Which Lime Mortar to Use? Part 3 – Floors, Chimneys & Exposures Areas

Not sure which lime to use for a chimney, solid floor, or coping stone? In this episode of Talking Conservation, we explain how to choose and apply the right lime mix for floor construction and high-exposure areas in older homes. In this episode, Rich and Stephen continue their deep dive into lime mortars, exploring how to apply them in real-world contexts where performance under pressure really matters. We cover the use of limecrete floors and lime ash floors, debunking common myths about moisture performance and clarifying where lime-based solid floors offer real benefits (and where they don’t). We also examine high-exposure areas such as chimneys, ridge tiles, parapets, and copings — where material choice is critical. Should you use NHL 3.5? NHL 5? Is cement ever appropriate? We walk through the options and trade-offs. Whether you're repairing flaunchings or considering a breathable solid floor alternative, this episode gives you practical advice grounded in conservation principles. 👉 Missed the earlier episodes? Start here: • Ep.1: The Lime Cycle Explained – Where lime comes from, how it’s made, and how it changes chemically from limestone to lime and back again. • Ep.2: Lime Mortar Types Explained – Air lime, NHL, hot lime, and pozzolans demystified — we explain their properties and behaviour. • Ep.3: Which Lime to Use? Part 1 – Mortars for Building & Pointing Older Buildings – Where and how to use the different lime types for masonry and repointing. • Ep.4: Which Lime to Use? Part 2 – Plasters & Renders - Which types of plasters to use internally and pros and cons of the various options for external renders. 👉 Subscribe to our channel for future episodes on conservation, traditional buildings, and expert insight. 👉 Need personalised advice? Book a consultation at www.expertible.com 👉 Professionals can also book mentoring or training via Stephen’s site: www.beconservation.com