Hackney has one of London’s densest concentrations of Victorian terrace housing — the majority built between 1870 and 1910 from solid London stock brick. These properties have original DPCs now 115–150 years old, most of which are either failing or have been bridged by later alterations such as tiled front steps, raised courtyard levels, or cement skirtings applied during 1970s refurbishments.

The widespread conversion of Hackney terraces into flats — particularly common in E8 and N16 — adds another layer of complexity. Each conversion reduces natural ventilation and creates new moisture pathways: cold party walls, inadequate bathroom extraction, and new bathroom pods added without adequate tanking.

Council-built estates in Homerton (E9) and Clapton (E5) frequently suffer from different problems: flat-roof failure, inadequate cavity tray installation in precast concrete panels, and persistent condensation in properties where original windows have been replaced with sealed double glazing without compensating ventilation.