Tight and secure thanks to sophisticated sealing advice

Zwapex Afdichtingtechnieken was approached by Bouwcombinatie Wonderwoods to provide sealing advice for the air sealing and waterproofing of the facades in the Wonderwoods project in Utrecht. In collaboration with supplier Celdex, this advice was further developed. "Wonderwoods is a comprehensive project in which our extensive expertise comes in handy to the maximum extent."

Zwapex has been the sealing partner for construction and installation companies in the Netherlands for 50 years. "We have extensive knowledge in the field of joint seals, structural fire protection and air sealing," says Operations Director Patrick Jansen. "Commissioned by Bouwcombinatie Wonderwoods VOF (Kondor Wessels Amsterdam | Boele & van Eesteren), we are providing both the air sealing, waterproofing and aesthetic finishing of the Wonderwoods towers. The sandwich facade elements of both residential towers are produced by Westo Prefab Betonsystemen in Coevorden, where the window frames, insulation and inner and outer shell are also pre-assembled. Immediately after assembly and cleaning and blasting, we apply our seals to the bag field, where the façade elements are collected on special transport sleds."

Air and driving rain sealing

The prefabricated facade elements are fitted with Celdex sealing products by Zwapex. "Whereas a Pre-Seal LF provides air sealing and insulation on the inside, EPDM Soft guarantees excellent driving rain sealing on the outside," says Bertus van Atten, Account Manager at Zwapex. "In addition, we apply Butyl tape 70S as a water barrier for the sandwich elements." Biggest challenge here are the weather conditions. "For applying the primers, a dry surface is essential," Jansen says. "In addition, it must not be too cold. That's why we have to coordinate our assembly times closely. We operate on average three days a week on the bag field to meet the weekly production. Each floor has a cycle of one to two weeks, which fortunately gives us some slack on the schedule."

Aesthetic sealant joints

Thanks to Celdex sealing products, scaffolding can be built without scaffolding, Van Atten emphasizes. "From the bag field, all façade elements are transported just-in-time to the construction site, where they are lifted by crane and fixed into the concrete shell." The elements are then poured and fireproofed on the inside by Zwapex. "In addition, we apply aesthetic sealant joints at the window sills, sills and stairwells. On behalf of De Groot & Visser, we also seal all the facade frames. To keep all work going exactly according to schedule, we work on Wonderwoods with about six people every day."