How Earth Sheltered Houses Work
When our ancestors moved out of caves, the first type of house they built were what we would describe today as earth sheltered housing. The simplest ones were formed by digging into a hillside (usually facing the sun) to create a living area and using the excavated material to form a new earth wall or berm to partially block the entrance.
Although the main reason for their construction was for shelter and safety, there were other hidden benefits and these are the ones that interest today’s builders of earth shelters.
Earth takes in heat from the sun and stores it so that the dwelling can be warm despite colder temperatures outside. The converse is true in summer and the inside of the dwelling can be cooler.
Ancient earth shelters suffered from drawbacks such as water infiltration and poor internal air quality but the benefits of warmth and safety greatly out-weighed them. Modern earth shelters could have the same difficulty but for every problem an earth shelter creates modern technology produces a solution.
How are Earth Sheltered Houses constructed?
In its simplest terms, modern shelters are usually built into a hillside with only part of the dwelling exposed above ground level. Traditional materials such as reinforced concrete, exposed bricks and various waterproofing systems to the walls and roof are used. The completed structure is covered in excavated earth and usually landscaped. Most dwellings also have their outside surfaces insulated by using polystyrene sheet or by applying an insulating foam covered by foil or similar material.
Ancient men did not have the benefit of these modern products so relied purely on the earth for insulation. Some eco-warriors today do the same when building basic low cost shelters but most take advantage of the range of products and systems available to gain the maximum benefit from their unconventional homes. These would include grey water recycling, wind power turbines, air source heat pumps and solar panels.
Earth shelters are frequently landscaped but this needs to be planned carefully and not just looked upon as a cosmetic finishing-off exercise.
The types of small plants to be installed should have long roots preferably vertical to bind the earth together to help reduce the risk of erosion. Similarly, the character of the trees to be planted near the site should be considered.
Water guzzling trees would be ideal for wet sites but the growth and density of leaves and branches should also be considered particularly if they might screen any solar devices to be installed.