how you can benefit from available incentives.

What Does “Energy Upgrade” Mean?

An energy upgrade is a set of interventions that make a home “smarter” and more efficient in its operation. The goal is to reduce heat loss in winter and overheating in summer, so the building maintains stable comfort with lower energy consumption.

The most common interventions include:

• Thermal insulation of walls and roof

  Reduces heat loss by up to 40% and stabilizes indoor temperature.

• Replacement of old windows with energy-efficient frames

  
  Minimizes drafts, condensation, and improves sound insulation.

• Upgrade of heating/cooling systems

  
  Heat pumps, condensing boilers and inverter air-conditioning operate more efficiently with less energy.

• Installation of photovoltaic panels

  
  Allows you to generate your own electricity and drastically reduce operating costs.

• Smart thermostats & LED lighting

  
  Small interventions with immediate savings on consumption.

Once these improvements are completed, the home moves up in Energy Performance Certificate (EPC) category — a major factor that increases its market value.

Why Energy Upgrades Are Worth Considering

An energy upgrade isn’t just a technical project that ends when the work is completed. It’s a decision that pays off every single month. With proper insulation, efficient windows and modern heating systems, the home consumes less energy, which means noticeably lower bills.

At the same time, indoor comfort becomes more stable, while the property’s resale value increases — a trend that keeps strengthening in the real estate market. On top of that, you reduce the home’s environmental footprint, which many owners now consider essential.

And the best part: there are often subsidy programs that can cover a significant portion of the cost.

“Exoikonomo” Today — What Applies and What to Expect in 2026

In recent years, several cycles of the “Exoikonomo” program have been implemented, aiming to support the energy upgrade of residential buildings. The most recent cycle, Exoikonomo 2025, closed its application period on 13 April 2025 and is now in the implementation phase.

Another program, Exoikonomo – Renovate for Young People, is still active, with a completion deadline of 30 April 2026, combining energy improvements with renovation works for young homeowners.

For 2026, a new round of energy-upgrade programs is expected. However, as of today, no official guide, subsidy percentages, or application deadlines have been confirmed.

How Much Does an Energy Upgrade Cost?

The cost varies depending on the size of the house, the age of the building, and the interventions needed. Indicative price ranges:

• Wall insulation: 40–70 €/m²

• Roof insulation: 35–60 €/m²
• Window replacement: 350–900 € per opening
• Heat pump: 4,000–12,000 €
• Condensing gas boiler: 2,000–4,500 €
• Photovoltaic system 3–6 kW: 4,000–9,000 €
• Solar water heater: 900–1,800 €

Although these amounts may seem high, the real cost is significantly lower when combined with subsidies. Many households ultimately cover 50% to 90% of the total budget. Combined with the reduction in energy bills, the investment often pays back in just a few years.

Which Intervention Offers the Highest Return?

All interventions contribute to energy efficiency — but not equally. Based on experience with older homes, the ranking is:

1. Exterior insulation

The most effective measure. Reduces heat losses in winter and heat gains in summer. Rating (5/5): ⭐⭐⭐⭐⭐

2. Window replacement

Provides major thermal improvement and better comfort, especially in homes with single glazing. Rating (4/5): ⭐⭐⭐⭐

3. Heat pump

Particularly cost-effective in homes with long operating hours. Reduces heating costs by up to 50%. Rating (4/5): ⭐⭐⭐⭐

4. Solar water heater

Low installation cost and immediate results. Rating (5/5): ⭐⭐⭐⭐⭐

5. Photovoltaics

Ideal for homes with high electricity consumption and direct impact on energy dependency. Rating (3/5): ⭐⭐⭐

For homes aged 20–40 years, the best cost-to-benefit combination is usually:
insulation + windows + solar water heater.
With subsidy support, this package is often the most affordable and balanced solution.

Energy Upgrade vs. Regular Renovation — What’s the Difference?

Many owners confuse general renovation with energy upgrading. But the two concepts have different goals and outcomes.

What is a “regular renovation”?

A typical renovation involves flooring, bathroom/kitchen upgrades, painting or aesthetic improvements. It enhances the look and functionality of the space but doesn’t necessarily reduce energy consumption.

What is an energy upgrade?

It focuses on systems, materials and techniques that reduce operating costs and improve thermal comfort. It is an investment that pays off through lower bills, higher property value, and better quality of living.

Which one should you choose?

For most homeowners, the ideal approach is a combination:
start with the energy upgrade (which has technical benefits and long-term savings), then proceed with the aesthetic renovation.
This avoids repeated work and results in a modern, comfortable and cost-efficient home.

The post How to Improve the Energy Performance of an Older Home appeared first on Katsouris Engineering.

Over time, factors such as weather, moisture, and seismic activity affect every structure’s performance. That doesn’t mean every inspection requires drilling, sampling, or breaking materials. Today, technology allows engineers to “see inside” concrete, detect cracks, moisture or corrosion, and accurately evaluate the strength of the structural frame.

What is a Non-Destructive Inspection?

It is a set of measurements and tests performed directly on the load-bearing elements of a structure (columns, beams, slabs), without removing or damaging any part of the material.

These measurements are taken with special electronic instruments that can “read” inside the concrete, identify reinforcement bars, and detect changes in density, moisture, or material strength.

The goal is to identify early:

• hidden cracks or voids,
• corrosion of steel reinforcement,
• areas with excessive moisture or reduced strength.

The results provide an objective picture of the building’s condition and can be used either to design strengthening measures or to confirm that the structure remains safe.

When is a Non-Destructive Inspection Needed?

NDI is applied in many situations, such as:

• older or undocumented buildings,
• visible cracks, stains, or signs of wear,
• before renovation or change of use,
• prior to a structural adequacy or retrofit study,
• or after an earthquake or fire, to verify structural safety.

This process is not only technical – it’s preventive. Just like a medical check-up shows a person’s health, a non-destructive inspection reveals the “health” of a building.

The Main Modern Methods Used Today

1️⃣ Geometric Survey of the Structural Frame

Using electronic distance meters or 3D laser scanning, the exact dimensions of structural elements are recorded.
This allows the creation of a digital (BIM) model, helping engineers identify deviations and perform a precise structural analysis.

2️⃣ Rebar Detection

With devices such as the HILTI PS300, steel reinforcement bars within concrete are located and their cover thickness measured.
This reveals whether the reinforcement is properly protected or if there are signs of corrosion requiring intervention.

3️⃣ Surface Hardness Testing of Concrete

Using a Concrete Test Hammer (HT-225), the surface hardness of concrete is evaluated.
It provides valuable information about the quality and uniformity of materials, without the need for core sampling.

4️⃣ Moisture Measurement

Moisture is one of concrete’s main enemies.
Special sensors detect areas where water has penetrated — a sign of potential rebar corrosion or surface delamination.

What the Results Show

The collected data from all tests are analyzed together to build a clear picture of the building’s structural condition.
Depending on the findings:

• High moisture may suggest waterproofing or crack repair.
• Low strength may lead to further sampling for confirmation.
• If everything is within limits, the results act as proof of structural integrity.

Non-destructive inspections are not only diagnostic — they form the foundation of every structural adequacy assessment or maintenance plan.

Why It Matters to Building Owners

A non-destructive inspection is a preventive investment that can prevent serious issues later on.
It helps property owners:

• Understand the true condition of their building.
• Prevent costly structural damage.
• Obtain technical documentation for permits, insurance, or property transfer.
• And most importantly – gain peace of mind about the building’s safety.

If you want to learn more about our non-destructive building inspections and the modern techniques we use,
visit the dedicated page:
👉 Non / Semi-Destructive Building Inspections »

If you are planning a Structural Adequacy Study, you can also read:
👉 Structural Adequacy Assessment – When It’s Required and How It’s Done »

The post How Non-Destructive Building Inspections Are Done with Modern Tools appeared first on Katsouris Engineering.

If you own a tourist accommodation, educational facility, hospital, fuel station, or any building open to the public, obtaining the certificate is now mandatory.
For all other properties, the Building Identity Certificate is required for every sale, donation, inheritance, or legalization of unauthorized constructions.

In the following guide, you will learn who is required to obtain it, which documents are needed, and how to complete the process properly and without delays.

What Is the Building Identity Certificate

The Building Identity Certificate is the digital record of each property, confirming its legal status. Through the official TEE (Technical Chamber of Greece) platform (web.tee.gr):

• Building permit and architectural drawings
• Energy Performance Certificate (EPC)
• Declarations of building legalization
• Structural adequacy study or technical report
• Floor-area distribution tables and other legal documentation

The process is carried out exclusively by a licensed engineer, who submits the data and issues the Certificate of Building Completeness.

Who Is Obliged to Obtain It

Since February 1, 2021, the Building Identity Certificate has been mandatory for all private and public buildings (Ministry of Environment and Energy). However, the following categories must obtain it by January 31, 2026:

• Tourist accommodations over 300 m²
• Schools and childcare facilities
• Hospitals and healthcare centers
• Public-assembly buildings (theaters, cinemas, gyms, etc.)
• Fuel stations, car washes, and repair workshops
• Public buildings and municipal facilities

For all other buildings (residences, apartments, offices, etc.), the certificate is required whenever

• there is a sale, donation
• legalization of irregularities
• issuance of a new building permit

Deadline and Processing Time

The deadline for special building categories is January 31, 2026, as stated by the Ministry of Environment and Energy.

The time required depends on the completeness of each file. If all documents are available, the certificate can be issued within a few days. If new surveys or records from local authorities are needed, it may take a few weeks.

View the official Ministerial Decision on the Building Identity Certificate (Government Gazette B’ 334/29.01.2021)

Fines for Delay or Non-Issuance

Failure to issue the Building Identity Certificate on time results in penalties imposed by the Special Secretariat for Environmental Inspection:

• Minimum fine: €200
• Maximum fine: Up to 10 % of the property’s objective value

The fines remain valid until the certificate is properly issued.

Documents Required by the Engineer

To proceed, your engineer will need:

1. The original building permit with all revisions
2. Updated architectural drawings and plans
3. The Energy Performance Certificate (EPC)
4. Structural adequacy study or technical report (if required)
5. Legalization declarations for any unauthorized works
6. Ownership allocation tables (for multi-unit buildings)

If some documents are missing, the engineer can issue a certificate of loss and create new digital drawings.

Why You Should Act Now

The Building Identity Certificate is more than an obligation – it is the official assurance that your property is fully legal, safe, and ready for any transaction.

Completing the process in time means you:

• avoid future fines and delays,
• are always prepared for property transfer or renovation,
• and strengthen the value and credibility of your property.

At Katsouris Engineering, we handle the entire process for you – quickly, accurately, and transparently.

Our team takes care of:

• Legal and technical compliance checks
• Collection and digital upload of all documents
• Structural adequacy inspection (if required)
• Submission to the TEE platform and issuance of the final completeness certificate

This ensures your property is fully compliant and ready for any use or transaction.

📧 Contact us for a free file pre-check and an indicative offer.

Frequently Asked Questions

The post Building Identity Certificate 2026 – Who Risks Fines appeared first on Katsouris Engineering.

Project Details

• Location: Ilion, Attica
• Building Type: New three-story apartment building with pilotis and basement
• Team Role: Architectural, structural, and MEP design, permitting, and supervision
• Key Features: Energy Class A, modern architecture, and highly functional living spaces

Scope of Works

• Architectural Design: Facade and interior design emphasizing geometric balance, natural light, and elegant simplicity.
• Structural Design: Reinforced concrete structure based on EC2/EC8 standards, including seismic analysis and optimized foundation.
• MEP Installations: Energy-efficient lighting, building automation, insulation, and HVAC systems for reduced energy demand.
• Energy Performance: High-performance glazing, thermal façade insulation, and photovoltaic-ready infrastructure (PV-ready).

Result

A modern residential building combining aesthetics and functionality, designed to meet the needs of contemporary urban living.
The project ensures low energy consumption, comfort, and long-term structural durability.

Looking to design your next residential project?
We deliver comprehensive architectural, structural, and MEP engineering services — from design and permitting to construction supervision — with a focus on safety, efficiency, and modern aesthetics.

The post New Three-Story Apartment Building with Pilotis and Basement in Ilion appeared first on Katsouris Engineering.

Project Details

• Location: Corfu International Airport (CFU)
• Scope: Construction of new fuel storage tanks and fuel transfer infrastructure
• Team Role: Concept design, structural and MEP engineering, permitting, supervision

Scope of Works

• Earthworks & Concrete: Excavations, foundations, reinforced concrete bases, and drainage systems.
• Tanks & Piping Networks: Installation of aboveground tanks, suction and return pipelines, ventilation systems, and safety valves.
• Environmental Protection: Fuel containment bunds, impermeable surfaces, stormwater management, and oil-water separators.
• Electrical & Automation Systems: Grounding, lightning protection, area lighting, level and overfill sensors, local and remote monitoring.
• Fire Safety & Security: Firefighting network, ATEX compliance signage, alarm systems, and spill response plan.

Regulatory Compliance

The project design follows international standards and best practices, including:

• ICAO Annex 14 – Aerodrome Design and Operations
• EASA ADR Regulations
• ATEX / EN 60079 for explosive atmospheres
• NFPA 30 / API 650 for fuel storage tanks
  Fully aligned with the HCAA requirements, emphasizing safety, resilience, and system traceability.

Quality Control & Testing

• Hydrostatic and leak-tightness tests.
• Grounding and lightning protection checks, as well as automation system validation.
• Frequent on-site inspections and detailed as-built documentation.

Result

A comprehensive and safe fuel storage installation, designed for:

• operational efficiency,
• easy maintenance,
• full regulatory compliance, and
• reduced environmental impact.

Need expert design or supervision for fuel storage or industrial facilities?
We deliver complete engineering, permitting, and supervision services, focusing on safety, reliability, and sustainability.

The post Construction of New Fuel Storage Tanks at Corfu International Airport (CFU) appeared first on Katsouris Engineering.