Façade insulation system brings sustainability and fire safety together

On the Dender in Aalst, Kaai 33 is rising. The residential project brings 29 residential units in a high-profile architecture. The construction takes place in a challenging context, with severe price fluctuations and on the eve of new fire safety requirements. WALLTEC BLACK proved a partner for the construction team to meet these challenges.

Beacon on new Aalst ramblas

Together with the city of Aalst, project developer Vestra, ESTE architects and contractor E. Rombaut are writing a new story for the quays in the industrial city. With the Kaai 33 project, the remonte of the axis between the city park and the city center along the Dender begins. To fulfill their commitment to sustainability and fire safety for Kaai 33, the designers selected URSA's WALLTEC BLACK insulation.

Kaai 33 manifests itself as a ship, just docked on the banks of the Dender. With those poetic words, the project website of the new residential project opens. The renders leave little to the imagination and confirm a solid architecture that gives the former industrial site on the Dender a strong identity once again. "That was also the starting point for our design," opens Peter Flamend, architect partner at ESTE architects. "Responding to the RUP 'Uitbreiding Stadspark', we came to this design together with the city of Aalst. In our vision, we wanted the project to pay tribute to Aalst's industrial past. This translates into raw building materials, such as the red brick, the large concrete slabs for the pavement or the metal cladding for the top floors. Those top boxes mark the end point of the building and at the same time are a beacon when entering the city." 

Quay 33 represents the first project of a new development between the city park and downtown. The city will also later reconstruct the quays with the intention of turning them into a ramblas between the city's two attractions.

Fireproof in all simplicity

Not only from an architectural point of view, but also in terms of sustainability, Kaai 33 scores high marks, thanks to its good energy performance and the choice of sound materials. For the insulation of the outer shell, ESTE architects chose mineral wool for two reasons. "First, because of its durability," refines Flamend. "We at ESTE architects are not fans of chemical insulation materials which, by the way, are not recyclable. But also because of fire safety. Prompted by the stricter requirements for facade insulation in the new Fire Safety RD, we were looking for an insulation solution that does not require compartmentalization in the insulation shell of the exterior facade. This makes it much easier to coordinate the various contractors. Hence the choice of mineral glass wool."

Fine first introduction

At the suggestion of building materials dealer Van Biesen - Everaert, contractor E. Rombaut chose Ursa's WALLTEC BLACK. Site superintendent Gunter Vereecken has completed the load-bearing structural shell and is now in the process of installing the facade insulation and facing brick. "It is the first time I am working with WALLTEC BLACK of 18 cm thickness," he confesses. "In itself, it is an easy insulation system to install. We attach the boards with dowels. In principle, a 6 cm deep anchorage is sufficient, but because plugs of 24 cm are currently hard to find on the market, we work with plugs of 26 cm. An advantage of this soft insulation is that it easily adapts to unevenness in the supporting structure. With hard insulation boards you always have to cut to get a perfect fit. One point of attention is that we have to cover the insulation when it rains. That does distress me a bit, but otherwise the first introduction goes fine." 

The insulation gets protection with a red facade brick. "Remarkable about this are the vertical streaking layers that finish each floor. After all, it's about 600 m² out of a total of 1,800 m² of masonry."

Forward-looking purchases

Frederik Van Biesen remembers well the request from contractor E. Rombaut. "The first contacts dated back to late 2021. The starting point was a sustainable material that could easily meet the new fire requirements and, above all, offer some certainty of a fixed price. The big challenge for us was to offer the same R-value as PIR insulation, without deviating too much from the thickness of that insulation material." Thanks to this proposal, the supplier gained confidence for the entire insulation solution in the project, including the accessories. "In the process, the contractor also played it safe and ordered some of the insulation ahead of time and stored it on site. In this way, he himself also anticipated the current price uncertainty. We have been working with the contractor for several years and also have a lot of material in stock ourselves, which allows us to deliver quickly."