Platform on new construction, renovation, restoration and transformation
To secure the monumental part of Paleis Het Loo, the window frames are equipped with rear windows with resistance level RC 4 (burglary). The frames are made of steel and glass and form a thermal shell with the monumental window frame. Jonkers Bouwmetaal produced and assembled hundreds of windows. In addition, the specialist from Urk supplied various steel (entrance) doors including hardware. "Engineered in 3D, produced to size and SKG-certified," says project manager Maarten Jonkers.
The hundreds of rear windows in the monumental main building form the largest volume of the order, which was won in 2019. "For our company, Palace Het Loo is a unique project, although specials are more often a reason to choose Jonkers Bouwmetaal," Jonkers says. "You can imagine that a glazed steel window frame of 3 by 1.5 meters - and there are many of those at Palace Het Loo, is not easy to assemble everywhere." In addition to being custom-engineered and manufactured, assembly was also done to size, using prefabrication. "We work for these reasons with our own people and special equipment, such as mini cranes and project-specific assembly tools. Nothing should be damaged in an existing museum environment, and security against burglary or fire is precisely the reason these materials are built in."
Jonkers Bouwmetaal is the supplier in the main building of the rear windows and steel doors. "Some objects are clad in wood to preserve the original appearance and have a burglar-resistant and sometimes even compartmentalizing function in the context of fire," Jonkers says of the doors. "There are also arched doors among them, so the connections require even more attention in the context of burglary and fire protection. We build in the hardware ourselves, including access control systems."
All objects are SKG-certified, which means the hardware is officially tested for strength and durability. "This form of integral steel construction is a real specialty. Especially the connections and tolerances are extremely important. After all, you are making a contemporary shell of window frames, with high burglar and fire resistance, in an ancient building."
Insulated bluestone sills: 'instant energy savings'
For the well-known thermal bridge of natural stone sills, Duriso developed an innovative solution, a sandwich element composed of two layers of Belgian bluestone and insulation material. This was applied twice during the restoration of Paleis Het Loo.
A 'Duriso' consists of an insulated bluestone sill. The UV-resistant, double-sided adhesive insulation layer separates the inner and outer parts of the sill, preventing a thermal bridge. This keeps energy on the right side of the facade. In addition, condensation is prevented. "Natural stone sills beautify door and window frames and prevent moisture from penetrating them," says Dick van den Brink of Duriso. "Because all our Belgian natural stone products are custom-made, the sills are applicable in new construction and buildings to be preserved. All details are provided. Architects meet the most stringent energy-saving requirements with these innovative bluestone sills. In addition, they are naturally maintenance-free and will last more than 100 years."
Duriso's product is sustainably sourced, with minimal transport distances, and processed in the Netherlands. "Of course, we ourselves believe that this solution should be used much more often. Implementation is cost-effective and nowhere does insulation deliver a greater effect than in monumental restorations, such as Paleis Het Loo."
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