Optimal wind and rain sealing, even in prefabricated construction

With the 2030 climate goals on the horizon, increasing attention is being paid to the importance of and opportunities for building insulation and air sealing. Synchronous to this, attention to prefabrication is growing. A logical development, according to Henny van der Heijden of Celdex, because it guarantees a constant, high building quality. "Production takes place in the factory, under the best (climate) conditions. Moreover, production can already be started while the foundation is still being poured on site. This leads to significantly shorter construction times, thus lower costs. Also, fewer skilled hands are needed on the building site, failure costs are reduced and building in the factory is safer. HSB, frame and concrete frame manufacturers are increasingly able to meet demand. Finally, in combination with good air sealing, requirements such as BENG, Zero-in-the-Meter and BREEAM-NL can be excellently met."

Like construction, the sealing of building elements is moving more and more to the factory. This places new demands not only on assembly and work preparation, but also on sealing products, Van der Heijden said. "Celdex has seen the prefabricated building trend coming for some time and has extensively surveyed the needs and challenges in this area. Among other things, this has led to our Seal4Prefab concept, with which we provide construction stakeholders with all the essential building blocks to achieve and demonstrate the desired performance in airtight construction."

New generation of 'dry' sealing products

In practice, prefabricated construction is often not prefabricated sealing. Especially when it comes to wind and rain sealing products, Van der Heijden notes. "For example, because although complete facade elements, interior cavity walls and frame elements are prefabricated, wet sealing materials such as PU foams, sealants and coatings are still used on construction. Our main goal is to include applicable sealing products in the precast process as well. For example, various "dry" foam tapes such as Pre-Seal, Panelseal and Stelkozijnband are already prefabricated at the factory. In addition, on the building site, large joints up to 120 mm and penetrations can be sealed dry and weather-independent with Airseal Strips. Thanks to our new products, tolerances can be accommodated even more easily, installed more easily and finished airtight. Moreover, excellent sealing and insulation are combined in one product. All Seal4Prefab sealing products have been extensively and successfully tested for durability, wind and rain tightness and workability, guaranteeing high performance. Considerable savings in application time can be made in construction. Moreover, construction dust and weather conditions no longer affect the quality of the sealing products."

Preparation and engineering

Important parts of Celdex Seal4Prefab are knowledge transfer and quality assurance, but also proper preparation and engineering. "Based on, for example, the best requirements and building drawings, we give advice on the best fitting sealing products and (prefab) assembly," says Van der Heijden. "For example, how is water management handled? And airtightness? What performance is demanded? Where are the critical points? What tolerances do HSB, frame and concrete frame manufacturers expect? Are we dealing with uniform joint dimensions and/or can this be realized? But also: which assembly sequence is best to follow, for an optimal result? If desired, we can test materials in advance in a critical building detail for wind and rain tightness. We can also issue a performance guarantee for this." 

Before moving on to precast production, Celdex organizes a toolbox meeting for the processors. "Before assembly begins, a toolbox meeting is also set up for the precast assemblers, focusing in particular on inspection and repair in the event of unexpected transport damage. All processes are carefully recorded in partial reports, which together produce a single report for private quality assurance."

Reference project: The Cube

The Seal4Prefab concept was recently successfully applied in student housing complex 'The Cube' in Utrecht Overvecht, which consists of 639 student houses, a bicycle basement and 1,000 square meters of public facilities. Celdex was involved at an early stage to help think about the air and rain sealing of the HSB façade elements in particular, says Van der Heijden. "The HSB elements were already fitted with frames, ceramic stone strips and Celdex sealing products in the factory. This made scaffolding-free construction possible. After all, no more cracks and seams had to be sealed from the outside. A specific wish of our client, which we were able to fulfill perfectly with our products. Moreover, we agreed on an interval for construction checks, which were included in the construction file and handed over to the client upon completion."

Another great reference project for Seal4Prefab is educational and cultural complex Amare in The Hague. Currently, Celdex is involved with this concept in residential buildings Doktoren in Antwerp, Wonderwoods in Utrecht, De Kwekerij in Utrecht and various plots in the Werkspoor area in Amsterdam.  

https://celdex.nl/