This episode explores bitumen and asphalt, two essential materials used in roofing, damp-proofing, and tanking. We trace their geological origins, historical use in ancient and modern construction, and their roles in UK housing. We explain how they’re used in flat roofs, DPCs, and basements, highlight common defects, and look at modern alternatives and sustainability issues. A must-listen for surveyors seeking to better understand these often overlooked but critical waterproofing materials.