The retrofit and extension of a Clerkenwell office in central London revitalizes a characterful five-story Victorian warehouse through a comprehensive, low-carbon transformation. The design preserves its industrial identity while achieving high environmental performance with an all-electric, fossil-fuel-free system.
Architecture for London completed the project with a meticulous fabric-first strategy, demonstrating how heritage buildings can meet contemporary sustainability standards through adaptive reuse, low-carbon materials, and durable construction.
Low-carbon strategies
The retrofit preserves the brick façades and timber floors while extending the structure by 50 percent, adding lightweight new levels without underpinning the original foundations.
A bespoke low-concrete blockwork core, developed with Forticrete and FORM Structural Design, reduces concrete volume by 25 percent. Its exposed masonry reinterprets a Flemish bond pattern, balancing structural efficiency and visual refinement without the need for additional finishes.
Energy and performance
The building operates entirely on electricity, with all gas systems removed. Roof-mounted photovoltaic panels supply renewable energy and mechanical ventilation with heat recovery retains internal warmth during air exchange.
An enhanced thermal envelope—featuring wood-fiber insulation on heritage façades, mineral wool for new cavity walls, and triple glazing by Bewiso—ensures airtightness and major energy savings.
Material efficiency
Materials played a central role in the design process. Lightweight additions were concentrated on the new stair and lift core to minimize structural intervention. Blockwork modules were precisely set out to reduce waste and mortar joints were calibrated to align new elements with existing floors.
The retention of original materials—including the brick facade and iron columns—combined with breathable insulation and demountable new components extends the building’s life by another 150 years.
By retaining the existing structure and minimizing concrete use, embodied carbon was substantially reduced. Lightweight extensions and the low-carbon core further cut material volume, while selective replacement avoided demolition waste. Reusing original components and minimizing new foundation work achieved significant life-cycle carbon savings compared to demolition and rebuild.
Adaptive reuse
Guided by circular economy principles, structural flexibility is built in through clear floor plates and pre-designed knock-out zones. Exposed blockwork and durable finishes ensure longevity and ease of repair.
Designed for disassembly, key components can be removed and recycled, avoiding single-use finishes. The demountable stair and lift core enhance adaptability, while the retained masonry expresses the building’s industrial character.
Precision detailing, thoughtful material selection, and a holistic energy strategy deliver A-rated efficiency and significant embodied carbon reductions, setting a benchmark for sustainable retrofit architecture.
Environmental design approach
The lightweight construction of the new floors, roof, and exterior walls allows the existing foundations, cast-iron columns, and masonry walls to carry additional loads without alteration.
The building's rear faces Albemarle Way, a narrow medieval lane, where façade details reference recessed brick panels and decorative lintels from nearby Victorian buildings. The street’s tight scale accentuates the visual depth of the articulated façade.
Overheating analysis refined the façade design, ensuring generous daylight while reducing glare and heat from the previously over-glazed south elevation. Zoned heating, low-energy LED lighting, and facilities for cycling promote efficiency and sustainable travel. Roof-mounted PV panels supply renewable power.
Removing 150 years of accumulated materials revealed the building’s inherent beauty—its brick piers, iron columns, and timber joists. Large sash and clerestory windows now flood these historic surfaces with natural light.
The property now houses six workspaces on the upper floors and a furniture showroom below, embodying durability, minimal waste, and long-term adaptability in line with circular economy and retrofit-first principles.
