Hybrid window frames for landmark residential tower

Rotterdam's STACK residential tower features duet wood-aluminum façade frames and interior frames and doors from Kievit Kozijn. "This window frame fits the current need very well," says Kievit.

The seventy-meter tower has 957 façade frames, 265 interior frames and 226 interior doors. The choice for the facade frames was duet's hybrid frames. Director Robert van Wijngaarden of duet and Kievit Kozijn: "We do a lot of business with main contractor VORM Bouw and know each other well. In 2019 came a request for this project: whether it was possible to use duet window frames for this. This is because these are easy to integrate into modular construction and interesting in terms of investment costs. Thereby, because of the aluminum profile, the outside requires hardly any maintenance, while the inside can be painted in the desired color."

More wood in construction

In addition, the product plays very much to sustainability. The wood component minimizes the proportion of aluminum, and almost half of the aluminum in these frames is recycled. In addition, "more wood in construction" is now a trend. Duet involves sustainably produced wood from European forests and plantation wood, which reduces the number of transport movements. Van Wijngaarden: "We see that this window frame fits the current need well. The product has been around for a while: I brought it back from Switzerland in 2007, but at that time the market here was not ready for it. Gradually we saw that sustainability and recyclability were becoming more and more important. So in 2016 we put the product on the market again and now it is running well, with many great orders on the horizon."

On the STACK project, the frames were painted in the buyer's desired color and delivered to the precast builder glazed. The elements were taped with felt to protect the aluminum and glass. Then the complete facade elements were delivered just-in-time to the construction site. When the residential tower was nearing completion, this protective layer was removed in one go.

Collaboration in preparation, engineering and production

Such a large project involves a great deal of preparation, planning and engineering. Van Wijngaarden: "In a project as large as this, where attention needs to be paid to various building physics properties, we always engineer along. We have been trusted to do that." All window frames, interior frames and doors were produced at Kievit Kozijn's own production site in Ridderkerk. Van Wijngaarden looks back on the project with satisfaction. "It is nice to see that in a short time we worked together with a fine team, both in preparation, engineering and production, to shape the project. That way we were able to get the best out of each other."