The use of tyres as a tool for construction is just the next step in the evolution of the wheel. Tyres have long been a menace to dispose of off since they are not biodegradable, they are big and are everywhere. In America alone there are 300 million tyres disposed every year, out of those 20%, or 60 million do not have any market, they are stockpiled or end up in landfills. The use of tyres as building materials solves two problems at once, disposing some of the 60 million tyres, and reducing the environmental and financial impact of building a home.
The basis for the use of tyres as construction material was its quality as a heat conductor. In fast moving vehicles, such as race cars, tyres may actually conduct/ transmit enough heat to spontaneously combust. When used as a foundation for homes, tyres act as heat sinks. This simply means that they transfer heat from high temperature to a lower temperature. Heat is removed from inside the house to underground. This is especially useful in tropical climates. There are two alternatives on how to use tyres in construction. The first method is Rammed Earth Construction and the other is Tire Bale Construction.
Rammed Earth Construction
In this method, recycled tyres are filled with compact soil to form what is referred to as rammed-earth bricks which replace traditional wood framing used in most American households. From the time of the Romans to modern sky scrapers soil has been the main building material whether clay or sand. The main aim of using soil for construction is to ensure energy efficiency by conserving heat in winter and remaining cool during the summer. In rammed earth construction tyres soil is packed tightly into the tyre frame using a cardboard sheet on the bottom.
Typically, a 4,000-square foot house can use 2,000 tyres. In Earth ships, the gaps in the frames due to the cyclical shape of the tyres are filled with other recyclable materials like glass/plastic bottles or aluminium cans. Earth ships are a concept first developed by Michael Reynolds in 1970 where houses are made using only recycled and naturally occurring materials. The idea has taken off in recent years with a lot of people looking to build earth ships as second homes.
Tire Bale Construction
Tire bales are used an alternative way to utilize tyres as a recyclable construction resource without the labour-intensive process of packing 2,000 tire bricks. A tire bale consists of about 100 compacted tyres made into a square brick. It weighs approximately 900 kilograms. Construction using tire bales utilizes thousands of these compacted tyres, a lot more than the rammed-earth method. The tire bales frame the outside walls of the house stacked like bricks to cover the whole house.
The walls of either method is smoothed over with cement then layers of plaster or stucco are added to finish.
Tire Building Codes
The tire building codes provide the baseline for determining whether a building built from tires is safe. It is for both the builder and the inspectors to ensure a good construction. The walls of these buildings are the only unorthodox aspects of these buildings and thus covered by these codes. The roof and floors are covered in the uniform building code.
These are some of the highlights of the construction code for building using tyres.
1. Tires 13 inches in diameter are the smallest tires that can be used while 16 inches are the largest.
2. The first layer of tires must be larger in diameter than all the tires making up the wall. No tire in the wall should be larger in diameter than the tires in the wall. Walls over six layers should have ground tires with larger than 15 inches’ diameter.
3. All load bearing walls eight layers or higher built with earth rammed tyres should have a continuous bond beam to connect adjacent non-load bearing tire walls.
4. Every opening in earth rammed tire walls should have concrete half blocks on each side of the opening.
5. Earth rammed tire structures over two stories should be designed by a licensed architect.
6. Earth rammed tire walls are not sensitive to expansion/ contraction of cracks hence no limit is placed on the length of the walls
7. Earth rammed tire walls which form an integral part of the house have a maximum set height of 10 feet.
8. Joints and connections in tyre built walls should have overlapped tyres and connection methods in order to avoid overlapping of stacked joints.
They are only guidelines right now and are still subject to evolution or amendment since it is still a new method of construction. More guidelines can be found on Earth ship Volume I and II.
Advantages of Tyre Construction
There are numerous advantages of construction using recycled tyres. The main advantage obviously is that this method is very cheap or in some cases free. This greatly reduces the cost of owning a home in these economic times. It is good for the environment. Utilizing tyres that would have eventually ended up as waste materials goes a long way in waste management and environmental conservation. Buildings constructed using tyres also conserve and increase energy efficiency by providing high levels of thermal mass without destroying the environment. There is minimal waste material in the construction process and these materials may be utilized in the construction when constructing earth ships. Tyres are strong and durable making the buildings constructed disaster resistant, particularly for weather emergencies.
Disadvantages of Tyre Constructions
Building with tyres is a very labor intensive process with very heavy bricks to carry during construction. Old tires do indeed give off the gas but they need to be exposed to light in order to be broken down. In tire bales constructions, the tires are covered by stucco or plaster hence not exposed and no gas is emitted. Tyres are highly flammable but the structures built are not prone to fire risks since they have thick walls and a plaster layer cutting off oxygen and providing fire resistance. It is evident that there are little drawbacks to using tyres in your construction.
By reusing tyres which would have been a waste as materials for construction and the resulting decrease in artificial energy consumption, the strain to the environment is reduced while providing a comfortable and affordable home.