Talking Conservation

What’s the biggest threat to your historic building? Water.

In this special episode of Talking Conservation, we’re joined by Steve Hogarth — SPAB Fellow, heritage mason, and rope access conservator with Highlife Rope Access — to explore how the smallest details up high can make the biggest difference to your building’s long-term health.

We dig into:

- Why effective drip detailing is critical to keeping water off your building

- What causes damage when high-level details are missing or poorly repaired

- Sky-facing joints and how they differ from vertical surfaces

- How to assess and choose the right lime mortar mix for exposed locations

- The overlooked genius of traditional detailing (like string courses, throatings & hood moulds)

- When to use NHL, hot lime, or natural cements- Why small targeted maintenance can prevent costly full-scale repairs

- Real-world insight from Steve’s rope access conservation work on churches and historic buildings

This is an essential listen for homeowners, tradespeople, or professionals working with older or listed buildings.

Chapters:

00:00 Introduction

01:57 Drips and throatings

06:44 Impact of the Grand Tour

07:35 Umbrellas for buildings!

09:13 Clogged details and past rebuilding

10:28 Water pathways and identifying problems

12:59 Stephen's anecdote about finding a leak

15:01 Stopping water getting in

16:54 Junctions between materials

17:38 Choice of material for repair

19:56 Mortar mixes for exposed areas

24:38 Dealing with coastal locations

27:21 Ongoing maintenance

29:04 Limewashing or covering and changing exposed elevations

31:08 Shedding and sky-facing surfaces

35:02 Concluding comments

35:54 Outro

👉 High Life Rope Access: https://www.highliferopeaccess.com/

👉 Need expert 1:1 advice for your traditional or historic home?Book a video consultation with an independent specialist at www.expertible.com

🎓 Professionals wanting mentoring or training with Stephen Boniface? Visit www.beconservation.com

🔔 Subscribe for more episodes on lime, building conservation, materials, and expert insights from tradespeople working at the sharp end.

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 CO₂

Ep.2: Lime Mortar Types Explained – Key differences between air lime, NHL, pozzolans & more

Ep.3 Part.1: Which Lime to Use? – Mortars for pointing & bedding in older buildings

Ep.3 Part 2: Which Lime to Use? - Plasters and Renders

Ep.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 #historictimberframes

Chapters00:00:00 – 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

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

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

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

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 works

How pozzolans change lime chemistry and performance

What makes a lime hydraulic and how NHLs are classified

The role of hybrid mixes, including hot lime and insulating lime plasters

The importance of matching materials to traditional buildings

This 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

Rich finds a lime kiln. Stephen nerds out on chemistry. Somehow, it all makes sense.

In this episode of Talking Conservation, we walk through the full lime cycle — from burnt limestone to breathable lime mortar — and explain why it still matters today.

Packed with practical knowledge, dry humour, and the occasional chemistry flashback, this is your crash course in the building material that’s been quietly doing the heavy lifting for centuries.

Rich comes across an old disused lime kiln and this leads us to discuss the Lime Cycle. Stephen talks about how a source of Calcium Carbonate (e.g. Limestone) is taken through various processes that each change the nature of the material, but that at the end it reverts to a form of Calcium Carbonate again - hence the term Lime Cycle. Rich reflects on this at the end and mentions that we will look at various forms of lime (as used in building works) in a future video.

#limestone #thelimecycle #buildinglimes #buildingconservation #talkingconservation #buildingmaterials

Douglas Kent is the Technical Secretary ofSPAB, but in his private capacity purchased The Old Sun Inn, Saffron Walden, afew years ago, having previously acquired the neighbouring properties. We talkabout how Douglas got involved in conservation and how he came to the point ofbuying these buildings.  We discuss thechallenges he has so far faced and those he is yet to tackle. Amongst theissues discuss3ed we consider how to undertake appropriate repairs, dealingwith inappropriate past works, upgrading to modern requirements and dealingwith building regulations.  Douglas tellsus about his plans for the future and mentions some of the events lined up.

The website of The Old Sun Inn can be foundhere:

https://oldsuninn.com/

Instagram: https://www.instagram.com/oldsuninn/

Facebook: https://www.facebook.com/profile.php?id=100093592571779

Alec Clifton Taylor’s ‘Six More English Towns– Saffron Walden’ – the quality of the video is not great.

https://www.youtube.com/watch?v=KgUyzk8V7IY

Links to books on Amazon.  Please note that we do earn a very smallamount of commission from Amazon if you purchase through these links.

Alec Clifton Taylor

Six More English Towns (book) https://amzn.to/3FDgTOI

The Pattern of English Building https://amzn.to/3DyIPmc

Ronald Brunskill

Illustrated Handbook of VernacularArchitecture https://amzn.to/3FydvnX

Chapters

00:00:00                        Intro.

00:08:21                        Welcome to The Old SunInn and introduction of Douglas.

00:40:03                        Douglas’ background andbecoming a surveyor.

02:33:15                        Introduction to SPAB andgetting a job there.

03:39:06                        How Douglas came topurchase the properties.

05:45:11                        History of thebuildings.

08:21:09                        Condition at the time ofpurchase.

09:12:06                        Original intentions forthe buildings.

11:21:00                        Tackling externalproblems.

14:06:17                        Dealing with the layersof limewash, plasterwork, and pargeting.

20:53:16                        History of thepargeting.

24:57:23                        Obtaining consent forworks.

27:06:22                        Being a leaseholder.

29:08:11                        Advice to those puttingin consent applications.

31:33:07                        Surprises encountered.

35:03:05                        Understanding thebuilding – why it is important.

35:49:14                        Challenges of modernliving and requirements, particularly services.

38:18:03                        Building regulationsincluding fire safety.

40:20:10                        Windows and thermalperformance.

44:14:13                        When to DIY and when notto.

46:04:04                        The need forprofessionals to have practical knowledge.

47:42:16                        Favourite books.

49:34:21                        Favourite building.

50:23:12                        Contact information andfuture events at The Old Sun Inn.

52:51:02                        Outro.

Ian is the CEO of Stow Maries Great War Aerodrome (museum). We talk about his past and how he came to be at Stow Maries, as well as describing the site and its buildings. Some issues we specifically talk about are Hoop Iron and Asbestos. We also discuss the use of volunteers and how these are essential to the running of the museum. An ongoing problem that faces most museums is funding and we talk about funding for Stow Maries. We also look at future plans and Ian also tells us what inspires him.Chapters00:00:00 Music intro. 00:07:09 General introduction.00:30:07 Introduction to the museum and Ian Flint.00:56:11 Ian’s story about how he became involved.02:54:08 About Stow Maries Great War Museum.04:28:23 About the site.08:34:15 Types of buildings on site.10:01:03 Accessibility, facilities, and buildings in use.12:00:13 The present condition of buildings and what works are ongoing and planned.14:14:15 Hoop Iron – what is it and how it is being dealt with?19:21:06 The airfield aspect.20:22:19 Asbestos – how it is approached and dealt with.23:33:04 Seeking professional guidance.26:35:21 Dealing with contractors.30:36:18 Volunteers – creating a group of volunteers and retaining them.38:29:04 Funding and the Heritage Lottery Fund.44:22:00 Donating to the museum.45:16:23 Social media presence.46:24:02 The future of Stow Maries.49:10:03 What inspired Ian and continues to drive him.52:18:19 Favourite place or places.55:14:04 Closing comments and thanks.55:29:09 Outro.

Buildings Insurance for Historic Homes: Everything You Need to Know