Amsterdam-based architects UNStudio transformed a wartime concrete bunker into a poetic, multipurpose, and thoroughly modern monument—without eradicating the original.

In the middle of a field in Vreeland, blotting the kind of rustic 17th-century Dutch landscape familiar from Rembrandt etchings, stands an implacable concrete war bunker; a conservation order forbids its demolition. The owner of the land—which is now used for polo matches—asked UNStudio to transform the bunker into a place where he could host friends, hold meetings, watch polo, and enjoy the country views. The result is the Tea House on Bunker, an elegantly contorted structure whose daring 36-foot cantilever springs directly from the earthbound bunker, effectively lifting the entire building into the sky, mirroring blue in its textured steel skin.

“We started by analyzing the bunker itself, and the views from it,” says Ben van Berkel, a UNStudio principal. “The solution that we came up with was to hang the Tea House from the old concrete structure, bridging out beyond the original walls to form a space with a huge window for people to see the landscape.” The single floor-to-ceiling window, 49 feet wide and floating just over 7 feet above the ground, dominates the interior structure (and can be completely removed in summer, dissolving the barrier between inside and outside); there’s also a small kitchen and a bathroom, allowing the Tea House to function as a guest house, as well as a meeting space and viewing platform.

“Our strategy was to cover the bunker, yet not cover it,” says van Berkel. “On the outside, just as with the bunker, the Tea House has a totally coherent structure. It’s a sculpture that grows out of another sculpture. There’s no seam or gap, and it’s all welded together as one entity.” The cladding was formed from sheets of steel welded seamlessly, punched with dots to catch the light, and folded around the frame. The welding took a year to complete. Patches of the bunker’s concrete have been left visible, so as to create a visual link between the old and new; the climbing plants that were working to cover the old structure have also been permitted to creep onto the new gleaming steel façade. “It’s as if you move from the archaeological aspect of the bunker to its new evolution in the Tea House,” says van Berkel.

The Tea House, he continues, represents more than a building: “It’s a thing in itself, a piece of art. Actually, we wanted to create a new bunker—after all, you can be really secluded here, apart from the one window. The Tea House has the same oblique quality as the bunker, and the steel exploits those angles by reflecting every change in the light. I’d say that what we’ve done is to reframe the original building. Restoration I don’t really believe in. When you restore a building, you always put something new on top of it anyway. Much more than restructuring, I like the idea of reframing.”