The transparent roof solution from Copenhagen to the world

October 10, 2023
Olga Kizina

The transparent roof, especially the transparent material, is a bit like something from science fiction or the Harry Potter movies," says the head of the Nebesys start-up, Přemysl Kokeš.

"At first glance, it appears to be a classic ceramic red roof, fitting seamlessly into the historic center of the city. However, beneath it lies an illuminated attic space, protected by a transparent surface made of glass and aluminum. Residents and visitors alike can enjoy a panoramic view of the surroundings, thanks to the environmentally friendly Nebesys roof system from the Czech start-up The system has recently advanced to the final round of the Vodafone Idea of the Year competition, which featured the participation of 129 innovative companies this year.

“I got the idea for such a roof back in2011 when the owner of a house in Litomyšl approached me to propose a new roof for his historic building. I decided to enhance the attic and introduce natural light from the sky under the roof. Consequently, the very first Nebesys roof was created for 1.5 million CZK. Everyone was satisfied—the owner, preservationists, and myself," architect, founder, and 60% owner of the start-up Přemysl Kokeš told Creative Business Network.

Magic light

It did not come into being immediately after the first project. 'For eight years, I waited to see if the heat and cold would leave their mark on the roof. Storms, wind, and snow came, and nothing happened; everything worked as it should. So, three years ago, I roofed our family hotel in Mikulov similarly,' added Kokeš. He founded the start-up shortly afterward, at the beginning of last year. To date, he has completed three projects and has dozens of orders in the design stage. For this year, he expects sales of over 20 million CZK.

The original solution involves placing triple glazing on an aluminum frame, which can adapt to the various unevenness of old roofs, serving as a thermal and waterproofing layer. It doesn't cover the entire roof, as that would be unnecessarily expensive. Typically, it is installed on half of the roof deck surface, while the other part remains non-transparent with the above-rafter thermo-insulation, made of sheet metal or PVC. The entire structure is then covered with metal roof tiles featuring hundreds of small holes, either from specially treated aluminum or copper. These tiles allow in less than a third of solar radiation, created by scattered rays from the sky, not direct sunlight, perfectly shaded by the perforated rooftiles.

“The roof tiles allow in less than a third of the sun's radiation. Our goal is to harness diffused rays rather than direct sunlight, ensuring that the space under the roof does not overheat”

There is enough pleasant light under the roof without the attic getting overheated. According to one of the company's tests, the temperature rose to 58 degrees Celsius on a hot day under a classic roof with a skylight, whereas it stabilized at 27 degrees Celsius under the Nebesys roof. This is all thanks to its design - a 'naturally ventilated roof façade with smart shading.'

The Nebesys system also cools itself through a network of tubes in the battens near the glass plates, which release rainwater from the reservoir. On a hot day, rainwater is pumped from the tanks onto the roof and evaporates, lowering the surface temperature. "The roof is similar to the leaves of trees; they also let in only part of the light and cool the surroundings by evaporation," explains the architect.

Additionally, the windows do not need frequent washing because the water washes away dirt, including dust. Due to the nanotechnological treatment of the surface of the upper glass, dust turns into balls that can be easily removed. So, similar to tree leaves, the roof also reduces dust in cities.

It is also possible to completely darken the attic with a blind. This prevents the rooms from being visible from a height and a certain angle in the evening, especially after the lights are on.

There is light in the space below it even in winter when it is covered by a ten-centimeter snow layer. The roof can even withstand the weight of a 1.5-meter-thick layer of snow.

Another advantage is the protection of the agricultural landscape from real estate development. Giving a second chance to unused attics decreases the demand to develop new houses in the suburbs. This approach is highly environmentally friendly and makes economic use of the existing technical infrastructure in the city.

Currently, the company is developing a way to ensure that roofs are energy self-sufficient and that photovoltaics can be easily integrated into them. 'It's a great idea, and a Czech one. You can see outside, there is the required lighting under the roof, and the thermal insulation is also excellent. Preservationists appreciate that, where glass is not visible under the perforated bags, cooling devices, or heat pumps can be hidden,' says Pavel Svoboda from the Department of Construction Technology at Technological University in Prague, evaluating the Nebesys system.

From Copenhagen to the World

The start-up has planned expenses of 66million CZK for the launch. For the most part, they have already secured funding from investors, including the boss. Currently, it has twelve employees: traders, developers, and individuals for assembly and production, concentrated in Lanškroun. There are warehouses in Hlinsko and a showroom in Prague Chrášťany.

So far, the customers are from the Czech Republic. Sometimes they are attracted by the start-up itself, and other times they get connected through the architects they work with. Not only do people come from city centers needing to innovate a classic roof according to the requirements of preservationists, but there are also more and more people who do not yet have a pitched roof with roof tiles and are just about to buy one.

"The Czech Republic was intended to be a pilot market for us before expanding further into Europe and overseas. However, we have had to adjust our plans a little because we are already being contacted by property owners from abroad. A few orders from Germany are already being handled, and more are coming from southern countries such as Portugal, Spain, or Greece. For instance, a hotel in Thessaloniki has reached out to us. In these regions, there is also interest in roofs without insulating facades underneath because it is possible to have a lawn, a garden, or a BBQ place under the aluminum tiles, allowing rain and air to flow through," Kokeš points out.

Abroad, people learned about the Czech company thanks to the fact that this year in Copenhagen it won the Creative Business Cup 2023 Global Finals, the competition for the most creative start-up of the year. "Standing in front of a jury evaluating not only the creativity of the product but above all its business potential was difficult. But Nebesys deservedly won," points out Alena Hájková from the Czechinvest agency.

So far, the company is capitalizing on the fact that no one else offers anything similar in the Czech Republic, Europe, or even globally. Those within the industry also describe the idea as surprising.

"We stayed in the Mikulov hotel in the attic, and when we went out on the street the next morning and looked at the roof, my wife asked where the window in the room was. None could be seen from below. I went back to find out, and it turns out I work at Nebesys. I also put my savings into it," shared Jaroslav Nesiba, a builder with experience in a multinational company, who has since become a sales director.

The company is currently protecting itself with patents. "I want it to be a successful global project that can help change the world. I know it sounds lofty, but it's true," emphasizes Kokeš. According to him, there are more ways to achieve this, and he does not rule out selling the company to someone who has the appropriate capital. However, a connection with a strong partner that would help reach foreign markets, with the right distribution channels, is more likely, closing the interview with Business Development Manager, Radim Senk.

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