Mass Appeal

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

As a result, tire dealers pay haulers anywhere from 25-to-50¢ a tire to remove them to a stockpile area where they are stacked for an indefinite period of time. An alternative is to shred, which cures their inclination toward resurrection but is also costly. It is no surprise then that most tire dealers welcome any suggestion that would rid them of the used tires in an economical way. If people want to build houses with them, that's just fine.

In Reynolds's houses, the tires are layered in staggered courses similar to bricks. Each tire is put into place empty and then filled with dirt from the excavation. The loose dirt is pounded into the tire rim and more dirt successively is added until the tire is rock solid and all but immovable. The fact that tires come in different sizes adds to their appeal as a building material. The base of the wall is laid with No. 16s, the body with No. 15s, tapering off at the top with No. 14s. Each wall averages about three feet thick, with a finish coat of plaster or adobe.

The unusual thickness of the walls allows for a wide distribution of the weight actually reaching the ground. This qualifies them as structural bearing walls, and their width eliminates the need for additional footings or foundations. In fact, to prove how much weight these tire walls are capable of supporting, Reynolds drove a filled cement mixer on top of one wall. The exposed tires did not even compress under the weight.

Of course, before beginning construction in any new location, local building codes must be satisfied. Reynolds has had engineers examine the walls and testify that they meet and even surpass any existing codes. One engineer claimed that the tire-construction system would be suitable for a dam.

Getting to Know U

To make the most of the mass, the tire walls are layered in U-shapes or modules. Each Earthship is comprised of a series of these U-modules placed side by side, stepped back and above the other, or in a combined layout. The stepped-back approach is most suitable when building up a mountain or on a large hillside.

The most common is the side-by-side configuration. In each case, the object is to make every room a battery. The open end of the U faces south, which allows the sun to warm the interior. Access between rooms is best arranged through a common hallway along the south wall. This maintains the integrity of the mass walls of the U-modules. Any mass that is removed by adding a doorway or window diminishes the efficiency of the battery effect.

While a U can be as small as the builder wants, there are restrictions on how large it can be. The maximum span between the legs of the U should not exceed 18 feet. A larger span would require roof beams that would be too large to be manageable. A U should also not be deeper than 26 feet to efficiently utilize the mass of the walls. If the total area exceeds 18-by-26 feet, there will not be enough mass to heat the resulting volume of air.

RSS | Comments | E-mail | Print