Waterproofing with membranes: efficiency, durability and innovation, the growing solution for roofs

 

Waterproofing is one of the fundamental pillars of any construction project. The lack of an effective system can lead to leaks, structural damage, mold growth, energy inefficiency, and high maintenance costs. Weather conditions, UV exposure, temperature fluctuations, and water accumulation on roofs demand materials and techniques that ensure watertightness for decades.

 

Currently, there are essentially two main approaches in this field: liquid systems and waterproofing membranes. In this article, we explain the differences, advantages, and challenges of each system, how the market is evolving, and Prudêncio’s perspective on the most innovative solutions, with a special focus on TPO membranes.

 

 

Liquid systems vs. membranes: what sets these solutions apart?

 

Liquid systems are coatings applied directly to the surface (using rollers, brushes, or spraying), forming a continuous waterproof film that adapts to the shape of the surface. The most common ones include:

 

• Polyurethane: known for its elasticity and resistance to thermal variation. Recommended for roofs with high structural movement.
• Acrylic: a more economical option, but less durable under extreme weather conditions and with limited resistance to standing water.

 

Although popular for their ease of application and ability to cover complex geometries, liquid systems face challenges in achieving uniform layer thickness and require ideal weather conditions during application and curing.

 

 

Membranes, on the other hand, are prefabricated sheets with uniform thickness, typically made from modified bitumen, synthetic rubber, or thermoplastics. They are applied in double layers (bituminous) or single layers (EPDM and thermoplastic membranes) and sealed using heat (torch flame for bituminous, hot air for thermoplastics) or specific adhesives (EPDM membranes). The most common types include:

 

• EPDM (Ethylene Propylene Diene Monomer): a synthetic rubber membrane used in flat or low-slope roofs. Known for excellent resistance to temperature variations and UV rays, low maintenance, long lifespan, and recyclability. However, seams are glued, which can be a weak point.
• PVC (Polyvinyl Chloride): a thermoplastic membrane used on flat or low-slope roofs. Flexible, adaptable, and easy to weld, but contains plasticizers that are harmful to health and the environment. Over time, these plasticizers leach out, especially with standing water, contaminating the surroundings. This also causes compatibility issues with substrates like bitumen, EPS, and polyurethane.
• Bituminous Membranes: made from fossil fuel-derived bitumen, used on flat or low-slope roofs. When modified with certain polymers (SBS or APP), they become more flexible and resistant to thermal cycles. Double-layer application adds safety but also increases weight. The use of torches poses fire and burn risks, results in less ergonomic working conditions (due to gas cylinders), and messy applications involving melted bitumen.
• TPO (Thermoplastic Polyolefin): like other thermoplastics, TPO membranes are used on flat or low-slope roofs. They stand out for enhancing energy efficiency (by reflecting UV rays and reducing cooling/heating demands), being eco-friendly (no toxic compounds or plasticizers, fully recyclable, and highly resistant to chemicals), and for their durable seams. KÖSTER is one of the world’s oldest TPO manufacturers and part of an elite group producing PE-based TPOs. Their membranes feature an innovative aspect: both upper and lower layers are made of the same high-quality material.

 

 

Because membranes are produced under controlled industrial conditions, they maintain consistent physical and mechanical properties, regardless of who installs them. EPDM and TPO particularly contribute to sustainability. Their homogeneous composition ensures uniform strength and greater quality control.

 

These features make membranes especially suitable for large, flat roofs and technically demanding areas, where long-term performance is critical.

 

 

Technical advantages of waterproofing membranes

 

While liquid systems offer versatility and ease of application, membranes provide strong assurance of waterproofing success:

 

• Superior durability, often exceeding 20 years.
• Reduced human error, since the membrane’s controlled thickness and quality are not reliant on the applicator’s skill.
• Immediate usability of the waterproofed area, as membranes don’t require curing like liquid systems.
• Greater quality control, thanks to membrane uniformity. With liquid systems, it’s hard to assess thickness and adhesion during or after application.
• Higher mechanical resistance, due to embedded reinforcements, providing better tensile strength and puncture resistance — unlike liquids, which are prone to blistering and poor adhesion.
• Energy efficiency, especially with TPO membranes that reflect sunlight and reduce interior temperatures and HVAC costs.
• Eco-friendliness, as many membranes (like EPDM and TPO) are recyclable and have low environmental impact during manufacturing.
• Reliable detailing, since membranes better handle complex joints and critical zones. Accessories are available to ensure proper treatment of details — key to successful waterproofing.

 

 

 

Primary applications

 

Membranes are widely used on flat and sloped roofs of commercial, industrial, and residential buildings. They are ideal for refurbishing old roofs that require full waterproofing replacement or fixing problematic ones, such as those made of fiber cement or metal.

 

They are also suitable for structures exposed to high solar radiation and aggressive weather. Additionally, membranes play a vital role in green roofs, like terraces and gardens, where watertightness and mechanical strength are essential.

 

 

Trends and innovation in the sector

The global waterproofing market is clearly expanding, driven by the demand for longer-lasting solutions, energy efficiency, and sustainability. According to recent studies, TPO membranes are growing above the market average, becoming a preferred option for industrial and commercial roofing.

 

Flat and slightly sloped roofs are the main users of such systems, due to their exposure and the need for flawless waterproofing. In flat roofs, the waterproofing system is solely responsible for water tightness, demanding extra care in system selection.

 

Leading companies like KÖSTER are gaining prominence for their innovation in developing high-quality TPO membranes, becoming global references in the field.

 

 

 

Prudêncio’s vision: commitment to technical excellence

The evolving waterproofing sector demands a proactive approach. At Prudêncio, we respond with innovation, continuous training, and proven solutions, such as the use of KÖSTER’s TPO membranes, rooted in field experience and a focus on quality.

 

We know that details make all the difference. That’s why we invest in specialized teams, rigorous application methods, and solutions that ensure longevity, reliability, and sustainability.

 

Waterproofing is a science. And at Prudêncio, we treat it with the rigor it deserves.