Living atop the Scheldt Square

On Scheldeplein, the complete renovation of the building once known as Sieberg's Glass Palace was recently completed. Client Caransa Groep commissioned DOK Architects to create a design that restored the building's original appearance at this prominent location. In addition, nine luxury apartments were added on the roof, some of which have a patio or roof terrace. To make this elevation possible, Reppel from Dordrecht provided a light floor construction on the new top floor.

Reppel specializes in floor systems for new construction, renovation and transformation projects. Among other products, the company supplies the well-known LEWIS® Dovetailed Sheets® and HODY® dovetailed concrete floors. "To create a strong but not too heavy floor on Scheldeplein, we chose our OP-DECK® system," says Niels de Bruin, Technical Manager at Reppel. "The building received a completely new steel roof structure that was already extra insulated for sound, because of the underlying bowling alley. Earlier in the construction process, the building's foundation had already been reinforced to support the additional residential floor." The residential program on the building's roof consists of four patio homes on the Geulstraat side and five terrace homes along Geleenstraat. 

OP-DECK® is a lightweight, insulated low-height concrete floor system that allows for large free spans. The system consists of a sandwich panel of thin, profiled steel plate with PIR foam insulation. The panels lie on top of the steel structure. "EPS blocks applied to the panel provide further weight reduction and form the mold for the structural T-rib concrete floor," explains De Bruin. "On the EPS blocks is a top reinforcement and between the EPS blocks is the bottom reinforcement. With this floor system, you actually combine the advantages of a steel plate concrete floor with a rib floor into an extremely lightweight solution."

Normally, a concrete quality C28/35 with a weight of 24 kN/m3 is used for the concrete floor. De Bruin: "But for the Scheldeplein we were still just above the required weight with this. That was solved by working with lightweight concrete of 18 kN/m3. The spans on this roof are 5.5 meters, but with this system spans of 10 meters are possible. These are considerable distances when you realize that the entire OP-DECK® floor package on Scheldeplein is only 288 mm thick! With this floor construction, the OP-DECK® floor has an Rc value of 6.8. The calculated floor load on this project is 2.25 kN/m² for the houses and 2.5 kN/m² for the terraces." 

An additional challenge was the various penetrations that housing entails. "Water and electrical lines are no problem at all, but it required a little more attention to neatly finish the down pipes and drains and route them under the floor. We also had to make 22 crawl hatches. A crawl space was created under the entire roof floor that can be accessed through crawl hatches in the homes for maintenance purposes, for example." 

The OP-DECK® system proved to be the perfect solution for this top-up project, according to De Bruin. "We often apply this system to parking roofs, such as on top of a shopping center. We then combine it with, for example, a Triflex system or Zoontjens' parking roof tiles. At Scheldeplein there were similar floor specifications: a low own weight, high insulation value, large span, high allowable loads and a fire resistance of 60 minutes. In addition, the system is quick and easy to install without propping up to 5.5 meters. The capabilities of this floor system made it a perfect fit for the design of this challenging project."