Each year, nearly 300 million tires are disposed of in the U.S. alone. The EPA estimates that markets exist for approximately 80 percent of those tires, leaving an estimated 60 million scrap tires to be stockpiled or landfilled.
Luckily, the market for scrap tires continues to increase. Whether used as fuel, ground and recycled into new products, retreaded or used in civil engineering projects, their rate of recycling and reuse continues to climb.
One such method of reuse is beginning to gain popularity among eco-friendly builders: building with tires.
As the name suggests, the primary material used in rammed-earth construction is, well, compacted earth. We’ve used sand, clay and other compacted soils for centuries in building, from Jericho, the oldest recorded city in history, to the modern day architecture of Frank Lloyd Wright.
Rammed-earth homes are designed to maximize energy-efficiency, remaining relatively warm in winter months and cool in summer months.
Their dense design is ideal for thermal mass storage and their orientation is meant to capture lower winter sun rays and block more direct summer rays.
Recycled automotive tires filled with compacted earth form what are called rammed-earth bricks and are used in place of traditional wood framing. Soil is tightly packed into the frame of the tire, with a cardboard sheet placed across the base. A typical 2,000 square-foot home uses 1,000 scrap tires on average.
Small gaps in the frames, due to the tires being round, are filled with recycled materials, typically aluminum cans or bottles and adobe.
An alternative to rammed-earth tire bricks, tire-bales have been used recently as a way of utilizing scrap resources without the intense labor of packing 1,000 tire bricks.
A tire-bale is a square brick of approximately 100 compressed tires, weighing about 2,000 pounds. Homes built with tire bales use thousands of compressed tires, many more than standard rammed-earth bricks.
They are stacked like oversize bricks to frame the outside walls of the home.
After the walls of rammed-earth and tire-bale walls are smoothed with earth, they are finished with layers of plaster or stucco.
It may be an automatic assumption that homes made of tires, which are highly flammable, would pose serious fire risks. Because the tires are sealed within thick walls, they are not reacting with oxygen. The layer of plaster covering the tires also provides additional fire resistance. The buildings meet and often exceed fire requirements.
This article is part of Earth911.com’s Building With series.