What Lies Beneath? Understanding Substrates in Older Buildings – Lime Series Bonus Episode
Before choosing your lime mortar or plaster, you need to understand your substrate.In this bonus episode of Talking Conservation, Stephen and Rich explore the importance of knowing what's behind or beneath your mortar; from soft handmade bricks and old stone to chalk walls and cob. Whether you're repointing, plastering, or rendering, understanding the substrate is critical to choosing the right mix and achieving long-lasting results.We cover: - What a “substrate” actually means in traditional buildings- Common types found in historic homes (brick, stone, cob, timber) - How substrate affects your lime choice and application- Assessing problems and indicators of hidden issues - Mistakes to avoid when applying lime to inappropriate surfaces - Decision making, such as when to strip inappropriate materials - Key questions to ask before starting any conservation work When to call in the professionals - Keeping a record▶️ Whether you're a homeowner or a professional working with heritage buildings, this video helps you avoid common issues and build with confidence.👉 New to the Lime Series? Start here:Ep.1: The Lime Cycle Explained – How lime is made and reabsorbs CO₂Ep.2: Lime Mortar Types Explained – Key differences between air lime, NHL, pozzolans & moreEp.3 Part.1: Which Lime to Use? – Mortars for pointing & bedding in older buildingsEp.3 Part 2: Which Lime to Use? - Plasters and RendersEp.3 Part.3: High Exposure Areas & Floors – Using lime in chimneys, ridges, parapets, and floors🔔 Subscribe for upcoming episodes on more specialist areas 📞 For 1-to-1 advice or a consultation, visit: www.expertible.com💼 Professionals: Training & mentoring available at www.beconservation.com#TalkingConservation #SubstratesExplained #LimeMortar #BuildingConservation #OldHouseDIY #HistoricHomes #TraditionalMaterials #LimePlaster #problemsolving #decisionmaking #professional help #heritageskills #limerender #lathandplaster #historictimberframesChapters00:00:00 – 00:00:50 Introduction00:00:50 - 00:02:23 What is a substrate?00:02:23 - 00:03:33 Flint00:03:33 - 00:05:22 Stone00:05:22 - 00:05:31 Cob and earth00:05:31 - 00:06:12 Wattle and Daub, lath and plaster00:06:12 - 00:06:56 Multiple substrates00:06:56 - 00:08:24 Behaviour of substrates (the science bit!)00:08:24 - 00:09:43 Timber00:09:43 - 00:10:57 Absorbency and moisture performance00:10:57 - 00:14:25 Cement render on timber frame (case study)00:14:25 - 00:16:34 Assessing problems and key indicators00:16:34 – 00:19:48 Delamination and hammer testing00:19:48 – 00:23:02 Decision making00:23:02 – 00:24:43 Should I remove cement render/pointing?00:24:43 – 00:26:36 Have I got layers of material?00:26:36 – 00:27:46 A judgement call and bringing in professionals00:27:46 – 00:28:52 Substrate preparation00:28:52 - 00:30:43 Wetting down surfaces 00:30:43 – 00:32:05 Plaster coats00:32:05 – 00:34:56 Use of hair in mixes00:34:56 – 00:39:25 Controlling the ‘set’00:39:25 – 00:40:14 Lath and plaster00:40:14 – 00:41:33 Dealing with modern interventions00:41:33 – 00:46:37 Removing modern material00:46:37 – 00:49:30 Surface finishes00:49:30 – 00:55:58 Changing aesthetics and appearance00:55:58 – 00:56:56 Key message – understand the building00:56:56 – 00:58:27 The importance of keeping a record00:58:27 – 00:59:11 Future episodes00:59:11 – 00:59:48 Expertible00:59:48 – 01:00:05 Close01:00:05 – 01:00:28 Outro
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Which Lime to Use? Part 3 – Floors, Chimneys & High-Exposure 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#BuildingConservation #TraditionalMaterials #LimeMortar #HistoricBuildings #Retrofitting #HeritageSkills #TalkingConservation #Architects #Surveyors #Builders #ConservationProfessionals
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Which Lime to Use? Part 2 – Plasters & Renders for Older Buildings
Lime Plaster & Render Uses Explained — How to choose the right mix for old buildingsIn this episode of Talking Conservation, Stephen and Rich continue their deep dive into lime applications; this time focusing on internal plasters and external renders for traditional and historic buildings.We discuss the different types of lime used in plaster and render work; including air lime, NHL 2, NHL 3.5, hot lime, and pozzolanic mixes and how to choose the right one based on the substrate, exposure, and performance needs.We cover:Why flexibility and vapour movement matter in internal plaster systemsWhen to avoid overly hard or dense mixes on older wallsHow to approach external render repairs or replacementsWhat to do when cement-based render is already presentModern vs. traditional techniques — and where specialist mixes like insulating plasters might helpThis practical discussion is rooted in conservation knowledge, with decades of experience in what works, and what doesn’t, when applying lime-based systems in heritage settings.Whether you're working on your own older property or advising clients as a professional, this episode will help you make informed choices on plaster and render mixes.👉 Missed Part 1? Watch it here: “Which Lime to Use? Part 1 – Mortars for Building & Pointing Older Buildings”👉 New to the series? Start here:• Ep.1: The Lime Cycle Explained — where lime comes from, how it's made, and how it behaves chemically in use• Ep.2: Lime Mortar Types Explained — covering air lime, hydraulic lime, hot lime and hybrid mixes👉 Subscribe for more on building conservation, restoration, and heritage homes👉 Homeowner? Book a 1-1 consultation at www.expertible.com👉 Professional? Learn more about mentoring or training with Stephen at www.beconservation.com
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Which Lime to Use? Part 1 – Mortars for Building & Pointing Older Buildings
Lime Mortar Uses Explained — How to apply the correct mix for your historic homeIn this episode of Talking Conservation, Stephen and Rich explain how different types of lime mortar are applied to traditional buildings; from soft brick pointing to bedding stone walls. We cover the pros and cons of air lime, NHL 2, NHL 3.5, and hot lime mixes and how they compare to cement-based mortars often found in repairs.When considering pointing; we talk about the adage that "the pointing should always be softer than the surrounding masonry" and explain this. We discuss when to consider repointing and briefly look at what repointing involves. In our discussion we briefly touch on tuck pointing.During the discussion we consider how brick making has changed over the centuries and how mortar/pointing has also changed.Whether you’re a homeowner working on an older property or a trade professional unsure which lime mix is right for the job, this episode gives you practical guidance rooted in conservation experience.The next episode looks at the use of lime for internal plasters and external renders.👉 New to the series? Watch these first:• Ep.1: The Lime Cycle Explained — where lime comes from, how it's processed, and how it transforms chemically from limestone to lime and back again.• Ep.2: Lime Mortar Types Explained — the different types of lime (air lime, NHL, hot lime, pozzolanic mixes), their characteristics, and how they behave in buildings.👉 Subscribe to our channel for future episodes on building conservation, heritage homes, and expert advice.👉 Book a consultation with us for 1-1 advice on managing your historic home on www.expertible.com👉 Professionals involved in working on or with historic, traditional, or listed buildings may want 1-2-1 mentoring and/or training with Stephen. Visit his website at www.beconservation.com
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Lime Mortar Types Explained; Essential knowledge for older buildings
In this episode of Talking Conservation, we explain the different types of lime used in building and restoration work. If you have ever wondered what the difference is between air lime, natural hydraulic lime (NHL), pozzolans, or hybrid lime mixes, this video will give you a clear introduction.Understanding the types of lime is essential before starting any work on older or historic buildings. Whether you are a homeowner, builder, surveyor or anyone dealing with traditional construction, choosing the right lime can make a big difference to the long-term condition of the building.We cover: What air lime is and how it worksHow pozzolans change lime chemistry and performanceWhat makes a lime hydraulic and how NHLs are classifiedThe role of hybrid mixes, including hot lime and insulating lime plastersThe importance of matching materials to traditional buildingsThis is the second video in our lime series. In the next episode, we will discuss how to select and apply the correct lime type for specific jobs including pointing, rendering, plastering and flooring.👉 Subscribe to our channel for future episodes on building conservation, heritage homes, and expert advice.👉 Book a consultation with us for 1-1 advice on managing your historic home on www.expertible.com👉 Professionals involved in working on or with historic, traditional, or listed buildings may want 1-2-1 mentoring and/or training with Stephen. Visit his website at www.beconservation.com
Welcome to Talking Conservation, where we talk about all things related to our built heritage. Whether you own an historic building, are responsible for a heritage site, or are a professional consultant, contractor, or simply interested - this is the place to find out more.We discuss various matters and conduct interviews with a wide range of people involved with our heritage in some way. This includes architects, surveyors, archaeologists, conservation officers, contractors, conservators, historians ... the list goes on.We are interested in and talk about any aspect of heritage; not only listed buildings, but all older and traditionally constructed buildings and anything that could be considered a heritage site.Stephen's Heritage Conservation Community information can be found here: https://beconservation.com/heritage-conservation-communityRich's platform putting owners in touch with consultants can be found here: https://expertible.com/
Ireland