20 Fenchurch Street

The façade access strategy for 20 Fenchurch Street, London—widely known for its distinctive curved form—required a highly customized building maintenance unit (BMU) solution to address both architectural and geometric complexity. The project incorporated three BMUs designed to park discreetly on the building’s curved roof, positioned between architectural fins to minimize visual impact when not in use. A primary challenge was enabling reliable BMU traversal across the roof, which slopes north–south by approximately ±20 degrees from the centerline and simultaneously curves east–west along the full length of travel. These compounded curvatures demanded precise engineering of track geometry, drive systems, and parking positions to ensure smooth and safe operation under all conditions.

The façade itself introduced additional complexity, featuring curved surfaces with both positive and negative slopes that required multiple access approaches. The BMUs were designed to service the façade using a combination of Independent Stabilization Anchors (ISA) and mullion guide systems, carefully coordinated to maintain consistent clearances and safe working distances. Early involvement of façade access specialists was critical to integrating the BMU tracks into the roof structure and architectural features without compromising aesthetics or performance. This project highlights how innovative BMU design and detailed façade access planning are essential for delivering safe, code-compliant, and visually sensitive maintenance solutions on architecturally expressive high-rise buildings.