Renovating a house layered with centuries of history is a delicate balancing act. While too many interventions can compromise the spirit of a structure, too little can risk its collapse under the weight of time. For Prague-based architecture studio OOOOX, the Hradby Residence in the Czech Republic posed one such challenge. A former fortification guardhouse, whose roots date back to the Middle Ages, and features vaulted stone ceiling on the ground floor, painted wooden beams upstairs and an original tiled stove, was in an urgent need of restoration. “The goal was to restore as many elements as possible and to complement the entire space sensitively with a modern interior,” the architects note in the press release. This mindset defined the entire project, resulting in a residential design that resides at the cusp of the historical and the contemporary.

When OOOOX was commissioned for the project, the layout of the floors had already been established. The entrance level was segregated into a living room, dining area, kitchen and a guest room converted from an unused garage. Upstairs, another living space occupied the floor with bedrooms and bathrooms. The building’s damp masonry and fragile historic fabric, however, demanded more than surface repairs. OOOOX—helmed by Radka and Jakub Valovi, and known for its meticulous approach to renovation architecture—channelled their characteristic balance of sensitivity and technical precision to preserve and fortify as much of the original structure in the redesign.

The team stripped away damaged plaster to allow the original masonry to ‘breathe’, adding rehabilitation plaster only to the lower portions of the perimeter walls on the ground floor. In some areas, this process is repeated multiple times to draw out as much moisture as possible. Other internal plasters are glazed and finely polished to create a play of reflections and textures. Vaulted ceilings are reinforced with helical braces, while light outlets are strategically introduced from above to preserve the visual integrity of the arches. The stone architecture is partially exposed, the walls’ rough texture offset against smoother plaster surfaces.

A staircase leading to the upper floor, initially in a very poor condition, is renovated and finished with an illuminated handrail that casts dramatic lines across the exposed stone wall. The stairs required ventilation too, owing to the old masonry that needed constant care. To bring modern efficiency without disrupting the past remnants, the entire interior was fitted with a recuperation system in which the ducts are concealed within the structure and finished with cast-iron grills to maintain the building’s visual character.

As one moves upstairs, the material palette and subsequently, the atmosphere noticeably shift. Timber takes over stone to offer warmth and a lighter ambience. The asphalt coating was cleaned off the original floorboards, which were then brushed by hand and oiled to a muted grey. The preserved period tiled stove is paired with reclaimed attic tiles (brick paving) sourced from a local market. Painted beamed ceilings, their whitewash carefully removed, are revived using reactive stains—revealing motifs from a bygone era. The paintings are illuminated indirectly, their subtle presence creating an inviting glow.

The attic, too, carries the traces of a sensitive intervention. The Czech architects preserved the original roof structure, supplementing it with above rafter insulation, ensuring the visibility of the beams inside. New timber elements are hand-hewn to match the historic structure where replacements were needed. The decking is installed precisely without mouldings, preserving the purity of the structure.

Despite the rigorous historic preservation, the spirit of the residential architecture is not entirely traditional. Modern technologies, including underfloor heating powered with a heat pump and recuperation, are complemented by a fireplace insert in the living room. The interior design, while nodding to the past, also expresses a contemporary flair. Exposed stonework is washed in grey hues, passages through thick load-bearing walls are lined with raw waxed steel and the ground floor is paved with dovetail-patterned tiles.

Details in the furniture design complete the project’s hybrid narrative. The dining room is anchored by a circular table engraved with coordinates marking significant moments for the owners. A dramatic chandelier suspended above the dining table illuminates the space. In the kitchen, the vaulted ceiling inspires the custom unit designed to follow the arches. A central island in solid wood with a stainless steel top is surrounded by cabinetry combining steel doors with built-in ventilation.

The success of Hradby Residence lies in its dialogue between eras. Medieval textures meet modern craftsmanship and every intervention is measured, designed to amplify what already existed. As the architects put it, “Enlightened clients, who approached the reconstruction very carefully and responsibly, were an essential ingredient of this realisation.” Together, they have ensured that a centuries-old guardhouse thrives as a home for contemporary life. For the OOOOX team that lives and works in restored historic spaces and sees housing as the foundation of wellbeing, the project reflects their larger philosophy: renovation as a practice of respect, where architecture remains as robust and steadfast as the lives it shelters.