Welcome to Where it's AT | the Architectural Technology Podcast

In this episode of 'Where it's AT' from CIAT, host Chris Halligan, a Chartered Architectural Technologist, is joined by Ian Pritchett, Innovation Director at Green Core Homes, to discuss the use of hemp in construction. They explore the historical context of hemp as a sustainable material, its benefits, the challenges of commercial application, and the development of prefabricated hempcrete panels. Ian shares insights on the material's thermal properties, breathability, and its potential to last for centuries as long as appropriate maintenance is performed. The episode also touches upon the commercial hurdles and insurance issues faced while trying to mainstream hemp-based construction.

Chris Halligan MCIAT, CEnv

Chartered Architectural Technologist (MCIAT) and Chartered Environmentalist (CEnv), with a career spanning over three decades, Chris has been involved with a wide range of architectural projects. This experience covers leading teams from inception to completion across a variety of sectors including residential, educational, commercial, leisure and institutional spheres. As well as being adept at the technical and functional resolution of buildings, Chris also specialises in Sustainable Design with a particular interest in the use and performance of building materials in respect to the environment. In this capacity he is an accomplished public speaker, presenter, guest lecturer, and advisor.

Ian Pritchett BSc(hons)

A physics graduate from Durham University. From 1987 to 2007 Ian was Managing Director of IJP Building Conservation Ltd, one of the leading conservation contractors in the UK. IJP specialise in the repair of all kinds of historic buildings including windmills and water mills. 2002 to 2013. Ian’s growing awareness of environmental issues and belief that traditional materials have an important role in the future of mainstream construction lead to the formation of Lime Technology Ltd. (in 2002), a company dedicated to pushing the use of traditional lime mortars into the new build market, as an ecological alternative to cement, by the innovative use of modern methods. 2013 to date. In 2013 Ian left Lime Technology and set up Greencore Construction Ltd, now rebranded as Greencore Homes Ltd. Ian is currently Innovation Director. Greencore is pioneering low and zero-carbon houses using its own Biond building system. This is a closed panel timber frame system insulated with Lime-Hemp and natural fibre insulation. In January 2022 M&G became a shareholder and Greencore plans to build 10,000 “better than zero-carbon” homes by 2035.

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00:00 Introduction

00:35 Meet the Hosts: Chris Halligan MCIAT and Ian Pritchett

01:03 The History and Revival of Hemp in Construction

02:18 Modern Applications and Challenges of Hempcrete

07:04 Prefabrication: The Future of Hempcrete Construction

09:35 Sourcing and Material Composition

11:38 Thermal and Environmental Benefits of Hemp

18:34 Commercial vs. Residential Use of Hempcrete

20:43 Regulatory and Financial Hurdles

24:19 Sustainability and Longevity of Hempcrete Buildings

28:31 End of Life and Recyclability of Hemp Panels

29:34 Conclusion and Final Thoughts

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Prefabrication solved hempcrete's commercial viability challenges

The shift from wet, on-site casting to factory-prefabricated panels was the breakthrough that made hempcrete practical for commercial construction. This eliminated weather-related delays and reduced production time from weeks to just 48 hours per panel, making it viable for projects with strict timelines and penalties.

Hempcrete offers superior thermal performance through phase change properties

The material's unique cellular structure allows moisture within the hemp to change between liquid and vapor states, absorbing and releasing energy. This creates a natural phase change effect that makes real-world thermal performance about twice as good as predicted models, while providing thermal inertia without traditional thermal mass.

Sustainability without compromise or premium costs

Hempcrete construction delivers better, healthier, more comfortable homes that use less energy and don't cost more to build than conventional methods. The material is fully recyclable (can be spread back on agricultural land), buildings last for centuries with proper maintenance, and the entire supply chain can be UK-based, making it a genuinely sustainable solution that doesn't require sacrificing quality or affordability.

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Learn more about Greencore Homes

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Know someone who could benefit from listening? Subscribe and share this episode with your network.

Know someone with a story to tell or a topic to explore? Email us at atpodcast@ciat.global to nominate a guest or a topic.

Want to learn more about Architectural Technology, how to progress your career, or how to work with a Chartered AT? Head to architecturaltechnology.com to find out more

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Podcast recorded and edited by: Jon Clayton [Podcasting]

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Disclaimer

The contents and views expressed by individuals in the Where it's AT podcast are their own, and do not necessarily represent the views of the companies they work for or the Host. This podcast is for informational purposes only and should not be considered as advice.

It's always seemed mad to me that, people designed for

60 years because in the life of a residential house, it, it normally

goes on for hundreds of years.

It's no different with, a panelised hempcrete house.

It will go on for centuries as long as certain things are done.

Welcome to Where it's AT.

The podcast from CIAT shining a spotlight on the future focused design

discipline of Architectural Technology.

Know someone who could benefit from listening.

Subscribe and share this episode with your network.

Chris Halligan MCIAT: Hello again.

Thank you for joining us today on, uh, where it's at.

I'm Chris Halligan, Chartered Architectural Technologist and

Chartered Environmentalist, currently chair of CIAT's Climate Society.

Check out my bio in the show notes for more info if you really want.

Very lucky to have a guest today as co-host of Ian Pritchett, who's the

innovation Director at Green Core Homes.

Welcome Ian.

Thank you, Chris.

Good to be here.

Chris Halligan MCIAT: And today we're gonna be talking about hemp.

I've got a longstanding interest in sustainable materials, uh, and the

effects of building materials on the, on the environment, and, um.

I've been interested in hemp for many decades.

It's a fascinating organic.

Material.

And it's often touted as being one of the most sustainable or renewable.

Now, one of the things that really have to bear in mind when we

talk about sustainability is that the only truly things that only

things that are truly sustainable are things that we can replace.

And that brings us back all the time into organic materials, things that can

be grown and hemp cells in that aspect.

It's been around.

Commercially for anything up to 10,000 years.

The first paper was created in China in a hundred BC from hemp.

Most of the British empire was won in hemp based clothing.

And in recent decades, it's undergone something of a

revival with the odd hiccup.

I first encountered him probably.

Nearly 20 years ago when hemp was first being used as a spray material.

But things have moved on a bit there.

And fortunately, Ian, who was with Green Core Homes knows more

than I will ever do about hemp.

Perhaps you'd like to give us a quick overview of, um, how hemp

came to be reused in the building industry in modern times, Ian.

Yeah.

Thanks.

Thanks Chris.

It sounds as if you know an awful lot about hemp as well, so hemp.

Really has been used in construction to my knowledge for about three or

400 years in, in central Europe.

And it's been used mixed with clay or lime to, to create a, a rigid installation

material that was often used with a timber frame in places like Austria

and Germany and, uh, central Europe.

About 30 or 40 years ago, the.

The French really started taking this forward, and they started developing new

line based binders that could be mixed with hemp to create thick walls that were

more like cob than the the wattle and DOB format of going between a timber frame.

And I first came across it about 25 years ago when, uh, an

architect called Ralph Carpenter.

Was using it in Suffolk and I went to a few talks that Ralph was doing

and was very inspired by his work.

And at that time, my background was in the repair of historic buildings,

so this was, uh, very close to the sort of materials I was used to using

in, in his historic building repair.

And.

I liked the look of the material.

It had a great feel about it.

It had a great story and I got to know Ralph a bit better and we started working

together and then doing some research with Bath University to see how we could

really optimize the use of the material and, and the rest is history really.

I've been hooked for the last 25 years.

Chris Halligan MCIAT: So I do recall at that time the, the main way of use use

of hemp was in the form of hempcrete.

And it seemed to be used in, uh, residential developments in a spray

application onto a timber frame.

But I do believe that led to some problems with regard to the climate.

Is that right?

Well, when I first came across it, it was actually being used

as a, a shuttered and cast material.

So it was based around a timber frame with shuttering spaced away

from the timber frame, and then the material was mixed and poured into the

shuttering and likely tamped into place.

As ever with building materials.

People want to try and make it as fast and efficient as they possibly can, and

there were a lot of people in France who were experimenting with mixing it

and then putting it through some sort of spray machine to spray it against walls.

And they were doing that mainly because they were lining the inside of stone

farmhouses in Normandy and Brittany.

But the technology allowed construction to be much faster.

It.

Theoretically meant you didn't need the shuttering if you could spray it in place.

It's always been challenging to find methods of spraying it without the, the

hemp itself clogging up the machine.

Uh, the hemp often contains fiber, and fiber tends to wrap itself

around the moving parts of machines.

So, so it was quite difficult and some of the people, particularly in France,

came up with some great ways of doing it.

But the problem wasn't so much around.

The fact that it was being sprayed, the problem was around the fact that it was a

wet material being used on site and once.

Hemp or hempcrete was dry.

It was the most amazing material.

Getting it dry could sometimes be a bit of a challenge if the

weather wasn't on your side.

So it lent itself very well to one-off self-build type projects.

You know, the sort of things we all see on grand designs where somebody sets out.

Thinking it's going to take six months and it takes a year to build their house,

and everybody's still happy at the end.

But when you try and translate that to the commercial world where you are

trying to finish houses in sensible periods of time, and you are entering

into contracts with time penalties involved with them it really led to

some challenges over the winter and, uh, led us to look at new ways of using it.

Chris Halligan MCIAT: Yeah, that's fascinating because you, you must have

found some of the same issues that we were looking at, at, at the time.

Um, roundabout 2005, 2010.

We were looking at.

Sustainable.

It's what we consider to be sustainable materials for use on a commercial basis.

But we found that most of the, the knowledge and the use was done almost

on what a say was an enthusiast level.

That is, it's one-offs, uh, self builders and it's great.

And, but soon as you kind of hit the, the commercial sphere, the,

there's so much more to consider.

It doesn't always work.

I do recall thinking at the time that the kind of the holy grail for all

this would be to come up with some form of prefab prefabrication where

panels could be created within a factory, which would take them outta

the, of the, um, the outside climate, which was causing this kind of risk.

And I believe that that's what you at Green Car have actually progressed to now.

That's right.

So my first encounters with Hempcrete were when I was at a company called

Lyme Technology, and, uh, probably spent eight or 10 years working

with hemp in, in that format.

And we started off as.

The enthusiastic people that you are describing.

And, uh, it really came to a bit of a head, uh, about 2009, 2010.

There was a, a bad winter and we were building 85 houses.

On site at the same time with cast in situ Hempcrete in a wet process.

But we also had a contract to to do the walls of a new Marks and Spencer's

store at a place called Cheshire Oaks.

And that came with a. Quite an onerous penalty for being late.

Uh, as far as I remember, it was 169,000 pounds a week for finishing

late which focused the mind rather.

And we decided that rather than do something in a wet process on site,

we'd prefabricated into panels.

So that was really the, the first.

Experience of prefabricating and drying panels and then taking the

finished panels to site and, uh, the 85 houses that were going through a

bad winter, uh, were all slowed down and, uh, caused all sort of frus, all

sorts of frustrations as a result.

The panels that went to the Marks and Spencer's store, everything went

as perfectly as it could have done.

And it became very obvious by the end of that, that the way forward

was prefabrication and drying in a factory rather than doing it on site.

And so for the last 15 years, that's exactly what I've been.

And so we now make panels.

Uh, so we make a, a structural closed panel, timber frame.

We cast the hemp and lime into it, and we dry it in the factory.

And, uh, over the last 10 or 15 years, that process has speeded up from something

that took weeks to, to cast and dry to something that now takes hours to do.

And, uh, you know, we have a turnaround of about 48 hours per panel now.

Chris Halligan MCIAT: Excellent.

Okay, so in terms of material then, um.

Where does most of your, most of the hemp you use come from?

Because I'm aware that in the past it was quite a common crop

for farmers right across Europe and North America, but in recent

centuries it's kind of died of death.

Where does, where does your stuff mostly come from?

Ours comes from, uh, the, the Lincolnshire Yorkshire area.

So that, that sort of area around the Humber Esry, uh, a, a company

called North Yorkshire Hemp sorry, it may be East Yorkshire Hemp.

And

Chris Halligan MCIAT: Yeah.

Steady

on.

uh, got, got to get that right East East Yorkshire hemp.

And, um.

They grow hundreds of acres there and they actually process it themselves

on their own farm processing level.

But there are other companies now springing up as you mentioned at

the beginning, it's getting more common for people to start looking

at growing hemp and processing it.

We are always confident that there are tens of thousands of

tons being produced in Europe.

So if we ever run short in the uk.

It's fine, but we've never run short.

There's always been sufficient grown here.

Chris Halligan MCIAT: So what about other, um, other constituent materials that you

might put in your prefabricated panels?

Because I know when you first started looking at this, we had been mixed

with lime and lime based mortars, but, um, um, what do you use,

what, what is the actual mixing and curing process that you go through?

Because we are putting it in a panel and it's not forming

any sort of structural capacity.

We've been able to develop some very simple low strength binders

for it, which are based on hydrated lime that comes from Buxton.

Chris Halligan MCIAT: All right.

uh, incredibly simple, uh, lime and water.

We do have a secret ingredient that, that catalyzes the reaction, but it's

essentially lime and water and hemp.

And, uh, it's all UK manufactured and

Chris Halligan MCIAT: Fascinating and comes from Bookton and be

delivered by rail as well rather than buses, which is quite nice.

Trucks, which is quite nice.

Yep.

Chris Halligan MCIAT: Hemp and all, its, its varieties, um, I believe has certain

environmental benefits for agriculture in that it's, um, it grows quite quick.

It also, I believe, can reintroduce nitrogen to the soil, but in, in

terms of its, uses a material.

What are some of the benefits of using hemp, say, in terms of its thermal

and, uh, breathability aspects?

So hemp has a, a pretty unique cell structure which gives it

some quite complex thermal properties.

So it's a pretty good insulation material, and you mix it with lime, it becomes

fireproof and it becomes, uh, mold resistant, vermin proof, and you've got

a, a rigid insulation material, but.

The thing that makes it so good from our point of view is that

it's had, it's got what's called a natural phase change property.

So within the cells of the hemp, there's a very small amount of

moisture as there would be, you know, if you've got a, a timber table that

will still have moisture in it, it maybe five, 7%, something like that.

And it's the same with the hemp.

It's got a very small amount of moisture in it, and that moisture

is capable of changing from liquid.

To vapor or back from vapor to liquid and that can absorb or release quite large

amounts of energy when it does that.

And so not all of the heat that goes through the wall of a house

from the inside ends up coming up the outside because some of it

gets stored in the hemp and lime.

So we found that when we model the thermal performance of our

houses the actual real thermal performance is about twice as good.

The, um, as the predicted performance.

So, uh, that's one of the main benefits.

Thermally?

Chris Halligan MCIAT: Okay.

I, I, I wasn't aware of that.

So is there.

I guess being a phase change material, it can actually act as a

substitute for thermal mass and if it's remitting the heat, what, what

kind of time lag is involved in that?

Has this been measured?

Yes, it's, uh, it's.

Typically, um, sort of 12 to 24 hour time lag, but it does depend

on the time of the year and, and the atmospheric conditions around it.

But, but what it essentially means, as you say, is it replaces thermal mass.

It's not thermal mass.

It's thermal inertia rather than thermal mass, but it still means

the internal temperature changes very slowly, even if the external

temperature is changing quite rapidly.

So it means on days where you get quite.

Big temperature swings between day and night.

You don't see those coming through to the internal environment of a building.

Chris Halligan MCIAT: Right.

Okay.

And is there any difference with, say, um, condensation?

Are there any benefits in terms of its dew point or how it performs

in, um, moist warm environments?

Yes, it's a, a fully breathing wall, so it will

allow moisture to pass through it, providing you've got the right

finishes internally and externally.

And obviously that's an important factor, but it also disperses

moisture, so it's one of those.

Materials that moisture never becomes concentrated in one place because

it wick wicks it away and allows it to evaporate and, and, uh, dry.

So it's very, very good at moisture buffering.

And in fact in a former.

Role at, uh, Lyme technology.

We, we built buildings such as archives for museums because it could

create very, very stable internal humidity and temperature, which

was great for storing vulnerable things like papers and works of art.

Know someone with a story to tell or a topic to

explore email atpodcast@ciat.global to nominate a guest or a topic.

Chris Halligan MCIAT: Right.

Okay.

I mean, personally I find that fascinating.

I love the idea of buildings being living and breathing, and it seemed to be, um,

remember in the nineties and the turn of the century, there was a lot of people

kind of pursuing that line and then.

With the kind of concentration on air tightness, we seem to move away from that.

And um, one of the kind of comments that I hear a lot of the time

from lay people is that they can perceive quite airtight buildings

as, quote, living in a plastic bag.

But, um, you are offering something a little bit different,

a little bit more natural.

We, we are, but I have to say we don't really use the hempcrete,

uh, as a moisture buffering material in, in houses because you've got this

balance between air tightness, energy performance, moisture control, and in

fact, the first line of defense for control and humidity is your ventilation.

The fabric of the building only really starts to come into play if you've got

excessive moisture or your ventilation's not doing what it should be doing.

So in our buildings, we always use mechanical ventilation and heat recovery.

the breathability of the building is a secondary factor.

Um, and, and we get that breathability by using a, a vapor permeable air

tightness membrane inside the walls.

So you're getting the, the best of both worlds because as you say,

people perceive air tightness as creating a stuffy environment.

Like wearing Gore-Tex clothes rather than plastic clothes, if you like.

So the, the whole wall is breathing, but actually the, the moisture is really

dealt with by the ventilation system and that means you get the best of both

worlds in terms of energy performance.

Chris Halligan MCIAT: Yeah, it, it, it's a balancing act, isn't it?

So what about limits on use?

Is, is there anywhere that you kind of shy away from, or, you know, how

far can you push the use of hemp?

I think there are different people in different parts of

the world pushing it in different ways.

So if you go back to that sort of in enthusiast group who are always keen to

try and do something on the limit, they're using hec, creatine roofs, floors, walls.

Pretty well all aspects of a building.

We specifically use it in the external walls.

It's simple, it's safe, it's repeatable, and it delivers passive

house levels of thermal performance.

Using it in something like a floor brings it into contact with moisture.

It is an organic material.

If those moisture levels go the wrong way, there's a risk of decay.

So we, we steer away from that.

Our business is about scaling up to deliver 10,000 better than net

zero houses over the next 10 years.

We don't want to be operating on, on the boundaries of, of,

uh, the limits really, really.

Chris Halligan MCIAT: Yeah.

So obvi, obviously you are, you are almost fully concerned with

the residential, uh, sector.

has the commercial side moved forward at all?

I know that we're both familiar with the marks and Spencer.

Project and the prefabricated panels, and I think probably a lot of us hoped

that was gonna be the start of something new, but it doesn't seem to have sort

of taken off really in the commercial side as much as the residential.

No, I think there's, there's great potential

in, in the commercial side.

One of the challenges for.

People like us at Green Core getting involved in commercial projects is you

end up as a very small subcontractor to a very large main contractor.

So you might have a package of work that's.

You know, half a million pounds, but it's a hundred million pound project.

And uh, that means the contractual conditions can be very onerous for the

scale of project you're delivering.

And so it's not that it doesn't work technically, but commercially

it's just more difficult when you're in the residential sector.

And as we are, we.

We acquire land, we build houses, we sell houses to housing

associations and private individuals.

It's all under our control and, and any risks are there for us to manage without

having the contractual challenges of working with a big main contractor.

Chris Halligan MCIAT: Yeah, the risk is sort of deviating from the subject.

Um, it, it is become quite apparent to me in recent years that a lot of

the kind of obstacles that we face to creating a sustainable environment

don't rely on the technical side.

It's more in the kind of way our entire economy works, really what

we're expected to do from it.

Yeah.

yeah.

Financial and contractual and,

Chris Halligan MCIAT: Yeah.

Risk.

yeah, and legislation.

Um, all of those things, you know, build building's challenging enough,

but the other things that go round it are even more difficult at times.

Chris Halligan MCIAT: Yeah.

And, and the building industry is traditionally very conservative with

a small C you know, it's, uh, anything different, you'll have another zero on

the end of the cost plan, won't you?

Yes.

Yeah.

Which sort of brings us to things like insurance and warranties

and building regs and things.

Chris Halligan MCIAT: So in terms of that then kind of in, in using hemp in,

well I guess in the way you, you use it, is there anything which deviates

massively from what we consider to be standard practice or standard

legislation, any kind of hurdles that you've had to face in persuading people

that this isn't witchcraft basically.

It do, well, first of all, it doesn't differ wildly, but there

are still hurdles to overcome, going back to the, the fact that some of these

things can be financial and commercial.

The global financial crisis in 2008 upset all the mortgage markets and

the mortgage providers decided that they were uncomfortable with any

forms of non-traditional construction.

So they were really only comfortable providing mortgages

to Mason reconstruction.

That problem has been solved.

You know, by about 2011, 2012 the RICS and various other parties, Lloyd's

Register, came up with a scheme called Boas, the build Off Site Property

Assurance scheme, which was a way of, registering and accrediting all forms

of, of non-traditional construction.

And it's backed by all the major mortgage lenders.

So there haven't been any issues with getting mortgages on, on houses built

out of hemp or other non-traditional materials for the last 10 or 15 years.

And prior to the financial crisis there weren't any problems but That

That financial crisis just unbalanced the market.

In terms of building regs, we've always found building control to be

very open-minded and enthusiastic about the sort of things that we do.

Warranty providers are a little bit more challenging.

They like to rely on things like BBA certificates and.

Uh, British standards and so on.

So there's a longer process to, to get warranty providers comfortable.

But, um, that's, that's now essentially behind us.

And, uh, insurance companies have always been relatively relaxed, uh,

as long as things have got warranties and, uh, building regs sign off.

So there were some obstacles, but they were sort of 10, 10 years ago.

Chris Halligan MCIAT: Yeah, the the 2008 crash.

I do, I do recall it.

It just seemed to set the whole, it.

The whole sphere of sustainability back a huge amount.

And again, going back to our, our economy, it only takes a little bit of uncertainty

and risk really to get people to, um, go, oh, I'm not going anywhere near that.

We're probably both old enough to remember the, um, what happened with timber

framing at the, in the early eighties.

Um, now that died of death for a long time as a result of a television program.

Exactly.

And then the global financial crisis led to change of government.

In 2010, austerity, the code for sustainable homes was scrapped.

You know, there was essentially a lost decade in terms of

sustainability, wasn't there?

Um, and, and then it's come back on stream, and now it could go off.

Off track again because of global conditions and geopolitical

Chris Halligan MCIAT: it, yeah, it could do, but it's becoming more

and more apparent to us that it, it some form of, uh, you know, it's

a move towards more sustainable infrastructure and buildings and

construction is, is desperately needed.

You know, it's all it takes is a few giant floods and, uh, tsunami

to get people to concentrate the

Hmm.

Yes.

I think the, the other thing is.

A lot of people feel that.

To do something sustainable, you've got to be sacrificing something.

A actually building houses in the way that we do out of, uh,

prefabricated pan panels with hemp and lime in them produces better,

healthier, more comfortable houses.

They, they use less energy.

Uh, they're healthier and really comfortable to live in.

And they don't cost any more to build.

So why wouldn't you do it?

It, it's a bit of a no brainer.

Chris Halligan MCIAT: So in terms of longevity and lifespan obviously you,

you, you won't have got to the end of the life, hopefully any of your houses yet,

but how long would you expect housing?

You know, we, we normally design to say 60 years, but we fully expect

our ability to last longer than that.

Any thoughts about how hemp panels might last?

Yes.

So as you say, it's always seemed mad to me that, people designed for

60 years because in the life of a residential house, it, it normally

goes on for hundreds of years.

It's no different with, a panelised hempcrete house.

It will go on for centuries as long as certain things are done.

So it's all about.

Keeping water out through maintenance.

So making sure gutters get cleared out.

If a roof tile comes off, it gets replaced.

External claddings are maintained providing you do that and

there's no moisture present.

All building materials, timber, hemp, and so on will, will last indefinitely.

So I would expect our houses to be around for hundreds of years.

Chris Halligan MCIAT: Have you encountered any?

Workmanship issues in, in your projects that you've had to address and kind

of have you learned by experience from one project to the next.

Yes.

If I go back 10 years, our business plan was to supply panels to other

people who were going to erect them.

But we have found that we've had to go further down the, the supply chain and

do everything ourselves because, uh, we can't always rely on other people

to do the rest of the build properly.

So if you build a, a house on the basis that you're going

to achieve an air tightness.

Of less than one or in line with passive house standards, you've really got to

take full control of that build, making sure that you are installing the windows,

doing the air tightness and so on.

And so we've come to the conclusion that to get it right, you either

do it yourself or, and if it's not right, you know who's to blame.

It's us.

But.

The whole construction industry relies on splitting things into very small

packages to get the best possible price for them, and that leads to lots

of gaps between processes and trades.

Skills are very important, but care is also very important.

So we.

We work very, very closely with our subcontractors to

provide support and training.

We do regular air tightness tests all the way through the build process

while people are learning so that they can see the impact of, of what

they're doing on the air tightness.

I.

Chris Halligan MCIAT: I think, I think there's a lesson for the

entire building industry there.

Um, you're right about little packages being split up and, and often a lot of

the problems I come into contact with, um, are ones of kind of supervision

and education and that, and even kind of on the broader scale of, um,

sustainability, uh, I feel quite strongly that every project needs a champion.

To make sure the aspects of it tie together and, um, it seems like

you've necessarily had to take on that role, uh, on a practical level.

Yes.

I think it's, it's one of those things, isn't it?

That, uh, every time we've encountered a problem, we've thought, well,

what's the best way to solve that?

Actually, it's, it, it's for us to do it

Chris Halligan MCIAT: Do it myself.

um, yes, not me personally, but as a company, we, we

Chris Halligan MCIAT: No, I think it's, yeah.

Um, some of my friends and colleagues will be going, oh God, somebody

else that thinks he does it himself.

But anyway,

Yes.

Chris Halligan MCIAT: it was so in, in terms of kind of, um, the material

itself and say end of life options and whether it's recyclable or what

happens to it, what, what does happen at the end of the life of a hemp panel?

Well, I suppose the first thing as we talked about is,

is making sure the end of life is, is as far away as as possible the panels

themselves can be reused in their entire.

Form and, uh, we are now providing plot passports for our houses that that.

Detail what the components are and how they can be reused.

But in the worst possible case that it's not possible to reuse it, that

mixture of hemp and lime could simply be broken up and just spread back onto

agricultural land to, to improve the soil.

It's an alkaline material.

It.

It, uh, it deals with acidity in soils and it gets organic material back into

the soil, all, all at the same time.

So ultimately it goes back into the agricultural cycle

through spreading on the fields.

Chris Halligan MCIAT: Excellent.

Well, that brings us just about to the end of the episode.

I hope you've all enjoyed it.

I've learned a lot and I didn't think I would actually, because we had

talked about this previously, but there's always something to know more

about him 'cause it's a huge subject.

A huge thank you to my co-host Ian.

Um,

Thank you, Chris.

Chris Halligan MCIAT: enjoyed that.

If anybody wants to know more about, hemp or, uh, it's used in construction

or generally as a material I can thoroughly recommend, um, a small

book called The Hemp Manifesto by Rowan Robinson which gives 101

ways that hemp can save our world.

It goes far beyond simply buildings, but, um, it's full of fascinating facts.

So you've heard what Ian had to say and how wonderful a material it is.

So, so our listeners get out there and, um.

Start using it.

I think that's all we can do.

So thank you very much again, Ian.

Thank you, Chris.

It's a pleasure.

You've been listening to where it's at.

A huge thanks to our guests and to you for listening.

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