• Shipping containers can be modified and combined to create housing units.container ship express image by feisty from Fotolia.com
  
  A freight container, also called a shipping container, is a large steel crate used to store goods being transported. Usually, these containers are moved via railway, truck or ship. Standard containers are either 20 or 40 feet in length and are strong. Residences created using recycled shipping containers are called "container houses."
  
  

Insulation

• Shipping containers are made from steel, which is a good conductor of heat. This means that in a container home, heat is lost quickly. In order to compensate for this heat loss, large amounts of insulation is needed.
  
  Adding insulation to a container house can be a problem. In a traditional home, space exists between the interior and exterior walls. This space typically contains insulating material. A shipping container, however, has only one metal wall, with no space for insulation. To solve this problem, additional interior walls must be added or insulation must be hung directly on the metal walls of the structure.
  
  

Zoning

• In many residential areas, zoning rules restrict the types of homes that can be constructed. Steel homes, particularly those created from shipping containers, are not commonly built in these neighborhoods. This can cause problems when applying for a building permit within residential zoning.
  
  Because using containers for housing is a relatively new concept, many people are not familiar with their designs. As a result, neighborhood residents and approval boards may resist the construction of a container design.
  
  

Contaminants

• One of the purposes of using shipping containers as a building material is to re-use and recycle scrap units. However, because these units have held many different types of contents in the past, contaminants may be left over. These contaminants can include chemicals, fumes and toxic paints.
  
  For this reason, containers must be thoroughly stripped and cleaned before being used for housing. While this procedure is normally not difficult, it is time consuming. This extra steps increases the overall time period, and the cost, of building a container home.
  
  

Rust

• The steel material used to construct shipping containers is designed to be weather resistant. However, any metal containing amounts of iron will begin to rust under certain conditions, and steel is no exception.
  
  Because container houses often make use of older recycled container units, rust can be a major concern. Moisture, rain and snow can combine to accelerate the rust process, leading to holes in the walls and floor. More important, rust can cause the structure of a container house to fail, causing it to become unsafe.
  
  

Space

• Once completed, a shipping container home does not take up much space. During construction, however, a significant amount of free space is needed. First, enough space must be available at the building site for the containers to be delivered and placed. Containers must be moved using cranes and other heavy equipment, which must have room to maneuver and move.
  
  Second, modification of shipping containers requires free space around the construction area. As steel is cut and containers are connected, workers must have ample space to operate welders, torches and other tools.