London-based architecture practice DF_DC has completed a striking concrete-framed extension for a semi-detached home in Primrose Hill, featuring floor-to-ceiling glazing and a distinctive green roof. The project, known as T-House due to its chunky concrete frame design, represents the latest phase in a series of renovation works the studio has undertaken on the property.
The extension, measuring just 1.4 meters deep, serves as a compact yet impactful addition that expands the home's living and dining areas. Despite its shallow profile, the structure makes a bold architectural statement while preserving the majority of the existing garden space. The design team at DF_DC described the extension as a "tectonically autonomous piece" that sits above large expanses of glazing, creating dramatic framed views of the home's patio and garden.
The architectural challenge centered around balancing the need for additional living space with the preservation of the outdoor area. According to the studio, the brief required careful consideration of scale to retain as much garden space as possible, necessitating a design that was both compact in footprint and possessed landscape qualities. The garden itself had been an ongoing passion project for the homeowner over many years, featuring hard landscaping with planters and pots arranged around the perimeter for year-round use.
By projecting only 1.4 meters from the existing structure, the new space functions as a transitional threshold between the interior and garden, opening up oblique southern views. The concrete structure extends deeper into the home's interior, forming a central spine that houses integrated storage and seating areas. Sliding walls provide flexibility, allowing the snug area to be separated from the kitchen and dining space as needed.
Interior design elements showcase a sophisticated material palette that complements the raw concrete framework. Deep green fabric covers the low bench positioned between the two distinct areas and extends to a wall alongside the dining table. The central dividing wall features dark, textured veneer cladding, while overhead, the exposed concrete frame is paired with walnut ceilings specifically designed to match the dining table.
The concrete frame serves as more than just structural support, acting as the organizing element around which the kitchen, dining, and family snug areas revolve. The walls and partition elements incorporate substantial storage solutions in various configurations, with textile and tactile qualities achieved through the use of fabrics, textured veneers, and metal coatings that create visual and physical interest throughout the space.
The green roof topping the extension serves both aesthetic and environmental purposes, designed to be visible from multiple vantage points including views back toward the home from the garden and from the bedrooms located on the upper level. This feature reinforces the connection between the built environment and the natural landscape that was central to the project's design philosophy.
DF_DC was established in 2016 by Diego Calderon and Dario Franchini, operating offices in both London and Switzerland. The practice has built a reputation for thoughtful concrete architecture, with previous notable projects including a concrete apartment block overlooking Lake Lugano in Switzerland and a monolithic concrete home in Tegna that drew inspiration from Japanese architectural principles. Photography for the T-House project was captured by Lorenzo Zandri, documenting the seamless integration of the extension with both the existing home and its garden setting.
