The bicycle. Revolutionary in its time, of course,
but then we added, um, electricity!
Oh, my word!
HE LAUGHS
You see, it's great fun. Pretty eco-friendly.
But there again, we humans, we don't like to rest on our laurels, do we?
Huh? We want more!
Yes!
We are relentless pioneers.
We push, we strive.
We want to be the biggest, the best, the fastest.
Just look at this.
It is fully electric.
This is planet-friendly super performance.
I mean, just imagine if your home
was built to those kinds of standards.
Now that could really take off.
A London-based environmental consultant, Duncan,
runs a company that takes contaminated land...
That's not good.
..like this old fuel storage yard, and cleans it up.
It did smell a little bit fruity, didn't it? Yep.
I started doing this because I care about how we treat the planet
and hopefully, you know, we do make the world a little bit cleaner,
a little bit better.
His partner, Liz, also deals with toxic situations,
but of a very different kind.
She's a top divorce lawyer, whose clients have included
Diana, Princess of Wales
and Bernie Ecclestone's wife, Slavica,
so she's gained some notoriety.
I've been referred to as a terrier,
I've been referred to as "the poisonous dwarf",
"the gnome from hell"...
Honestly, if someone is being rude about me, I just think
I'm doing my job.
But for every inch of me that is pushy and doesn't give up,
there's about 20 foot of Duncan that is pushy
and doesn't give up even more!
They'll need all that gumption for their radical self-build.
They bought this North Cotswolds plot three years ago.
It came with plans for a revolutionary eco-home,
potentially a UK first.
For me, that is just so exciting,
but it's going to be quite daunting.
I've never built a house before,
and I'm kind of starting at the extreme end by building
an incredibly complicated house and it might just not work.
For this job, I'm going to be the client
and Duncan's the project manager, so it's going to be interesting
to see how we work that one out between the two of us.
Especially as Duncan will leave their London terrace
to live near site,
leaving Liz dependent on his updates.
So, do you think we'll still be talking at the end of it?
If we are still talking at the end of the week it'll be a miracle!
That'll be closer to the truth, that's for sure.
Oh, I think it's going to be quite challenging.
It is the most combative of relationships.
Banter aside,
living together in this Cotswold village is their goal.
Hello. Hello. Hello.
It's very, very quiet.
It's very, very pretty.
And what brought you here? Have you been here long?
We were looking for a project for three years.
You were looking for a project, I was looking for a home.
You were looking for a project
because that's what you do, being an engineer. Yes.
Yeah, and you were looking for somewhere to live, simple as that.
Yes, somewhere to put my furniture. Yeah!
When we came here, we thought this just felt right.
Duncan and Liz's plot is a short stroll.
They spent years fighting the planners
to adapt an inherited design.
So, this is the site, Kevin.
I love the plot.
So, what we are trying to build is the UK's first
Passivhaus Premium house.
But what's Passivhaus Premium?
So Passivhaus is all about being thermally efficient,
energy efficient, and the building being airtight.
And for Passivhaus Premium,
you have to generate four times the energy you use.
So it's like a miniature power station?
It's exactly that.
On a sunny summer's day, we will be supplying over half the village
with its electricity, just from this one house.
That's amazing!
Now, how much do you buy into this?
Frankly, I'm not even sure I really knew what
a Passivhaus was when we embarked on this.
But, having learnt, I think it's admirable.
Because you're the first to do this in the country,
how do you know it's going to work?
We don't.
SHE LAUGHS
This experimental powerhouse was originally designed
by one local architect and modified by Duncan
with a second architect.
On a stepped site cut into the hill,
Duncan will use shallow polystyrene trays
filled with concrete to form insulated slabs
and retaining walls.
The continuity of the thick insulation
under and around the building is essential to make the airtight,
and energy efficient house needed for Passivhaus certification.
A basement steel frame and concrete decks for the floor above follow.
Then comes the structural insulated timber panels
to form the superstructure.
It will be hard to assemble,
huge and geometrically challenging,
with three pitched roofs
as asymmetrical as the eight glulam portal frames
that Duncan's introduced.
There's more insulation to come,
plus a 23-metre wall of heavily shaded triple-glazing
to the south, to drink in the sun's heat in winter.
Duncan and Liz don't want their home to flaunt its green credentials.
It'll be luxurious, with 5.5 metre ceilings and monumental stone walls.
But their home will be high-tech green,
with a recycled paper and plywood kitchen,
overlooked by a yoga mezzanine for Liz.
The long, pitched roof on the west side will contain a library
and a sitting room, reaching out towards the horizon.
While under the third easterly pitched roof will sit
two studies and a garage.
Duncan's also added a helical staircase
down to the lower floor.
Four bedrooms and bathrooms will radiate out from it,
alongside a dressing room for Liz,
and a wine cellar for him.
But, the gold star here is getting Passivhaus Premium.
Duncan has to generate four times the energy he needs.
The plan was to stack the 660 square metre roof
with solar panels,
but Duncan is set on a new solar fabric instead.
A plant room will direct their electricity to the house,
the car,
and back to the National Grid.
But the ambition is set at an all-time high here,
especially given the scale.
The house is nearly 800 square metres.
I would like you to go and stand where the corner of the building is,
and, if you don't mind Liz,
if you don't mind standing where that corner is,
and I'll sort of hover in between you.
Oh, my word, it's a heck of a long way.
Am I in the garage, sweetheart?
He can't hear you, he's so far away!
Right! So, where are you now?
So the bedrooms are all along here.
I don't understand why it's so big.
Because it was designed that way and we couldn't face
going through another battle with the planners
to build something sensible.
My word. Do you not think it's going to be a monster?
No. I think... I think if we get it right internally
it should just feel homely. That's the dream.
It's terrifying.
I have to ask you how much you think the whole thing is going to cost?
We've got a budget of £1.2 million.
What happens if it comes in at 1.4 or 1.8?
I keep working. That's the first resort.
So, the dynamic here is that Liz is the client, I'm the project manager.
I stress about money, and he says it'll be fine.
Cash flow isn't all down to Liz.
They have two-thirds in savings,
and they'll also take out a loan on their London pad.
How long do you reckon to build, in your mind, Liz?
I think at least two years.
He says 18 months.
But what's your weakness, darling? Finishing.
Yeah.
I'm not moving in until it's finished to my standard. OK.
It's interesting to know this early doors, Duncan,
because we can then hold you accountable. Yes, please!
Wow.
Passivhaus Premium, eh?
But you see, I think that's where we are all going,
because this house is the future.
It will generate four times more energy than it needs.
It will be super-efficient.
And, if he can bring it in,
this project will be epic.
Duncan wastes no time.
Days later, he's carving out monster-sized
footings with a local groundworker, Sam.
When this build came about,
there was a few people that weren't over the moon about it.
It's going to be a horrific-sized house,
but that's up to him to live in.
It's also going to be horrifically exacting.
Passivhaus Premium detailing starts with the foundations.
We need them to be very, very level
so that the structure fits on top of it without any gaps.
If we don't build accurately enough,
we won't hit the air tightness criteria,
we won't get Passivhaus.
It is all Duncan's responsibility.
I've got to do something, I've forgotten to measure it.
He has a tiny 2.5cm tolerance across a 50m site -
it's easy to dig too deep.
I think we've cut it too low. We need to put some back.
And this is just day one.
It's a month later.
Duncan, all six foot two of him, has been staying in this pub garden,
while he sorts out a rental.
It's tiny, but it's warm,
it's dry, bed's comfortable...
..but obviously I miss Liz.
Duncan spends weekends with Liz in London,
but today, she's getting a train up to inspect the site.
Picking Liz up is... It's going to interesting.
She hasn't been to the site for weeks
and it's changed hugely.
I think she's going to get a big, hopefully surprise, not shock.
Liz is the client here, dependent on updates from her project manager.
Hello, how are you doing?
I'm very good.
But there's still room for energetic debate.
But it's still your idea to have a dry-stone wall
going around the parking area around the garages, is that right?
Coming from the front? Coming from the...
No, as we discussed last night,
we're going to do that with gabions.
Well, I wasn't exactly sure.
Don't patronise me, you twat!
These two don't seem to be quite on the same page.
So, come and have a look at what we've done.
So, this is it, yeah?
My God!
Holy shit.
I hadn't envisaged...
This!
I hadn't envisaged anything this big.
It is quite... It's huge! ..chunky.
Come on we could literally build a shopping centre in there.
So hard to imagine.
I'm staggered, I really am.
OK.
And this is just half the house's footprint.
In the Cotswolds, Duncan, our wizard environmental consultant,
is getting his radical eco home out of the ground.
He's now three months into this 18-month project.
Hey, how are you?
Very good, thanks.
Today, Duncan's team are finishing the insulated trays
that will hold the first slab.
So this structure, which is...
I can hear it squeaking!
It's made out of expanded polystyrene
and that acts as a tray, for that much concrete.
Yes.
They use so much less concrete.
Exactly that. We've got four slabs going in,
this is by far the smallest. Yeah.
It's also outside the Passivhaus envelope
so we're doing it first.
Basically, if we make a mistake with this it's not that disastrous,
whereas once we're into the Passivhaus part, it's disastrous.
The one thing you can't compromise is the thermal insulation.
Exactly.
It's like a wrapper all the way round. Yeah.
Getting this mammoth structure airtight,
a must for his Passivhaus premium certification,
will be a minefield.
So surely Duncan, without any experience,
has picked a specialist architect?
Hello. Hi.
You've got yourself an outdoor office.
Er, no. He's appointed Laurence Becker.
He met her on a Passivhaus course.
I'm not ashamed to say, I've never been great at maths.
I failed the Passivhaus designer test,
but there are two ways to get your... I'm sorry?!
No, no, no! There are two ways to get Passivhaus certification
as an architect - to build a Passivhaus or pass a test.
The test is notoriously hard.
But, building one will be no walk in the park either.
It requires rigorous external assessment.
This is the Passivhaus planning package.
Within this book, there are at least 30 spreadsheets.
Oh, wowzer.
You've got performance data for every pane of glass, every...
Every pane of glass basically, yeah.
So if he changes the windows...?
Every change has to be inputted into this.
And you have to do that. I mean, if it drops below a certain standard,
you know you're not going to get certified. We won't get it, no.
Your role is integral to the success
of the building getting its accreditation, yes?
Yes, it scares me sometimes. I wake up at night and think,
"Have I done this? Have I done that?"
But that's what makes it interesting.
Blimey.
And the colossal size adds to the challenge.
Even pouring the concrete walls on Duncan's first slab,
three weeks later, is problematic.
They're so tall, he's had to leave the insulated formwork
at half height, at 1.5 metres tall,
to make sure the concrete gets to the bottom.
As soon as the guys have filled it up to half a metre,
we're putting these polystyrene blocks that we've got lined up.
We're building up more wall behind them.
And the idea is that we stay ahead of them,
and we don't get lapped.
If we really can't stay ahead of them,
we're going to waste the concrete.
And so, this risky game of cat and mouse begins.
It immediately becomes hectic.
Most blocks fit, but some don't.
We're slipping behind.
They're half a wall ahead of us at the moment.
There's a greater worry.
The higher the concrete, the bigger the pressure.
Suddenly...
Oh, shit. OK.
Everything has to stop while they fix the rupture.
So the risks if we continue,
we're putting more weight into the wall,
the wall will burst somewhere.
Splitting the concrete pour over several days
could compromise the strength of this retaining wall.
There's a slight bulge...
So once it's propped,
Duncan is itching to finish the job.
Do we feel brave, or do we not?
So, at 4pm, he decides to go for it.
It seems nuts.
Oh, hell, yeah, this is definitely a risk.
So what we are banking on
is that the first concrete that's gone in is now starting to cure.
It's up to Sam the groundworker
to cautiously pour the last nine tonnes.
But would he have made the same call?
Probably not because it's not worth the risk.
But I'm not a risk taker that much. It's not my decision.
30 anxious minutes pass
and it's still standing.
All the concrete has gone in pretty much.
We're just putting the last bits of rebar in.
I think we got away with it.
What a lucky escape.
Duncan now feels reassured
to pour more concrete, while he also finesses plans with Laurence.
I did have to move one of the beams
so that the soil pipe could go down and across.
Yeah, I saw that.
Within six months, the basement and ground floor slabs are in.
And then nothing happens for weeks.
Except some dry-stone walling
by the assistant site manager, Jasmine.
I'm a little frustrated that we're about two months behind schedule,
I think, and that is a mix of reasons.
We've got a very complicated build
and we appointed two contractors
and managing the interfaces between them has just taken a long time.
They're still stuck in the design phase
with their drawings bouncing from site
to David, who's local and supplying the steel frame,
and Gary in Shrewsbury,
whose firm is responsible for all the timber structure.
It's been a bit of a journey, I have to say.
It is quite complex in the shape, the geometry of it.
I would say the most challenging Passivhaus scheme
we've been involved with personally, yes.
We'd normally expect to design this in about a month.
It's taken us about three months, I suppose.
I think it's mainly because of all the changes we've had to make
and also coordinating with the other people working on it.
But David has now done the hard part,
so within days, ten tonnes of steel at £29,000
is finally being craned into the basement floor.
Liz is paying her once a week client visit.
I don't want to get hit by steel. I'm retreating.
While Liz heads to the sidelines, Duncan takes a front seat.
This is really exciting to see -
we've waited a while for this,
so it's great to see it all happening now.
HE CHUCKLES
Duncan and Liz are experiencing the project very differently.
I've been really quite divorced from what's been going on on site,
Duncan sends me photos, we talk about it.
We talk about virtually nothing else in fact,
but even so, not being here, not living it with him,
makes a big difference, and it is a strain on our relationship.
But Duncan's focus is elsewhere.
Now the steel is taking shape,
he needs to get the drawings signed off
for the huge wooden superstructure that comes next.
We've got one or two important issues
that we're just trying to clarify,
and then from the moment we sign off it's eight weeks.
But in the following days,
as concrete beams for the ground floor are hoisted
onto the finished steel frame,
the drawings are still not finalised.
Working late at his firm one evening, Duncan is gloomy.
Just a quick update for you.
I had a pithy conversation yesterday
with the timber frame company.
He'd promised the drawings early part of this week
and obviously they haven't turned up again,
and he said that's our fault, apparently,
because it took us so long to sort the steel out.
We haven't changed anything since we sent them.
No, so that's just disappointing
but there's not a lot I can do, other than...
..other than have conversations with him.
Throughout this project,
Duncan and Liz have battled with the restrictions
of the Covid pandemic,
leaving Liz increasingly isolated in London.
Gosh, you're in the office!
Yes, that's right. I'm fixing IT.
Video calls are just not the same as him coming home in the evening
and actually being able to have a real shared life together -
we just don't at the moment.
I do get lonely, and I miss Duncan.
It's just me and the cats now.
Liz does go to her office, but it's nearly empty.
I'm not exaggerating, I've been quite depressed by it.
Just literally getting up, going to work,
coming home, going to bed, getting up, going to work.
I've found it very challenging.
For Liz, the move to her new home can't come soon enough.
But a glorious summer passes with no sign of the timber frame.
It takes till Autumn, a year in,
for the £240,000 structure to arrive.
And Duncan is giddy.
I'm excited! I'm genuinely excited.
The original date we were given for this arriving is 19 weeks ago.
Now at least it's here and we're moving forward,
so I'm just really happy it's here.
So is Gary, who is responsible for this timber structure.
He is, however, convinced he's on schedule.
I'm not really sure we are late, if I'm honest.
We don't make anything until it's physically approved -
in other words, Duncan's signed it off,
so we're about ten weeks from approval to starting on site.
I hope these two were on the same page in the design phase,
because the timber has to fit Duncan's slabs precisely.
That means the pressure is on me.
If it's in the wrong place you know, that's my mistake.
Normally, the base and panels marry easily.
But not here.
We're finding we're about sort of 40 to 50mm out
of where we thought we were going to be.
Apprehensive.
A three metre drop between floors,
and 600 square metres of panels make it hard to align it all.
I think it'll be 50mm too short.
Precision has to be key.
If we spike this side... Yeah, spike that side.
Basically we don't want gaps.
Gaps are not good. Gaps are bad.
It's worrying that Duncan won't know if it's fully gap-free
until the final airtightness test.
But at least he has the satisfaction of seeing his house take shape.
Just taken a photograph and sent it to Liz.
Been trying to keep her updated.
It's a good thing too,
because by week five the changes are breathtaking,
as in come the eight giant portal frames.
It just looks amazing.
I mean, we're finally seeing a 3D building.
Each of these frames is asymmetrical -
they're all slightly different,
and that's purely just a visual thing.
Just for interest, just for fun.
I love it.
I am concerned it's not big enough.
Duncan doesn't however, get to rest on his laurels.
His dream, to be the UK's first Passivhaus Premium home,
rests on his solar roof generating four times the energy it needs.
But the innovative solar fabric he's found,
might fall short by his current calculations.
See here, the roof is a zig zag.
So it's got six faces, and each one shades the one next to it.
Right now, we either fail by about 2%,
or we pass by 2%.
It really is on that knife edge.
It is the key to whether we achieve Passivhaus Premium or not.
I will be absolutely devastated if we don't get this.
It is such a key part to the whole building.
The problem here is that Duncan is asking a lot from this solar roof.
He wants it to be super-efficient,
affordable and beautiful.
So, he's discounted traditional panels
and instead he's looking to newer invisible tech,
like solar tiles or fabric.
But, it's a rapidly evolving field.
This £17.5 million home in London is Eglon House,
inspired by the iconic Maison de Verre in Paris.
It has wonderfully hidden eco credentials.
So, these solar panels are sort of from another world, really.
They're generating electricity,
but you can actually see the sky through them.
It seems to be of the future.
It's only five years old,
but it's already been surpassed by more advanced models.
And this is the dilemma Duncan's facing.
But he's prepared to invest in the future,
pay the money for a system which, after all,
may be out of date in five years.
He's also prepared to accept a system
which may not be quite as beautiful as this.
But, the one thing he dreads,
if he doesn't get Passivhaus Premium,
if he doesn't get enough solar on his roof,
then he has unutterably failed.
Tallinn, Estonia.
Having failed to find a UK solar roof material
that was beautiful, affordable,
and potent enough for his mini-power station house,
Duncan has flown here.
The roof has proved more problematic than I thought.
We did have a UK supplier
and we've had some issues with them,
and hence coming to Estonia to look at an alternative.
Instead of the invisible solar fabric he'd wanted,
the alternative is more obvious - glass and metal roof tiles.
They're about 60% cheaper,
a great saving, if they work.
So, this is your overall design
of your roof surfaces and planes.
You see, we have all the trees that have to be there.
Jan is calculating how much energy the roof will generate,
but accuracy is key.
That's actually not a chimney, it's a soil vent pipe.
Oh, right. And those two don't exist.
Any shading trees need to be to scale too,
as they'll affect electricity generation.
So how high have you put those trees?
I think high enough.
Because the trees on the east side are mature ash trees -
they're about 40 metres high.
The height of them is not 40 metres.
Clearly, working long-distance will be challenging,
but Duncan wants to go ahead.
I'm taking on a lot more risk in doing this,
but there's a cost saving for me,
which hopefully makes it worthwhile.
Indeed. Duncan's already spent £800,000 of his 1.2 million budget
and he's still building the basic structure.
For the next few months,
Duncan and his assistant site manager Jasmine
prep the enormous 660 square metre roof to receive its solar skin.
We good?
Yeah, that's good for me.
By the time we finish, we'll have put 1,600 pieces of insulation in,
500 pieces of wooden board,
and 4km of roof batten,
which is this stuff on the roof.
Surely he could subcontract this tedious bit of work?
We're doing this because, well, because we can.
It's fun.
It beats working. It just keeps us busy!
He's even designed the upstand for this...
The enormous £9,500 skylight for the stairwell.
This is the widest bit of glass -
weighs very nearly a ton.
The upstand has to support it,
and it's the first one I've ever built.
Yeah, just, that end slightly before this. Yeah, yeah.
I'm just worried that this frame starts buckling,
which would break the glass,
or the whole lot just starts moving south.
Neither is a good result for me.
If it fails, the cost of this crane,
these men, this glass,
is around £20,000.
Yeah, the next five minutes are going to be literally make or break.
Do you want to check that before we drop it - the width?
You happy it's that way? OK. Yeah.
Painfully and slowly, the glass is eased in.
OK.
Shall we lower it down?
Oh, my God...
Yeah, I'm down,
and she's in!
So far, so good.
Yeah, but they're still holding it on the crane
at the moment, so we're not quite at the last moment of truth.
Look at that!
Definitely happy.
Duncan is 18 months in, and he should be finished by now,
but he's only halfway.
However, there's more here than meets the eye.
This house is deceptive and cunning.
From the lane,
all you see is what looks like a tractor shed,
but actually, underneath the folding roofs of this building,
it grows towards the south.
Look at it - this giant space!
Architecturally, it's extremely exciting,
but it is huge.
Broaching a sensitive subject. You said you'd be finished by now.
We are a little bit behind schedule.
The timber frame arrived late,
and then the building's a very complicated shape.
The roofs are doing that and they're doing that
and they're doing this and that. Exactly.
So there's an awful lot to align and try and get right.
And tell me about the money then.
I think we are under budget at the moment, aren't we?
We are under budget, yeah. How so?
The big saving so far has been the Estonian roofing system
and in really simple terms, almost the longer we spend building this,
the less expensive it gets
because the more Jasmine and I do.
And, you know, my time is free.
Just as well really.
The next step of sealing the house airtight is onerous
and will take months.
But Duncan thinks a new product will help.
Ordinarily you'd be taping all of these joints.
Yeah. Every single joint in the external walls
of the building, we'd have to meticulously tape.
Where we've brushed is where we've got quite a deep groove
and we want to get something a bit gloopier and a bit thicker
than we're going to spray, and the expanse in between
we'll just spray over.
It allows idiots like me to do it.
Or me?!
This spray-on airtight layer prevents leaks,
allowing the insulation to really do its job
and minimise the heating down to Passivhaus required levels.
Duncan has 900 square metres of spraying ahead of him.
You're going to get really sick of this colour.
That's for sure!
What follows is some slower painting, and more glazing.
At last, 26 months in, it's watertight,
and Liz is able to get involved with the interiors.
But it's a heck of a pad to kit out.
I've never, ever had to deal with a space
this big and tall, and it's...it's quite daunting.
They've consulted an interior designer
because they can't seem to agree on very much.
I mean, I'm slightly reluctant to go with the very light one
because I'm worried it's going to make it feel very cold.
Like you, I think the slightly darker colour works better.
Now I don't know that though because now I'm thinking that it just looks
a bit like somebody's peed on it.
The client is...
..not as decisive as she could be!
Urghhh!
I don't know.
It's even harder choosing between their two kitchen layouts.
So, let me have a look.
There are two options for the kitchen -
one has one island, one has two islands.
I'd like to see two, I think Liz would like to see one.
With the two island option,
you can put your sink and your hob out here,
and then you have your guests sitting here.
To be fair, she really struggles to visualise how things will be.
The island isn't going to be where you've got your fat feet
because you've got your wall,
and then you've got to have a gap between the island and... Liz.
As it's drawn, the single island option is here.
But I know what'll happen - whichever one I prefer,
we'll end up building the one Duncan wants.
We just will.
It's just easier that way now.
All talk of kitchens is put aside though,
in the run-up to Christmas.
Finally, after spending a whole year designing his roof...
It's a bit slippery up here today.
..Duncan gets his Estonian solar panels.
Including the fitters, it's costing a hefty £118,000.
The roof is the one thing
that turns this from a normal Passivhaus into Passivhaus Premium,
so the roof is the really big innovative item on the build.
It's so cutting-edge, it's the company's first UK job.
Gerd, who's in charge, is impressed with the scale.
There will be 300 panels on this roof.
Plus, we have 1km of cabling.
I would say that this is the biggest roof that we have done.
And yet, the Estonian team want to finish in just 11 days
and be home for Christmas.
It means working into the winter nights.
And I say, "Lights!"
Like daytime!
Or night-time.
Actually, two rows more and then we can measure the power.
With those lights I would be able
to get some kind of voltage out of it -
it will show that we have power and everything is correctly connected.
It is a really exciting moment.
I want to go up and just see it.
Let's see if it's showing something...
Yay!
Goddammit, I was right!
Ha! Woo!
Super happy.
It's all working. That's the first power off the roof.
It's a big thing.
I can finally charge my phone then!
Of course, it's what happens during daylight hours
that's going to be vital.
The installers take an extra week to finish,
it's just so big.
From then on, the onus is connecting it inside and to the grid.
By Spring, nearly three years in,
it's up and running.
I didn't think it would look this good.
This just looks like a roof. They're invisible.
And are they generating well?
On a day like today, we're generating about 230 kilowatt hours.
To give you an idea, a typical medium house
uses about eight kilowatt hours a day.
So, that's a lot!
You are the living embodiment of what excites me about self-build,
which is that you are using innovative technology
and making it work.
Duncan still needs to prove he can make four times the energy they use
to get his Passivhaus Premium prize.
But this house is still so embryonic.
I'm sorry to say this, but upstairs hasn't moved on a huge amount...
Shh! ..in 15 months.
Shh! Come downstairs -
it is a bit different downstairs. Follow me. Yeah, yeah.
It's just, you know, psychologically good for me to see some progress.
Oh! Big, circular room. This is good.
Very nice to see it now.
I just want to see it done. THEY LAUGH
The four bedrooms and four bathrooms are just shells,
with no walls or floors.
First fix is barely under way.
You did say you weren't going to move in until it was done.
That was a while ago.
I think I'm willing to compromise now,
just because I'm so keen to get in now.
Liz seems to have given up on Duncan completing
this passion project any time soon.
You are slightly addicted to it.
I think even more than that, I enjoy the design process
and I have a real weakness
where I tend to over-design and keep redesigning
and reiterating,
and I have to break myself out of that sometimes
and realise that I do need to finish things.
So, where are you with certification?
We need an airtightness test. Yep.
We need to submit our very complicated computer model.
And? And the third thing is about energy generation.
We're nearer the end than the beginning.
That is such a fine philosophical way of looking at it.
Man, there is so much to do on this project.
There are so many kind of questions hanging over it.
And the biggest is, will they get Passivhaus Premium status
and set a new benchmark for UK housing?
I hope so.
But Duncan might take so long he won't be the first,
and then he'll be devastated.
So, come on, Duncan. Crack on!
Just over three years ago in the genteel North Cotswolds,
Duncan and Liz began their high voltage mission
to build an electricity-generating Passivhaus Premium home,
potentially a UK first.
Well.
This is beautiful.
I can see why Duncan and Liz were seduced by this countryside
and its rolling hills,
just as I can understand why Duncan was seduced by the...
the high environmental ambition of this project.
And I also understand just how addictive building can be.
You don't want to stop.
And, as Liz says,
Duncan is not a finisher.
So the question remains then, doesn't it,
just whether he can, will, or indeed has, finished...any of it?
I approach, then, with trepidation.
But it's been five months since I was last here,
so anything is possible.
Wow!
Big, curved, beautifully made wall.
That's pretty, glinting in the sun.
Looks like a building!
Albeit half clad.
Oo.
This, then seems a tale of two halves.
Half of it elegantly detailed -
a slick, sleek roof
and an ebony timber skin.
Half of it, however, undone.
Hello! Hello. Hi!
Hi, Liz! Hi, Duncan! How are you both? Good to see you.
Very good. Yeah!
Nice to see you again. Great to see you.
Yeah! How have you been?
Very good. Very busy.
Well, it's black and blue.
Slowly becoming blacker.
Hmm. Yeah.
And what I particularly like driving in,
is seeing two sheds - it sort of completes the illusion almost.
You know? It's definitely getting there. Yeah. Yeah.
And they don't look too big either, when you drive in.
Not from this angle. No.
You try nailing the cladding on them - they look big then!
I bet you wish you'd built a slightly smaller house. Absolutely.
Then it would be finished. Possibly. Possibly.
Hey, can I charge my car here, by the way? Yes, you can!
Can I steal electricity from you?
Yeah! It's all up and running. It's all good to go.
That is great!
Wonderful.
Clean electricity from the magnificent solar roof,
charging my car, for free!
But, given the boggy, undressed exterior,
I'm bracing myself for what's to come.
Come on in.
We're going in the front door!
We are indeed.
Posh!
Oh, this is lovely!
This is sharp and different.
We have been working hard, Kevin.
Still a little purple!
Well, we can't quite let it go. You know what it is.
But actually, you've built... These are all new, these stone walls.
Yeah, we're really pleased with the way the stone's turned out.
Yeah. I mean, it's taken a timber-framed building
and made something monumental of it. Yeah.
Yeah, it's good.
There are glass balustrades yet to go in,
but it's already looking promising.
So, what about the big entertaining space next door?
Holy Moley!
Well, this space is a triumph.
Oh, and the purple's gone and the sunlight pours in
and it's pretty stonking. It's amazing.
Yeah, it's fabulous.
Though the ceilings are high,
the space seems to have shrunk to a domestic scale.
What will be the living room and kitchen is almost...cosy.
Are you living here now? Not yet, no.
But, I mean, you've furnished it. Yeah. We're just trying to get
an idea of what it's going to be like. Well, good for you!
It suddenly looks domestic.
It doesn't feel like somebody's large garage.
Yes.
Do you know, there's something that is so apparent now,
and that is how that wall of glass is cranked so much,
it's swung out as though it's already opening out into the garden.
It's really... It's a great thing.
What's also joyful is the continuation of
the epic glulam purlins through the wall
to support the huge outside overhang
that fans out into the world beyond.
It also shades the triple-glazed wall beneath in summer,
while allowing the lower winter sun to heat the house.
Clever design.
And here, design drives the quality, upstairs and down.
Oh!
This has turned out to be
like a beautifully sculpted piece of shell. It was looking quite clunky.
Yeah, it was. It was definitely ugly duckling.
And we're slowly, slowly transforming it into a swan.
OK, so the house isn't finished,
but actually, that's not the important thing right now
because today, Duncan's watershed airtightness test is happening.
And that's worrying
because he's just made a massive hole in the wall!
This is a pet-friendly Passivhaus-compliant cat flap.
So, cat comes along,
and comes up to the cat flap...
BEEPS Oh!
It's got seals and everything, so it's completely airtight.
Then it shuts and the building is sealed again.
Oh, and it's got a special safety device,
so it doesn't chop the cat in half.
At around a grand and a half, it had better work
because Kym Mead, Duncan's Passivhaus assessor,
is here.
He has approved the architect Laurence's dreaded Passivhaus
planning package, and he's satisfied
that four times the electricity needed here will be produced.
But one thing remains to elevate this house
to Passiv prime status.
Hello, Kym. Hi.
How are you? Yeah, good thank you.
Yeah. You can tell it's serious
because there are loads of tech boffins in attendance.
So, this is the last piece of the jigsaw.
This is the last piece of the jigsaw, yeah.
You confident?
Hopeful. Yeah. I am.
Hopeful.
Scary.
Scary requirement.
Unleash the fan!
We're off.
The fan blows air into the building to pressurise
all 1,600 cubic metres of it,
allowing the air leakage to be measured.
Modern houses score around five air changes per hour.
Duncan has to score 0.6 or less.
Yikes!
So, Jack, what is it?
So, the average is...
0.415, which is... Fantastic! ..good result.
You passed! Yeah! Are you happy with that?
Yeah, very happy. Well, congratulations,
because I think... Thank you. I think it's an epic building
and it's an epic result actually,
to be, and as you will be now, the first in the UK.
Got there! Ah!
Thanks.
Look, I have got ahead of myself.
Duncan has still got a last airtightness test to go
and some final paperwork on completion,
but it's nearly a dead cert.
So, at what cost has this all come?
How much will you have spent by the time you get to move in?
We will have spent 1.25 million.
OK. And the great advantage about a house like this
is the running costs.
It has negative running costs. It pays us to live in it.
But the Grid caps the amount of energy you can sell back to it.
That's right. So, over the year, we should be able
to power around four three-bedroomed houses.
Because of the cap,
we're actually able to support about two and a half.
And that surplus? Dissipating. Just not doing anything?
It's a battle, Kevin. It needs a house like this to put pressure
on the government to say we need a Grid
that is designed to accept houses that generate electricity.
So, great that you're meeting your performance targets.
How are you coping with the emotional stress of all this?
Yeah. It's been three years since we've had a shared life.
Three years since we've just sat down and had dinner
and watched the television together.
There's definitely been a price to pay.
In your mind, when's it going to be done?
DUNCAN SIGHS
Define done.
Done - when snagging turns into maintenance.
OK. 18 months.
Are you happy with that?
I will be happy with that if that is what happens.
LAUGHTER
One day soon, this will be a glorious place to live,
and a certified UK first.
So, if you think that this house is just too far
ahead of its time,
then let me tell you, it's not,
because the Grid is already working very hard
to find ways of buying electricity back in large quantities
from people like Liz and Duncan - from householders.
And for another important reason, too.
Because the self-builders of this world
are the real experimentalists.
Not the house-builders, not developers,
not housing associations.
It is the self-builders who take their own money,
hard-earned,
they take their own sweat and enthusiasm and energy
and procure some of the most innovative ideas,
and some of the most experimental technologies
you can find in building on the planet.
People like Liz and Duncan.
They are right out there at the margins of society,
showing us what the houses of the future will be.
I mean in 20 or 30 years' time,
we could all be living in houses
that are power stations, just like this.
So for that, I salute them.
Back in 2018,
Leigh and Richard began converting a ruined watermill into a home.
Have you done this before?
No, we're complete novices. We just fell in love with it.
It was instant.
But, by 2021, hampered by the pandemic,
the work was unfinished.
I'm absolutely knackered.
There isn't any money left.
Two years later, I'm back.
That's what this building needed.
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