Sophisticated air and water sealing for tallest green building in the Netherlands

Upon completion this summer, Wonderwoods in the heart of Utrecht will be the tallest green building in the Netherlands. Together, the two impressive residential towers of 105 and 70 meters high form a vertical park. Already in October 2020, Celdex was approached by construction combination Wonderwoods VOF (Kondor Wessels Amsterdam | Boele & van Eesteren) to provide sophisticated air sealing, driving rain sealing and optimal insulation of the facade elements.

Although both towers differ in height and appearance, they have more in common than you might think. Wonderwoods was built scaffolding-free with a facade consisting of prefabricated facade elements. "In the preliminary process, we sought a uniform connection of the façade elements," begins Henny van der Heijden, Business Development Manager at Celdex. "By keeping the joint dimensions, details and seals largely identical, the applicator was able to process the precast seals for both towers even more efficiently." Never mind that Celdex worked out the solutions entirely in 3D. "It obviously has everything to do with the complexity of the project."

Seal4Prefab sealing system

Because Celdex was already involved in the technical orientation phase, it was able to make adjustments where necessary to achieve the most optimal end result. Van der Heijden gives an example: "On our advice, the structural engineer installed the special Z façade anchors in a slightly different position so that they did not negatively affect the air seal. We then selected the right products within our Seal4Prefab sealing system." A variety of Celdex products were used at Wonderwoods. "In both towers, Pre-Seal LF provides the air seal and insulation on the inside, while EPDM Soft provides the driving rain seal on the outside. These products were factory prefabricated on top of the horizontal water barrier. On site, safely lined up from the floor level, the cross junction between four elements was sealed with our Butyl tape 70S and EDPM Soft. It ensures that the air and driving rain tight connections continue in all directions." 

At Wonderwoods, in addition to the mix of standard Celdex products, custom sleeves were used for the columns and beams. "The requirement of at least 600 Pascal for air and driving rain sealing was demonstrated via a mock-up, in which the critical cross connection as well as the Z-anchors were extensively tested. The setup achieved 650 Pascal without any problems."