- This is the Hill House in south-west Scotland.
It was built in 1902 using design and construction techniques that were
years ahead of their time.
It's an important bit of architectural history,
but because it was years ahead of its time,
it was also experimental.
It turns out that the house exterior just soaks up all the
heavy Scottish rains, and lets the water in.
120 years after it was built, this whole building
is slowly cracking and crumbling and dissolving.
The first step of saving this house is to dry it out,
slowly and carefully.
The problem is, it rains 190 days a year around here.
So the National Trust for Scotland
had to build a very big drying room.
- The Hill House is so important. It is globally known.
We attract visitors from all over the world
in a pilgrimage to come and visit the Hill House.
Charles Rennie Mackintosh is definitely
one of Scotland's most famous architects and designers.
It is Mackintosh's domestic masterpiece
and really is so ahead of its time.
When you walk through the front door,
when you picture what was essentially a Victorian family
living in this house, you realise how forward-thinking
Mackintosh was in his design.
He used a material called Portland cement on the exterior.
There is no lime at all used on site as well.
We're located in one of the wettest parts of Scotland
in Helensburgh so it really was a recipe for disaster.
The Hill House has been described
as "dissolving like an aspirin in a glass of water".
The box basically buys us some time to dry the house out,
shelter it from around 86% of the elements.
It acts like a giant umbrella
and shields the house from the weather.
- The walls in this box are made of chainmail.
If you go and order a modern armour costume
with a chainmail vest, it will be made of this same stuff.
It's more than 30 million rings of stainless steel
linked together, weighing eight tonnes.
The roof catches most of the rain and the chain mail catches
what blows in from the sides,
but it also lets air through for ventilation.
It lets bees and other insects through to pollinate the plants in here.
And it's all recyclable afterwards because it's steel.
You just melt it down into something else.
- The box is made up of 32.4 million individual chain mail links
that surround the house, in the worlds largest sheet of chain mail.
In terms of construction, it took nine months.
It really is one of a kind. It costs around £4,500,000.
If you were to cover the house completely,
it would be at risk of suffering from environmental shock
and it would cause more damage than good.
The box style allows the house to breathe, that is really important.
It would dry out too quickly and it would cause damage
to the exterior and, indeed, to the collection inside the property as well.
Before, you were able to visit the house,
and it was here on its own and it was amazing,
but the box adds another level.
There are walkways all around the property.
You can walk around the perimeter of the house,
even up and over the top,
seeing the house from aspects that Mackintosh himself
would never even have seen.
What you're seeing at the Hill House is conservation in action.
- They didn't need to add the staircases and gantries and ramps here.
But if you block this house from public view
for the 15 years it'll take to dry out and repair,
then there's a chance the public are going to forget about it.
It'll look like a construction site, an eyesore.
If instead you highlight it,
you create something one-of-a-kind like this box
and you let the public see the house from angles
that will likely never be possible again...
well, then, you're not just preserving important architecture.
You're promoting it.
And for me, that's the cleverest part of all this.
I wouldn't be here, you wouldn't be watching this,
if it wasn't for the box.
It was built in 1902--
[laughs]
There's one more step than I thought there was there!