Thrills on the 17th Floor

In the Clarion Hotel in Helsinki, the pool protrudes five feet out of the building – 17 floors up.

Whoever dares to look down when swimming over the transparent floor made with POLYVANTIS acrylic block 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 164 feet 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 1,907 cubic feet 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 13 feet and a length of roughly 33 feet. Moritz Meinesz and his company Hydrosight were brought in to add that special something, the transparent floor which protrudes five feet out of the building.

An undistorted view

The company from Emmerich am Rhein specializes in underwater windows made of block manufactured by POLYVANTIS. "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 acrylic block, 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 block, "since it is really easy to combine stainless steel with POLYVANTIS acrylic block."

Clear view of the old harbor

Guests at the Clarion Hotel in Helsinki can enjoy a great view over the city and the old harbor from the pool.

© FI / Helsinki, Hotel Clarion,

Small company with a big effect

Moritz Meinesz (center), Managing Director of Hydrosight GmbH, with two employees in the steel frame, into which the two blocks of acrylic were installed.

© Hydrosight GmbH

A head for heights is a must

On the 17th floor, the stainless-steel pool protrudes five feet out of the building like a balcony - certainly not everyone's cup of tea.

© FI / Helsinki, Hotel Clarion,

Comfortably warm

To ensure that the water in the pool does not cool down even when it is freezing cold, the structure must be well insulated. Compared to glass, acrylic has very good insulating properties. The panels can keep the warmth inside, even when it is bitterly cold outside.

© FI / Helsinki, Hotel Clarion,

A heavyweight pool

The floor and one of the sides of the L-shaped pool are each made of a large, transparent block of ACRYLITE® acrylic. The 11.5' by 3.3' and 11.5' by 3.6' large panels were placed into the stainless steel pool on site in Helsinki. This was a logistical challenge, since the two blocks of acrylic 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.

Unsurpassed Strength

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 3.5" thick acrylic block are extremely strong. That is an important safety factor." And a factor not to be underestimated when a transparent pool with 11,878 gallons of water protrudes out of the building 17 floors in the air.

Further joint projects with PLOYVANTIS acrylic block 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 acrylic block 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.


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Thrills on the 17th Floor