Clarion Hotel Helsinki

© FI/Helsinki, Hotel Clarion,

Thrills on the 17th floor

In the Clarion Hotel in Helsinki, the pool protrudes 1.5 meters out of the building – 17 floors up. Whoever dares to look down when swimming over the transparent floor made of PLEXIGLAS® should have a good head for heights.

Helsinki is located on the coast of the Gulf of Finland. The Clarion Hotel offers the unique view over the old harbor of Jätkäsaari, where numerous ships arrive every day. Not only is the view from the hotel extraordinary, but its stainless steel pool, protruding from the building like a balcony, is also a spectacular sight.

A pool for those with a head for heights

Describing her experience, a hotel guest from England said: “My heart nearly stopped.” Another guest didn’t even dare to swim to the end of the pool. This is exactly the type of thrill that the architect of the Clarion Hotel wanted to create for the future guests. Gerold Wimmer from Berndorf Metall- und Bäderbau GmbH supported him in this endeavor. “Together we thought about how to design and plan a stainless steel pool at a lofty height on the 17th floor,” says the Austrian, who is responsible for the Scandinavian market as Sales and Business Development Manager. This was how he came to face his biggest challenge to date: The pool is a balcony with a transparent floor – with a clear view ahead and down to the ground 50 meters below. “Guests better have a good head for heights,” laughs Wimmer.

The right combination of expertise and appropriate materials is key to building a structure that has to hold a volume of 54 cubic meters of water on the 17th floor. “We have been building stainless steel pools since 1960,” says Wimmer proudly. The material has the advantage of being particularly durable, neutral and easy to maintain. For the Clarion Hotel, the Berndorf Metall- und Bäderbau GmbH produced a stainless steel structure with a width of four meters and a length of ten meters. Moritz Meinesz and his company Hydrosight were brought in to add that special something, the transparent floor which protrudes 1.5 meters out of the building.

Permanent transparency

Thanks to PLEXIGLAS®, the view from the stainless steel pool is always spectacular. Despite the elements, Röhm’s brand acrylic glass does not turn yellow and retains its high level of transparency. Read more on Röhm’s 30-year guarantee on PLEXIGLAS®

An undistorted view

The company from Emmerich am Rhein specializes in underwater windows made of PLEXIGLAS®, Röhm’s brand acrylic glass. “Customers are always asking why we don’t use glass,” says Meinesz. Glass would have to be very thick to withstand the water pressure and would have a greenish tint. This is why glass is not really suitable for this type of application. “With PLEXIGLAS®, however, we are able to produce windows which let all the light through, showing everything in its true color and offering excellent transparency while still being extremely strong,” says the expert. Gerold Wimmer is also convinced by the properties of the acrylic glass, “since it is really easy to combine stainless steel with PLEXIGLAS®.”

A heavyweight pool

“The properties of PLEXIGLAS® speak for themselves. It is lighter than glass, can withstand a lot and does not turn yellow.”

Gerold Wimmer
Sales and Business Development Manager, Berndorf Metall- und Bäderbau GmbH

The floor and one of the sides of the L-shaped pool are each made of a large, transparent block of PLEXIGLAS®. The 3.5 meter by 1 meter and 3.5 meter by 1.1 meter large panels were placed into the stainless steel pool on site in Helsinki. This was a logistical challenge, since the two blocks of PLEXIGLAS® weigh one ton and the bay together with the steel frame weighs 1.7 tons. Therefore, Meinesz arranged for the structure to be delivered during the construction phase of the Clarion Hotel in Helsinki in order to be able to use the construction crane for the installation on the 17th floor.

Further joint projects with PLEXIGLAS® are planned

Gerold Wimmer from Berndorf Metall- und Bäderbau and Moritz Meinesz from Hydrosight make the perfect combination. This is mainly due to the fact that the Austrian’s stainless steel pools go very well with the German’s PLEXIGLAS® designs. Together, the specialists are already planning new, even more spectacular bays for swimming pools at dizzying heights. So we will have to wait and see what they will come up with next.

Stronger than glass

Up on the 17th floor, the fitters then sealed the structure with a high-pressure silicone dosing machine. Silicone is particularly suitable for this application since it ensures tight sealing and remains flexible at temperatures ranging from minus 30 to plus 60 degrees. “The fitters from Berndorf were very wary of venturing onto the platform at this staggering height,” remembers Meinesz with a smile on his face. “But nothing bad can happen. The panels made of 88 mm thick PLEXIGLAS® are considerably stronger than glass. That is an important safety factor.” And a factor not to be underestimated when a transparent pool with 54,000 liters of water protrudes out of the building 17 floors in the air.