Cast iron pipe was the dominant material for soil stacks and external drainage in UK construction from the mid-19th century until the 1970s, and remains widely visible on Victorian and Edwardian properties across London. The pipe offers excellent fire resistance, low noise transmission and high mechanical strength, making it a preferred specification for modern flats and tall residential buildings under BS EN 877. Cast iron is identifiable by its grey or painted black exterior, heavy spigot-and-socket joints and characteristic ringing sound when tapped. Older installations used lead and yarn for jointing, while modern systems use mechanical coupling sleeves. Common defects include external corrosion at the base of stacks, cracked sockets from impact damage and internal scale build-up. Replacement is generally considered only where the pipe has collapsed or is no longer structurally sound.
Cast iron pipe (drainage)
Heavy ferrous drainage pipe traditional in Victorian London, valued for fire and acoustic performance.
