cero sliding window - loft house Molenpark
From the planning phase right through to construction - Solarlux has been very supportive right from the start
Eva Sydow, bb22 architekten + stadtplaner
cero sliding doors - Molenpark loft house project, Frankfurt

If you stand on the shore of the repurposed Offenbach Harbour, you’ll enjoy great views across the water towards the Frankfurt skyline and Offenbach Harbour square. This is where bb22 architekten + stadtplaner is building the Molenpark loft house over six flexible floors. Not only is the interior open-plan, but the entire south façade opens up out onto the water. The planners’ desire: as much transparency as possible.

We spoke with Jan Schulz and Eva Sydow from bb22 about seizing opportunities to resolutely follow through on their architectural idea, the design consequences, and the excitement felt when installing glass elements covering several square metres.

Find out more by watching the video or reading the full interview.


Jan Schulz and Eva Sydow bb22 architekten + stadtplaner

Montage Schiebefenster cero im Lofthaus Molenpark
Montage Schiebefenster cero im Lofthaus Molenpark
In this project, you are the client and the architect at the same time. How did that come about?

Jan Schulz: “That wasn’t the original plan. The design was created to be completed with an investor as is customary. But they were not able to realise the project after all. In order to build the design anyway, we looked for comrades-in-arms. In the end, a consortium was formed comprising of architects and managing directors from a marketing agency.

The community of builders is a stroke of luck since they all share high design standards. This has made it possible to implement ideas that might have otherwise fallen victim to the red pencil in a classic investor model.“

Montage Schiebefenster cero im Lofthaus Molenpark / Einbau der Glas-Elemente
Montage Schiebefenster cero im Lofthaus Molenpark / Einbau der Glas-Elemente
Tell us more about the project

Jan Schulz: “The loft house is a key element at Offenbach Harbour. The creative centre of the Rhine-Main region is emerging here. The project acts as an interface between the new-build Art and Design University on the mainland and high-quality residential development on the harbour island.

The project bridges the gap with flexible floor plans that allow for both office and residential use. This flexible use is possible thanks to floor heights of just under five metres on the ground floor and a good three metres on the upper floors.

In terms of design, the project makes full use of the potential afforded to it by its location on the water. The front – which faces south and the former harbour basin – features balconies as wide as the building. The façade behind it is completely glazed. The glazing runs around both corners of the building, giving the impression of being outdoors even when inside. The large-format cero sliding doors enhance this feeling further.“

Montage Schiebefenster cero im Lofthaus Molenpark / Einbau der Glas-Elemente
Montage Schiebefenster cero im Lofthaus Molenpark / Einbau der Glas-Elemente
Was Solarlux the perfect choice for you right from the start?

Eva Sydow: “To be honest, no. In the planning stages, we were initially considering a competitor. But we already had contact with Axel Maurer (Solarlux). I knew him from the Marina Gardens project, which was built on the opposite harbour bank, right on the new Hafenallee. Solarlux bi-folding doors are installed there and this was something I remember fondly. While discussing the Molenpark loft house, Axel Maurer introduced us to cero sliding doors and together we developed ideas about what they might look like in practice."

Jan Schulz: “Ultimately, it was Axel Maurer’s commitment and enthusiasm that tipped the scales in favour of Solarlux. We always shared a feeling that we were all working together and that both sides wanted to see a great project come to life. After all, that’s what you want as an architect."

Eva Sydow: “A visit to the factory in Melle Germany was also crucial for me. Since we were talking about fitting five-metre-high sliding doors on the ground floor, I was impressed when I pushed a sliding element of that size myself and felt how well it moves."

Montage Schiebefenster cero im Lofthaus Molenpark
Montage Schiebefenster cero im Lofthaus Molenpark
What were the planning consequences given that you opted for cero?

Eva Sydow: “A few tricky points arose during the detailed planning stages for the corner sliding door front, particularly in relation to the design requirement to have as much glass and as few profiles as possible.

The first issue was shading: Since sunshade systems all come with a narrower grid for guide cables or profiles compared with sliding doors, we decided against having one. Solarlux has incorporated different solar control glazing into the sliding doors, depending on where they are fitted, and the cantilevered balconies also provide shade. Nevertheless, we still had several discussions with the specialist engineers.

Two further details mainly relate to the side glazing. Given the narrow door profiles, it was not possible to install a guardrail here. We then decided to hang it from above instead. Incorporating drainage was also not entirely straightforward.

In contrast to a standard product, deciding to opt for such a product extends from the planning phase right through to construction. Solarlux has been very supportive right from the start."

Montage Schiebefenster cero im Lofthaus Molenpark / Kran hebt Glas-Elemente
Montage Schiebefenster cero im Lofthaus Molenpark / Kran hebt Glas-Elemente

Eva Sydow: “At the moment, we are completing preliminary work, such as installing the rails and posts. Cooperating with Solarlux on the construction site is going very well.

In terms of the installation, we were given precise instructions on what we had to do. Since we are building very close to the shore, this includes providing a surface on which the truck-mounted crane can stand and move – without falling into the harbour basin. What’s more, the shell of the building must not be scaffolded to allow the panes to be lifted into the openings.

We are quite excited about the large glass elements being installed. With sizes of 2.50 x 3 metres and 2.5 x 4.5 metres on the ground floor, this is certainly not an everyday occurrence."

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The window elements have now been fitted. A topping-out ceremony was held when the panes – several square metres in size – were inserted into the façade by crane. Where previously there was a shell with widely projecting concrete ceilings, we can now start to appreciate the quality of the finished building.

Montage Schiebefenster cero im Lofthaus Molenpark / Einbau der Glas-Elemente

Large glass elements are inserted into the openings by a truck-mounted crane.

b22 architekten + stadtplaner
b22 architekten + stadtplaner
Eva Sydow (2nd from right) and Jan Schulz (center) discuss the design with their planning team. Copyright: bb22 architekten + stadtplaner

bb22 works from regional, urban and structural design to detailed implementation at different scales and with interdisciplinary planning teams. More at www.bb22.net