What Is Waterproofing and Why Your Building Needs It

Waterproofing is the protection of a building against the penetration of water and moisture into its structural elements. In practice, it is the application of specialised materials and systems that create a watertight barrier between the water and the structure. Without reliable waterproofing, water penetrates the concrete, corrodes the reinforcement, causes cracks and leads to problems that get worse over time.

Damp-Proofing and Waterproofing: Are They the Same Thing?

Yes. In the Greek market the two terms are used interchangeably and refer to the same process. Damp-proofing or waterproofing describes the protection of building surfaces against water penetration, by applying suitable membranes, coatings or liquid waterproofing materials.

The term you come across usually depends on the professional or company using it, not on any difference in the process.

Where Does a Building Need Waterproofing?

Waterproofing is not only about the roof. Every surface that comes into contact with water or moisture needs protection:

• Roof: The most exposed part of the building. It takes rain, snow, UV radiation and temperature swings that reach 50-70°C
• Balconies and terraces: Horizontal surfaces that collect water and require a watertight base beneath the tiles
• External walls: They absorb moisture from rain and snow, especially when there are cracks in the render
• Basements and foundations: They are in direct contact with moisture from the ground
• Bathrooms and kitchens: Spaces with constant production of water vapour that require local waterproofing

Why Is Roof Waterproofing Essential?

The roof is the most exposed structural element of the building. It is stressed every day by rain, frost, intense sunlight and sudden temperature changes. Without reliable waterproofing, water finds its way through even the smallest cracks and joints.

The consequences are not only cosmetic:

• Leaks inside and damp on the walls
• Corrosion of the concrete reinforcement
• Mould growth that affects the occupants' health
• Cracks from expansion and contraction due to temperature changes
• Serious structural damage whose repair cost far exceeds the cost of prevention

The cost of not waterproofing is always many times higher than the cost of proper waterproofing.

What Are the Roof Waterproofing Methods?

There is no single solution that suits every roof. Choosing the right method depends on the condition of the surface, the type of building, how the roof is used and the budget.

Waterproofing with Bitumen Membranes

The most proven and widespread method. SBS bitumen membranes are torch-applied hot and create a continuous, watertight surface.

Suitable for:

• New buildings
• Replacing old membranes
• Roofs without active cracking problems

Advantages:

• Excellent durability over time
• Perfect adhesion to all building materials
• Follows the contraction and expansion of the surface
• Can be applied in all seasons

Learn more about Waterproofing with Bitumen Membranes →

Waterproofing with Hyperdesmo

A polyurethane, elastic membrane that is applied in liquid form and creates a single watertight surface with no joints or seams.

Suitable for:

• Roofs with cracks and recurring leaks
• Surfaces under heavy UV stress
• Cases where high elasticity is required

Advantages:

• Complete watertightness with no weak points
• High adhesion to concrete
• Heat-reflective white colour
• Resistance to UV radiation and thermal stress

Learn more about Waterproofing with Hyperdesmo →

Waterproofing with Mapelastic for Tiled Surfaces

A two-component, elastic cementitious mortar with excellent waterproofing properties. Ideal for surfaces that will be covered with tiles.

Suitable for:

• Terraces and balconies
• Walkable tiled roofs
• Surfaces with cracks wider than 2mm

Advantages:

• Long-lasting waterproofing beneath tiles
• Fully walkable with an attractive finish
• Vapour permeability
• Excellent adhesion to cement mortar

Waterproofing or Thermal Insulation: What Do I Need?

This is the question we are asked most often. The answer depends on the problem you are facing, but in most cases you need both.

You need waterproofing when:

• There are leaks or damp inside
• The roof shows cracks or wear in the existing membrane
• You want to protect a new building from the start

You need thermal insulation when:

• The house gets cold quickly in winter or overheats in summer
• Electricity bills are disproportionately high
• Mould appears in the corners and on the ceiling because of thermal bridges

Combining the two is the best solution because the roof is responsible for 55-65% of a building's heat losses. Waterproofing without thermal insulation protects against water but leaves the energy problem unsolved. Thermal insulation without waterproofing leaves the insulation at risk from leaks.

Read the Complete Roof Insulation Selection Guide →

When Do You Need Waterproofing: The Signs You Should Not Ignore

Many owners discover that they need waterproofing only after the problem has already spread. These are the signs that call for immediate action:

• Damp patches or discolouration on the ceiling after rain
• Peeling or blistering of the existing roof membrane
• Visible cracks in the render of the external surface
• Damp on the walls near the ceiling
• Mould on the ceiling of the top floor
• Standing water on the roof after rain due to inadequate falls

The sooner the problem is dealt with, the lower the cost of the work.

How Roof Waterproofing Is Done: The Application Stages

Properly applied waterproofing follows specific stages that cannot be skipped:

1. Technical inspection Checking the condition of the roof, measuring the moisture of the substrate and assessing drainage. Application on a substrate with moisture above 4% almost always leads to system failure.
2. Surface preparation Cleaning, removing loose material, repairing cracks and levelling out irregularities. Proper preparation is the foundation of a successful application.
3. Creating falls Applying foam concrete to create slopes of 1.2-1.5% towards the drains. Without adequate falls, water ponds and puts strain on the waterproofing.
4. Applying the waterproofing Laying the chosen membrane or material with the correct technique, paying particular attention to sensitive points such as drains, parapets and penetrations.
5. Final check Inspection, watertightness test and handover with a written guarantee.

How Long Does Waterproofing Last?

Its lifespan depends on the method and the quality of application:

• SBS bitumen membranes: 22-25 years with proper maintenance
• Hyperdesmo: 10+ years with maintenance every 5 years
• Mapelastic with tiles: 20+ years

The three factors that determine how long it lasts are proper surface preparation, professional application with certified materials and regular maintenance.

See detailed Roof Insulation Prices →

Request a Technical Assessment

Waterproofing is not a job that gets repeated often. When it is done right the first time, it protects your building for decades.

Goumas Insulation, with 25+ years of specialised experience, certified crews and a written guarantee for every project, provides you with:

• An on-site technical assessment
• An accurate diagnosis of your roof's condition
• A solution tailored to the real needs of your building
• Certified materials with a written application guarantee
• Respect for the schedule and the budget
• Support after the project is completed

Request a Quote →

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Phone: 210 244 0600

Frequently Asked Questions about Waterproofing

What is roof waterproofing?

It is the application of specialised materials to the surface of the roof that create a watertight barrier and prevent water from penetrating the structural elements of the building.

How often is waterproofing needed?

It depends on the system and the quality of application. Bitumen membranes last 25-30 years, while systems such as Hyperdesmo need maintenance every 5 years.

Can an old roof be waterproofed?

Yes. On roofs where the existing membrane is in good condition, a new layer can be applied without complete removal. Where there is serious damage, complete removal and a new application are required.

Do I need waterproofing and thermal insulation together?

In most cases, yes. Combining them offers complete protection against damp and energy losses, energy savings of up to 65% and the maximum lifespan for the structure.

When is the best time of year for waterproofing?

Spring and summer are the ideal periods. The basic requirements are no rainfall, a temperature above 5°C and substrate moisture below 4%. In winter, application is possible in dry weather with a moisture measurement.

Is investing in waterproofing worth it?

Absolutely. You avoid thousands of euros in future repair costs from leaks, protect the load-bearing structure from corrosion and preserve the value of your property.