1Good morning.
2In the last few lectures, I've been talking about the history of domestic building construction.
3But today I want to begin looking at some contemporary, experimental designs for housing.
4So, I'm going to start with a house which is constructed more or less under the ground.
5And one of the interesting things about this project is...
6that the owners - both professionals but not architects - wanted to be closely involved,
7so they decided to manage the project themselves.
8Their chief aim was to create somewhere that was as environmentally-friendly as possible.
9But at the same time they wanted to live somewhere peaceful -
10they'd both grown up in a rural area and disliked urban life.
11So the first thing they did was to look for a site.
12And they found a disused stone quarry in a beautiful area.
13The price was relatively low,
14and they liked the idea of recycling the land, as it were.
15As it was, the quarry was an ugly blot on the landscape,
16and it wasn't productive any longer, either.
17They consulted various architects
18and looked at a number of designs before finally deciding on one.
19As I've said,
20it was a design for a sort of underground house,
21and it was built into the earth itself, with two storeys.
22The north, east and west sides were set in the earth,
23and only the sloping, south-facing side was exposed to the light.
24That was made of a double layer of very strong glass.
25There were also photovoltaic tiles fixed to the top and bottom of this sloping wall.
26These are tiles that are designed to store energy from the sun.
27And the walls had a layer of foam around them too, to increase the insulation.
28Now, what is of interest to us about this project
29is the features which make the building energy-efficient.
30Sunlight floods in through the glass wall,
31and to maximise it, there are lots of mirrors and windows inside the house.
32That helps to spread the light around.
33So that's the first thing - light is utilised as fully as possible.
34In addition, the special tiles on the outside convert energy from the sun
35and generate some of the house's electricity.
36In fact, and it's possible that in future the house may even generate an electricity surplus,
37and that the owners will be able to sell some to the national grid.
38As well as that, wherever possible, recycled materials have been used.
39For example, the floors are made of reclaimed wood.
40And the owners haven't bought a single item of new furniture -
41they just kept what they already had.
42And then there's the system for dealing with the waste produced in the house.
43This is dealt with organically -
44it's purified by being filtered through reed beds
45which have been planted for that purpose in the garden.
46So the occupants of the house won't pollute the land or use any damaging chemicals.
47It's true that the actual construction of the house was harmful to the environment,
48mainly because they had to use massive amounts of concrete -
49one of the biggest sources of carbon dioxide in manufacturing.
50And, as you know, this is very damaging to the environment.
51In total, the house construction has released 70 tons of carbon dioxide into the air.
52Now that's a frightening thought.
53However, once the initial 'debt' has been cleared -
54and it's been calculated that this will only take fifteen years -
55this underground house won't cost anything - environmentally I mean -
56because unlike ordinary houses,
57it is run in a way that is completely environmentally friendly.
58So, eco-housing like this is likely to become...