This episode explores the history, function, and practical impact of mortars and renders in traditional and modern construction. We examine how lime mortar, with its breathability and flexibility, became a cornerstone of historical building techniques, and why it's still vital in conservation today. We break down the key differences between non-hydraulic and hydraulic lime, cement mortars, and hybrid mixes, focusing on their performance, compatibility, and risks. We also explore traditional and modern render types-from Georgian lime renders to pebbledash and silicone systems-and their role in protecting and expressing a building's character. Real-world surveying insights show how incorrect repairs, like cement overlays on lime joints, can damage historic brickwork and what to look out for in the field. We close with a look at modern mortar additives, explaining when they work, where they fall short, and why understanding context is essential for getting it right. A must-listen for surveyors, builders, and anyone passionate about the materials that hold buildings together.