Durable magnesium oxide sheet 'protects' apartment complex residents

Woonstad Rotterdam is constructing 52 new apartments on the corner of Soetendaalseweg and Ruivenweg in Rotterdam. The first pile was driven at the end of 2023, with completion scheduled for early 2025. Thanks to Vadeko's HSB elements, the building was made wind and watertight in no time. And fire resistance is also guaranteed. Even more than that. Meet Cem-Rock Extreme - Wettershield from Tholin, a virtually incombustible magnesium oxide board.

Prefabricated construction is still gaining popularity. "And especially prefab construction in wood," notes Wiebe Postma, director of Vadeko. "Wood stores CO2, it is lightweight and therefore much more sustainable than a precast construction method in concrete. We also load 36 HSB elements onto one truck, whereas in concrete you can only load four walls. So it also saves significantly in transport movements." Vadeko specializes in the production of wood frame structures for wall, floor and roof, and now does so from two production sites. 

High fire requirement

Commissioned by Riz Bouw, we were asked to provide the facade sealing for the new apartment complex in Rotterdam, Wiebe continues. "The HSB elements were produced entirely under conditioned conditions in our factory. Because a relatively high fire requirement was required, we chose to apply Cem-Rock Extreme - Wettershield fire class A1 on the outside of each element. It is a board that lends itself ideally to prefabrication, as the board is easy to process in the factory." Vadeko has been working with Tholin's products for a long time to meet increasingly high fire resistance requirements. "They are knowledgeable and assist us with appropriate advice for the more complex issues. That just works very nicely," Wiebe believes. "Just like the Windstopper that we have been using for a long time, we also see more and more applications for this Cem-Rock Extreme - Wettershield." 

Lighter and stronger

Tholin supplied approximately 1,200 m2 of Cem-Rock Extreme - Wettershield for this project. The board was incorporated on the outside of the HSB element to prevent fire spread. This is because the facade will be finished with mostly a wood cladding and a small portion of masonry. "The Cem-Rock Extreme - Wettershield is a magnesium oxide board and that has a number of advantages over a regular cementitious board," says Bart Jannink of Tholin Construction Products. "For example, the board is lighter in weight, less prone to breakage and highly resistant to moisture. Furthermore, Cem-Rock is extensively certified (EPD and ETA), has the highest fire class A1 and above all is also favorably priced. The board can function for up to a year as a temporary facade, while waiting for the definitive ventilated facade cladding. Especially in the case of extensive prefabrication of the facade, such as in the apartment complex in Rotterdam, this is of absolute added value."

Finally, Cem-Rock Extreme - Wettershield is also an environmentally responsible choice. "The boards are manufactured from natural materials, without the addition of harmful chemicals. Their production is also generally less energy intensive than that of cementitious or fiber cement boards. In short, an excellent choice in several respects."