A synthesis of sustainability and aesthetics

On the western outskirts of Cologne, a prestigious residential building has been built whose clear horizontal layout and cantilevered upper floor are stylistically reminiscent of Le Corbusier’s Villa Savoye. Designed with a focus on sustainability, the structure impresses with its understated architecture. Indoors, an open-plan layout combined with expansive glazed surfaces creates striking light accents. High-quality aluminium windows, doors and sliding doors from heroal ensure a harmonious interplay between the inside and the outside: the heroal W 72 window system, the heroal D 72 door system and the heroal S 77 SL lifting-sliding door system allow ample daylight to enter, connecting the interior spaces with the surrounding natural landscape.

Inspired by classical modern architecture, the building blends harmoniously into the new residential development in the west of Cologne, which is dominated by detached houses. Thanks to its well-considered combination of strategically placed openings and closed façade sections, it strikes a balance between transparency and privacy.

The architectural concept was developed by the architectural firm Benjamin von Pidoll Architektur in close cooperation with the clients. The fundamental design feature is the understated yet formally distinctive structure of the building: the monolithic upper floor of the three-storey building rests as a massive, static cube with large recesses atop a ground floor designed to convey a sense of lightness. This creates a deliberate, striking visual contrast between the two floors. The cantilevered level also creates accents with its slim outline and spacious integrated terrace. The building’s clear horizontal structure was inspired by Le Corbusier’s Villa Savoye in Poissy, which is a UNESCO World Heritage Site.

The planning and execution of the understated structure – as effortless as it appears – posed both architectural and technical challenges and took nearly three years to complete. In particular, the combination of a monolithic construction without external insulation and the cantilevered sections in the building shell made it necessary to use reinforced concrete columns in the walls for static reasons.

The transparent indoor design posed an additional challenge: “The staircase and the adjoining gallery form the central element and heart of the floor plan, with all rooms arranged around it. This creates zones of communication, diverse lines of sight and a special sense of openness”, explains architect Benjamin von Pidoll. “The view opens up through expansive windows on the ground and upper floors in the direction of the atrium and infinity pool and can be felt throughout the building. At the same time, the open-plan layout creates fascinating plays of light, with sunlight moving from the living area to the entrance hall over the course of the day”, continues von Pidoll.

Not only is the structure itself subtle, but so is the colour and material concept of the 12 x 14 m residence. The exterior walls are plastered in off-white, while aluminium louvres on the ground floor and between the window elements pick up the matt greige tone of the powder-coated aluminium windows. Calm, natural colours and materials also dominate the interior. “The entire building is a tribute to subtle shades of beige and grey, which create a restrained backdrop for a beautiful interior”, explains Benjamin von Pidoll.

With its high energy efficiency, the property – constructed in line with Germany’s KfW Efficiency House 50 standard – meets contemporary sustainability demands. The monolithic exterior wall creates the ideal conditions for an optimal indoor climate all year round. A resource-saving heat pump and a building automation system for the intelligent control of all building services ensure additional energy conservation. This concept is complemented by the use of high-quality heroal aluminium systems: the highly thermally insulated windows and doors (heroal W 72 and D 72) and the energy-efficient heroal S 77 SL lifting-sliding door system contribute greatly to the overall energy performance of the building.

“With its strong focus on sustainability, our architectural design reflects our client’s core credo and the defining principle of her fashion label, which specialises in sustainable clothing”, explains Benjamin von Pidoll. “Her work is grounded in the belief that a perfectly tailored garment made from high-quality, durable materials should accompany a person for many years. The same fundamental idea of timelessness and quality also underpins the architectural concept of this building.”

In keeping with the high standards of quality and durability, heroal aluminium systems were chosen for the windows, doors and lifting-sliding door systems. These not only impressed with their unique design variety, maximum flexibility and high performance, but also satisfied the client’s desire to use long-lasting, sustainable materials. Made from aluminium, heroal system solutions are particularly durable and low-maintenance. Thanks to its 100% recyclability, the material also contributes to the construction of sustainable buildings. heroal also offers all system solutions based on CO₂-reduced aluminium and post-consumer recycled aluminium. For this prestigious residential building, the elements were designed to match both the interior and exterior spaces: powder-coated in RAL 7006 m beige grey, they blend harmoniously into the overall design concept and create flowing transitions.

A total of 22 heroal W 72 window systems – some of them in the form of generously proportioned fixed glazing – ensure maximum transparency, high light transmittance and elegant design with their slimline face widths. The high-quality heroal hwr powder coating further emphasises the aesthetic value. Another detail reflecting heroal’s consistent system-based approach: colour-matched window sill systems from heroal, which enable architects and fabricators to realise coordinated overall design concepts. From a technical point of view, the heroal W 72 system impresses with its sophisticated web geometry and fully foam-filled insulation zone: with a design depth of 72 mm in the frame and 84 mm in the casement, heroal W 72 achieves U_w values that meet the highest thermal insulation requirements for windows. This makes a tangible contribution to the building’s energy efficiency and helps reduce operating costs in the long term.

The deliberate placement of the expansive fixed glazing and two heroal S 77 SL lifting-sliding systems, each 3 m high, emphasises the openness and spaciousness of the house, while inviting exciting light accents indoors. The slimline profiles of the elements maximise the amount of light entering the room, open up wide lines of sight and create flowing transitions between the indoor and outdoor spaces – transitions that are further emphasised by the barrier-free ground threshold when the casement is open. The design of the sliding doors blends in seamlessly with the overall appearance. Their functionality is equally impressive: distinguished by their exceptionally smooth operation, even large-format units open and close effortlessly after years of use. heroal lifting-sliding door systems offer a perfect combination of transparency, stability and heat insulation, even over large surfaces.

To protect against direct solar radiation and overheating on hot days, the window and lifting-sliding systems were equipped with shading – in part using external venetian blinds, and in part using roller shutters. These ensure a pleasant indoor climate, reduce the need for cooling and support the building’s overall sustainability strategy. For the integration of sun protection on the floor-to-ceiling elements, heroal’s Project Sales team provided consultation and support to the executing window fabricator, Kapp.

The heroal entrance door was also finished with an hwr powder coating in RAL 7006 m, visually matching the windows and lifting-sliding systems. The heroal D 72 door system blends harmoniously into the overall ensemble and impresses with its profile depths identical to those of the window systems, allowing for a consistent and aesthetically pleasing appearance. Beyond the aesthetic advantages of its design, the system also scores highly in terms of functionality: thanks to its modular system design and various insulation variants, the door system can be flexibly adapted to meet a project’s insulation requirements – and, with its top performance values, enhances both the energy efficiency and the overall value of a building.