BLAF architecten’s JTB house employs a novel method of building insulation

From a distance, the JTB residence, in Oud-Heverlee, Belgium, by BLAF architecten appears to emerge from an undulating landscape, with battens—shaped by bricks—structured to support and give form to the residential building. The structure's facade is the result of attempts made by the architects to replace cavity walls used conventionally, with a structural system that demands lesser insulation. In this process, the architects have managed to give form to a unique design—a vestibular semi-shaded space that enhances the appearance of the facade, while also enabling the provision of a full glass wall cradled within these offcuts. Ensuring both, a glimpse of the indoor walls and reflections from the outdoors, and spanning views of the vicinity from within the structure, BLAF architecten has managed to integrate fenestrations on an entire wall of the facade, while ensuring the passive dissemination of heat and light into the building.

Sharing their insights on the configuration of the facade, the architecture studio from Lokeren, Belgium, shares, "The underlying landscape is south, so the living spaces not only open up to the landscape, but allow a lot of passive solar gains. The wooden curtain wall retreats to the south in relation to the brick wall, creating a three-storey high canopy that offers protection against too much sun, but also against rain. The volume fits so well into its context, but its hexagonal shape and its verticality create a sculptural volume that can actually stand anywhere.”

While the outer brick wall is a free standing structure that only carries itself, the wooden wall is a light structure that carries the loads of all the floors and the roof. “We first build an outer wall, and then a light timber frame inside, or vice versa. The concrete (ring) beams in the facade guarantee the stability of the self-supporting facade masonry under wind loads. You can also break down the outer shell or the inner shell, because they each stand on their own,” share BLAF architecten in an official release.

The architects adopted the regional usage of bricks in the construction of the residence. They also ensured that the materials employed to build both the structure and the interior spaces were acquired locally. The usage of brick and wood in place of concrete and steel not only gives it an earthy look evocative of large-scale brick architecture more common in the last few centuries, but also guarantees the application of bio-based insulation—such as lime hemp—with ease. “The brick wall and wooden construction are build in a way that is easy to apply more insulation. In traditional cavity wall systems, it is not easy to insulate a lot. Hence, this system is not future proof anymore. So, we researched on and about other hybrid ways to reach this result, and came to this easy way to build in a more sustainable manner,” the studio shares.

Another unique method of construction and structuring that ensures less wastage of materials is the technique of interlocking bricks on the edges, such that the requirement of brick bats nullifies. This ensures both a reduction in the labour and time employed to position the bricks, and the resultant brick waste from the construction. In addition to the pragmatic benefits of positioning bricks in this manner, the patterned concatenation that emerges from this arrangement, as well as the play of light and shadow in the brick crevices makes for a unique defining feature in the residential architecture.

The architects of JTB created the residential design for a single family. They approached the site with a respect for the undulating relief in the vicinity and the contextual environment—with the aim of building a compact space, so as to facilitate an easy visual relationship from both within and without the structure. “In order to integrate the volume discreetly into the landscape and to provide a sufficient residential program, the house is pushed into the slope. Due to the compact hexagonal, equilateral footprint, the volume stands solitary in the landscape, the undeveloped land retains its relief as much as possible. The shape with its sloping sides creates a greater distance to the lateral plot boundaries, which limits the impact on the environment and provides privacy to the neighbours,” the architects explain. The privacy of the neighbours is further ensured by limiting the windows on the side walls.

In keeping with the demands of the client, who is a pianist, BLAF architecten also added a music room within the structure that is accessible to the public. While the front of the building is split vertically across two floors, the rear of the structure has three floors. The front side, facing the street, encapsulates closed functions such as storage rooms, sanitary facilities and more, on each of the floors. On the other hand, the rear end, with spanning views to the landscape, comprises the living area on the street level, the workspace and music room on the lower level and the bedroom on the upper floor. "The curtain wall guarantees a view of the landscape behind on every floor. The openings in the brick volume frame the landscape," the studio shares.

Project Details

Name: JTB House
Location: Blanden, Belgium
Year of completion: 2022
Architect: BLAF architecten
Program: Single-family house
Stability + EPB: Heron Engineers
Structural Work: Legoclean
Timber Frame: Peter Willem
Plumbing + Heating + Ventilation: Enerpro
Techniques: Exie
Lime Hemp + Clay Plaster: Ecobouw Craeghs
Stairs: Stiel Atelier
Landscape Architecture: Buls Claes