[01:04.35]In the last few lectures I've been talking about the history of domestic building construction.
[01:10.77]But today I want to begin looking at some contemporary, experimental designs for housing.
[01:17.51]So, I'm going to start with a house which is constructed more or less under the ground.
[01:24.80]And one of the interesting things about this project is that the owners - both professionals but not architects - wanted to be closely involved, so they decided to manage the project themselves.
[01:39.20] Their chief aim was to create somewhere that was as environmentally-friendly as possible.
[01:47.40]But at the same time they wanted to live somewhere peaceful — they'd both grown up in a rural area and disliked urban life.
[01:57.48]So the first thing they did was to look for a site.
[02:01.41]And they found a disused stone quarry in a beautiful area.
[02:06.37] The price was relatively low, and they liked the idea of recycling the land, as it were.
[02:14.80]As it was, the quarry was an ugly blot on the landscape, and it wasn't productive any longer, either.
[02:22.36]They consulted various architects and looked at a number of designs before finally deciding on one.
[02:31.88]As I've said, it was a design for a sort of underground house, and it was built into the earth itself, with two storeys.
[02:42.77]The north, east and west sides were set in the earth, and only the sloping, south-facing side was exposed to light.
[02:53.41] That was made of a double layer of very strong glass.
[02:59.30]There were also photovoltaic tiles fixed to the top and bottom of this sloping wall.
[03:06.57]These are tiles that are designed to store energy from the sun.
[03:11.54] And the walls had a layer of foam around them too, to increase the insulation.
[03:22.40]Now, what is of interest to us about this project is the features which make the building energy-efficient.
[03:31.26]Sunlight floods in through the glass wall, and to maximise it there are lots of mirrors and windows inside the house.
[03:40.58] That helps to spread the light around.
[03:43.18]So that's the first thing - light is utilised as fully as possible.
[03:48.86]In addition, the special tiles on the outside convert energy from the sun and generate some of the house's electricity.
[03:58.50]In fact, and it’s possible that in future the house may even generate an electricity surplus, and that the owners will be able to sell some to the national grid.
[04:12.16]As well as that, wherever possible, recycled materials have been used.
[04:18.37]For example, the floors are made of reclaimed wood.
[04:23.49]And the owners haven't bought a single item of new furniture - they just kept what they already had.
[04:31.31]And then there's the system for dealing with the waste produced in the house.
[04:36.66]This is dealt with organically - it's purified by being filtered through reed beds which have been planted for that purpose in the garden.
[04:47.37]So the occupants of the house won't pollute the land or use any damaging chemicals.
[04:55.32] It's true that the actual construction of the house was harmful to the environment, mainly because they had to use massive amounts of concrete - one of the biggest sources of carbon dioxide in manufacturing.
[05:11.90]And as you know, this is very damaging to the environment.
[05:16.77]In total, the house construction has released 70 tons of carbon dioxide into the air.
[05:25.46]Now that's a frightening thought.
[05:27.97]However, once the initial 'debt' has been cleared - and it's been calculated that this will only take fifteen years - this underground house won't cost anything - environ mentally I mean - because unlike ordinary houses, it is run in a way that is completely environmentally friendly.
[05:50.63]So, eco-housing like this is likely to become much more ...
Questions 31 and 32
Choose the correct letter, A, B or C
31.The owners of the underground house
32.What does the speaker say about the site of the house?
Complete the notes below.
Write ONE WORD AND/OR A NUMBER for each answer.
The Underground House
• Built in the earth, with two floors
• The south-facing side was constructed of two layers of
• Photovoltaic tiles were attached
• A layer of foam was used to improve the of the building
• To increase the light, the building has many internal mirrors and
• In future, the house may produce more than it needs
• Recycled wood was used for the of the house
• The system for processing domestic is organic
• The use of large quantities of in construction was
• But the house will have paid its 'environmental debt’ within