The importance of KÖSTER

Environmental responsibility, sustainability and technical superiority are at the same time the principle and result of the partnership between Prudêncio and the German brand KÖSTER.


Prudêncio is proud to have the exclusive representation in Portugal for TPO of KÖSTER.




KÖSTER is one of the oldest TPO manufacturers in the world. It belongs to a restricted group of PE-based (polyethylene) TPO producers, to which it added a distinctive feature: the top and bottom layers are produced using the same quality material.


To better understand the importance of this brand in the waterproofing sector, you can read below the interview with Hugo Torres, International Sales Manager of KÖSTER: 


What is the origin of the KÖSTER brand?

Hugo Torres: KÖSTER was founded in 1982 in Aurich in Germany. Aurich is a town in northern Germany, about 30 minutes from the North Sea coast and another 30 minutes from the Dutch border. Being a fertile region in water and with characteristics very similar to the Netherlands, with many canals, dams and in which part of the territory is below sea level, there has always been a great need for waterproofing of houses, especially negative side, segment in which it became the world’s greatest specialist.


Also because it is an area where it rains a lot, almost all year round, the waterproofing theme is of vital importance, having developed very rapidly as a specialist in this market niche within the civil construction sector, developing and producing more than 200 solutions different for this market segment.


What are the brand values?

H.T.: Fundamentally, much respect for the environment and unrivaled quality in all the products and systems it develops and produces.


Why would you say that TPO membranes are the best option in most waterproofing works?

H.T.:Because it is undoubtedly the latest and most evolved, most durable, most versatile and environmentally friendly technology that can be used in waterproofing in 2019.


Rehabilitation 9Zero9 Condominium Administration – Waterproofing TPO – Prudêncio’s Work



What distinguishes KÖSTER TPO membranes from other TPO membranes on the market?

H.T.: Firstly, the fact that we use a polyethylene polymer, when most (only 2 other German manufacturers also use PE) uses polypropylene. This offers real advantages for product quality, such as higher chemical resistance (pollution, acid rain, etc.), better behavior in contact with UV rays, which reduces its impact and increases durability with less degradation, better behavior mechanical, fruit of higher density of PE in relation to PP. Also resistance to low (negative) temperatures is an objective value.


There is a misconception that materials suffer most at high temperatures, particularly from “hot” countries, when it is precisely the opposite. Any material has a medium strength at high temperatures between 110 ° C and 140 ° C, so there is no great variation. When we move to negative temperatures, most materials “struggle” with temperatures below 5 ° C, most of which are limited to -10 or -15 ° C. When temperatures are reached at -10 ° C sustained for 1 or 2 weeks in winter, materials can transition into glass, which means they start to behave like glass without any elasticity. This is dramatic for a waterproofing membrane, which breaks easily. Our TPO, because it is PE, has a glass transition close to negative 100ºC, and maintains its elasticity without changes until this temperature. Our product has a flexible certification at <- 50ºC.


Pingo Doce Évora – Rehabilitation of Metal Roof – Prudêncio’s Work



What are the advantages of KÖSTER TPO membranes?

H.T.: In addition to what I have already mentioned, another important point is that we use the same mixing quality in the upper and lower layers of the membrane. The other manufacturers use a higher quality top layer (because it is exposed) and a lower layer in which they extract many additives from the recipe, such as stabilizers and UV protectors, pigment, chemical stabilizers, among others, just for the purpose of lowering costs of production. KÖSTER does not do this for the simple reason that by having the same quality of recipe in the top and bottom layer, it will give you the best bonding ability in the overlap of the screens when they are heat-welded. This is because we are heat-welding exactly the same material.


This year, at the Munich fair (BAU), we wanted to demonstrate that we have the strongest union in the overlaps. We made live unions and submitted these joints in a machine that measures the force of the separation of the heat-welded joint and registers the value. We have never obtained values ​​below 500 N / mm2, while our competitors never reach more than half of that value, 250 to 270 N / mm2.


Basic School of Padre Cruz District – DGESTE – Prudêncio’s Work



Are Koster’s TPO membranes only applied to roofs? What are the applications of these membranes?

H.T.: No. TPO membranes are waterproofing membranes, so they can be used in any field of application that requires waterproofing. This includes buried structures such as retaining walls or earthen slabs, terraces and balconies, flower gardens and gardens, water tanks and water treatment plants, intermediate floors, among many others.


Pingo Doce Aveiro – Rehabilitation of Metal Roof – Prudêncio’s Work


What is the importance of the certifications attributed to these membranes, namely “FLL certification for green roofs” and “Certification for drinking water”?

H.T.: External certifications are fundamentally ways to ensure that materials meet certain requirements, such as the cases they mention, although there is still a long way to go in harmonizing standards and certifications, especially from country to country. I am referring especially to the countries within the European community, but also in other parts of the world.


Then, as in many other industries, it is also a highly profitable business for government organizations and entities.


Why did you choose Prudencio as an exclusive representative in Portugal?

H.T.: We chose Prudêncio because we share the same values of exigency in the quality of the service provided, in the transparency and honesty in the businesses and in the correction in the exercise of our activity. We as manufacturers and Prudêncio as an applicator. We are very grateful for this partnership.


Application by Prudêncio


Consult here a work of Prudêncio using KÖSTER TPO membranes.


SEE ALSO: KOSTER Waterproofing TPO Membranes


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