Kurhaus – Copper & Silver Art

 

The iconic Kurhaus in Scheveningen (NL) has a new look. The 3000 m² roof surface received a new covering. The old roofing with copper layer was weathered by sand and sea wind and due for replacement. For the refurbishment, roofer BOKO selected the SOPREMA Copper Art roofing

A rain of sunbeams covers the roof of Scheveningen’s major attraction. The tent roofs reflect a copper glance. An employee is finishing the last details just before the final acceptance. The synthetic roofing incorporates metal particles which give a classical, copper look reflecting in the sun. Klaas Toornstra is a proud man as he looks up to the Dutch tricolour blowing in the stiff breeze. As a technical consultant for BOKO he started this prestigious project in the summer of 2016: the roof refurbishment of one of the most famous buildings along the Dutch coast.

Toornstra reflects on the job: “It was a challenging process as you have to reckon with weather conditions. Besides, the roofing is submitted to stringent requirements. Together with the building team made up of DakbestekPleijsier Bouw, BOKO and SOPREMA, we have drafted and implemented the action plan.”

MUCH MORE THAN STANDARD WORK

Technical design and building assistance was assigned to the consulting firm Dakbestek. Julien Stevens, Director of Adviesburo Dakbestek, explains: “A prominent building like the Kurhaus demands a specific approach. The Amrâth Hotel Group, the Kurhaus owner, had a wish list of requirements to comply with, more particularly out of the esthetical point of view: the new roofing should not denigrate the classical character of the edifice. Furthermore, there was a preference for a PVC roofing, also for the highest roofs. We had to search for a copper coloured covering.” According to Stevens, Dakbestek added even technical requirements during the design phase: “The new roofing should be fixed on a bitumen substrate. A second demand was full-surface gluing to resist to storm weather and avoid tunnelling. This combination of technical and esthetical characteristics is rare.

ROOFING THAT CAN WITHSTAND QUITE A LOT

The execution of the refurbishment works was awarded to the roofing firm BOKO. The PVC strips were tailor-made for this project allowing BOKO to comply with the full-surface gluing requirement. Toornstra explains this choice: “This part of the roof, facing the seaside, undergoes constantly sea wind. So, we needed a durable covering that could withstand quite a lot. We opted deliberately for double-sided bonding to ensure that the old layer was stormproof with respect to the sub-construction. This way of working avoids unsightly protrusions of the fixation. Of course, we wanted to preserve the authentic look.”

FOCUS ON GLUING

After peeling off the old copper layer, BOKO first fastened mechanically the existing roof covering. Then a new self-adhesive underlayer was fixed on the bitumen roofing. Toornstra explains: “We applied in our workshop a contact adhesive on the Copper Art roofing strips and covered the strips with a release film so that they could be rolled up again. On the building site, we only had to install the strips. After rolling out the pre-glued Copper Art on the self-adhesive substrate we could ensure a perfect bonding.

According to Toornstra, the whole process has been quite a journey. The delay between applying the contact adhesive on the substrate and placing the Copper Art top layer had to be reduced to a minimum. “The wind may blow sand between the two layers which weakens the fastening. As we kept the time between the application of the contact adhesive and the installation of the Copper Art to a minimum, we have been able to cope very well with this problem”, tells Toornstra.

NATURAL OXIDATION

SOPREMA was not unknown to BOKO. They worked already together in other projects. The Copper Art roofing is a relative new product on the Dutch market and has not frequently been applied yet. BOKO recognised immediately the added value of this in Italy developed roofing material. Toornstra comments the specific characteristics of Copper Art: “It is a synthetic waterproofing membrane incorporating fine metallic particles. The esthetical aspect is similar to that of a real copper roof. Moreover, this membrane undergoes the same natural oxidation process as real copper. Furthermore, Copper Art is recyclable. SOPREMA delivered for this project a tailor-made, durable and sustainable product. We can look back on a very successful collaboration.