My favorite part of Sagrada [Família], I think,
is simply that it is one of the most beautiful buildings in the world.
It's a beautiful, beautiful space.
The advice I'd give anybody to go to Barcelona
is buy a ticket and go inside.
Inside of the Sagrada is marvelous.
It's a forest.
With the sun, with the
magical light with the most uplifting
set of columns and structures that you will ever
get the experience to inhabit.
To be part of.
The basilica has 138 years old
because it began in 1882.
The first architect was Francisco de Paula del Villar.
One year later,
started construction.
Due to difference with the developers,
the project was give to Antoni Gaudí.
At that time, Gaudí was only 30 years old.
He hadn't constructed anything beyond a glove stand
at the World's Fair of 1878.
So he had no track record.
So how they chose Gaudí is another puzzle, you know, mystery
in time.
But Gaudí had no lack of ambition
and he designed a church that was more than twice as tall
as the one that [del] Villar designed.
And then, Gaudí died in a horrible tram accident.
So the first thing is that the design of the church wasn't actually complete.
But interestingly, right now,
it's a wonderful sort of irony, or not irony, the opposite – fortuitousness
that the technology available today
exactly corresponds with Gaudí's design ideals.
So, in short, we can now use machines, controlled by computers,
to cut stone to exactly the shapes that we want them to be,
including cutting out pockets and holes using CNC techniques.
So we've got bandsaws to cut the shape,
but we include the love of craft,
which I think is another wonderful aspect of Sagrada, so
we computer-control-cut the stones accurately,
and then finish them the way they always have been,
which is hand-splitting the front face.
So there's three inches, or 75 milimeters, of spare stone, if you like, on the front
when the computer's finished with it,
which is all dealt with then by hand – so that in the end,
the building looks exactly as it would have done
if it had been built in 1200 or 800 [AD].
Obviously, the project is not finished by Gaudí.
And unfinished, approximately, we have
55 percent of the Basilica is remain to construct.
It's possible to do
55 percent in seven years?
Yes, because we are using the new method,
we are using the industrialization of the process.
We are using the standardization of the
different method to construct the Basilica.
For this reason, using the new technologies, it's possible to achieve,
to reach this milestone, this challenge.
So when we were appointed, asked to help in 2014-15,
they'd set themselves a deadline of 2026
to complete the church, 100 years after Gaudí died,
and they had a puzzle that they wanted our help with.
They thought the solution involved designing steelwork.
In the end, that turned out not to be the case.
So there's a set of 12 Apostles towers, four at each entrance.
The East entrance – the side entrance–
was built during Gaudí's lifetime –
four Apostles towers – or bell towers.
The next set of four were built on the other side,
on the West entrance – the Passion façade – in the '50s.
Both of these are built using conventional monumental masonry techniques,
no different from what would happen in medieval cathedral buildings.
All of that was well and good until
the church was listed by UNESCO as a World Heritage Site.
And one of the requirements of the listing
was that we made sure that any future construction
was earthquake-proof.
So the puzzle was how do you solve that?
The solution that we found through
a lot of, sort of, technological investigation – using computers a lot,
you know, let's forget steel and let's even forget concrete for a moment.
If we go back to stone, the original idea of the church
how can that be used to make a tower that is lightweight,
that is fast,
and is earthquake-resistant and wind-resistant.
And also, the idea, from a construction strategy,
can be largely prefabricated, off-site,
so the site activity is minimized.
So it can occur in and around
the day-to-day tourism activities in the church itself.
And every surface of Sagrada, in its final design,
is a ruled surface –
a hyperboloid, or a hyperbolic paraboloid.
These are doubly curved surfaces,
but they also have one set of straight lines that define them.
They're very hard to make, actually, using
reinforced concrete, even in precast form,
because all the formwork has to be curved.
And it has to be cast accurately etc.
But interestingly, right now, they're relatively easy to make using stone.
Because we can have computer-controlled bandsaws
that can cut any shape you want under the control of a computer,
provided it's a ruled surface.
Using our computer studies about how stone actually works,
and we found, of course, that it does have this weakness
that it can't carry tension.
What we then found is if we can pre-compress it, if we can
clamp it together in some format,
then you end up with a very good structure without using very much stone.
And the easiest way to provide the clamping force
is to thread very thin pieces of steel through the stone
and then tension them, tighten them up.
So they're acting just like elastic bands
holding the stone together.
And now, we've got a panel that is rigid and firm and stable
that we can take to site and use like a Lego block
to add to all the other panels
and continue to make a tower
that looks as though it is monumental masonry.
I've worked on many buildings
and there are buildings where there's more of me
in the outcome, if I can put it like that –
where I've had more of a hand in shaping the concept.
At Sagrada, the concept's already shaped.
Gaudí shaped the concept, you know, before I was born.
And so our job is here interpretation.
And maintaining quality and making it, you know, possible, if you like.
However, despite that,
I think it's the project that I feel warmest about.
We got the beauty, in my view, of using a natural material.
Increasingly, the world has to use more natural materials,
at least we have to use materials that have less carbon
embedded in them, otherwise, we've got, you know – climate change is
bad enough already.
So we've got to do things that are more sustainable.
And stone is, you know, one of the potential solutions to that.
And then, on top of that, we have the craftsmanship angle
of using people and love and craft, in a time-honored way,
which, again, is carbon free,
to add,
to gain a whole layer from which people respond emotionally,
so people respond emotionally really well to natural materials
and to craftsmanship.
And the technology, sort of sits almost invisibly in the middle
to make it all work at a speed,
you know, that's relevant and at a price we can afford.
And so, for me, I think, the thing about Sagrada I really love is this –
even though it's a very, very special building,
the philosophy, or the way we are doing it,
is something that you can extrapolate to almost anything.
We can start making more,
more buildings out of timber
using computer-controlled machines to cut and make timber accurately.
And to use more prefabrication off-site to make site construction easier.
So there are things we can learn from all of this as well.