Mobile homes or static caravans are prefabricated homes built in factories, rather than on site, and then taken to the place where they will be occupied. They are usually transported by tractor-trailers over public roads to sites which are often in rural areas or high-density developments. In some countries they are used for temporary accommodation on campsites. While these houses are usually placed in one location and left there permanently, they do retain the ability to be moved as this is a requirement in many areas. Behind the cosmetic work fitted at installation to hide the base, there are strong trailer frames, axles, wheels and tow-hitches. The two major sizes are single-wides and double-wides. Single-wides are eighteen feet or less in width and 90 feet or less in length and can be towed to their site as a single unit. Double-wides are twenty feet or more wide and are 90 feet in length or less and are towed to their site in two separate units, which are then joined together. Triple-wides and even homes with four, five, or more units are also built, although not as commonly. Mobile homes are less expensive per square foot than site-built homes.
This form of housing goes back to the early years of cars and motorized highway travel. It was derived from the travel trailer, a small unit with permanently attached wheels often used for camping. Larger units intended to be used as dwellings for several months or more in one location came to be known as house trailers.
The original focus of this form of housing was its mobility. Units were initially marketed primarily to people whose lifestyle required mobility. However, beginning in the 1950s, the homes began to be marketed primarily as an inexpensive form of housing designed to be set up and left in a location for long periods of time, or even permanently installed with a masonry foundation. Previously, units had been eight feet or less in width, but in 1956, the 10-foot (3.048 metre) wide home ("ten-wide") was introduced, along with the new term "mobile home." The homes acquired a rectangular look, made from pre-painted aluminum panels, rather than the streamlined look of travel trailers, which were usually painted after assembly. All of this helped solidify the line between these homes and house/travel trailers. The smaller units could be moved simply with a car, but the larger, wider units usually required the services of a professional trucking company, and, often, a special moving permit from a state highway department. In the 1960s and '70s, the homes became even longer and wider, making the mobility of the units more difficult. Today, when a factory built home is moved to a location, it is usually kept there permanently and the mobility of the units has considerably decreased.
Many people who could not afford a traditional site-built home or did not desire to commit to spending a large sum of money on housing began to see this factory built homes as a viable alternative for long-term housing needs. The units were often marketed as an alternative to the apartment rental. However, the tendency of the units of this era to rapidly depreciate in resale value made using them as collateral for loans far riskier than traditional home loans. Terms were usually limited to less than the thirty year term typical of the general home-loan market, and interest rates were considerably higher. In other words, home loans resembled motor vehicle loans far more than traditional home mortgages.
The rise of the factory built homes brought with it complications the legal system was not prepared to handle. Originally, factory built homes tended to be taxed as vehicles rather than real estate, which resulted in very low property tax rates for their inhabitants. This led local governments to reclassify them for taxation purposes.
However, even with this change, rapid depreciation often resulted in the home occupants paying far less in property taxes than had been anticipated and budgeted. The ability to move many factory built homes rapidly into a relatively small area resulted in strains to the infrastructure and governmental services of the affected areas, such as inadequate water pressure and sewage disposal, and highway congestion. This led jurisdictions to begin placing limitations on the size and density of developments.
As noted above, early homes, even those that were well-maintained, tended to depreciate in value over time, much like motor vehicles, rather than appreciate in value, as with site-built homes. The arrival of these homes in an area tended to be regarded with alarm, in part because of devaluation of the housing potentially spreading to preexisting structures.
This combination of factors has led most jurisdictions to place zoning regulations on the areas in which factory built homes are placed, and limitations on the number and density of homes permitted on any given site. Other restrictions, such as minimum size requirements, limitations on exterior colors and finishes, and foundation mandates have also been enacted. There are many jurisdictions that will not allow the placement of any additional factory built homes. Others have strongly limited or forbidden all single-wide models, which tend to depreciate in value more rapidly than modern double-wide models.
Apart from all the practical issues described above, there is also the constant discussion about legal fixture and chattels - meaning that the legal status of a trailer is, or could be, affected by its incorporation to the land or not. This sometimes involves such factors as whether or not the wheels have been removed.
Newer homes, particularly double-wides, tend to be built to much higher standards than their predecessors and meet the building codes applicable to most areas. This has led to a reduction in the rate of value depreciation of most used units.
Additionally, modern homes tend to be built from materials similar to those used in site-built homes rather than inferior, lighter-weight materials. They are also more likely to physically resemble site-built homes. Often, the primary differentiation in appearance is that factory built homes tend to have less of a roof slope so that they can be readily transported underneath bridges and overpasses.
The number of double-wide units sold exceeds the number of single-wides, which is due in part to the aforementioned zoning restrictions. Another reason for higher sales is the spaciousness of double-wide units, which are now comparable to site-built homes. Single-wide units are still popular primarily in rural areas, where there are fewer restrictions. They are frequently used as temporary housing in areas affected by natural disasters, when restrictions are temporarily waived.
Modular built homes are transported on flatbed trucks rather than being towed, and lack axles and an automotive-type frame. However, some of these houses are towed behind a semi-truck on a frame similar to that of a trailer. The house is usually in two pieces and is hauled by two separate trucks. Each frame has five or more axles, depending on the size of the house. Once the house has reached its location, the axles and the tongue of the frame are then removed, and the house is set on a concrete foundation by a large crane.
Both styles are commonly referred to as factory built housing, although its technical use is restricted to a class of homes regulated by the Federal National Mfd. Housing Construction and Safety Standards Act of 1974.
Most zoning restrictions on the homes have been found to be inapplicable or only applicable to modular homes. This occurs often after considerable litigation on the topic by affected jurisdictions and by plaintiffs failing to ascertain the difference. Most modern modulars, once fully assembled, are indistinguishable from site-built homes. Their roofs are usually transported as separate units. Newer modulars also come with roofs than can be raised during the setting process with cranes. There are also modulars with 2 or 3 stories. As the legal differentiation between the two becomes more codified, the market for modular homes is likely to grow.
The traditional home industry would seem to have a bright future as well. As the demand for housing continues to grow, the price of housing continues to increase rapidly. The quality and features of these homes has led to greater acceptance by a growing segment of the marketplace. Additionally, insurers and lenders are now more likely to treat the higher-end factory built home as they would a traditional home.
Tornadoes do not actually strike factory built homes any more or less frequently than any other type of structure. However, while an F1 tornado might cause minor damage to a site-built home, it could do significant damage to a factory built home, especially an older model or one that is not properly secured. Many brands offer optional hurricane straps, which can be used to tie the home to anchors embedded in the ground.
In the United Kingdom there are two main types of caravans: touring caravans and static caravans. A touring caravan is towed behind a car to its site and parked, often for only a brief period. Touring caravans are usually no larger than 8' wide and can have 1 or 2 axles (2 or 4 wheels respectively). Static caravans aren't towed, as they are too large to tow and have a rudimentary chassis with no suspension or brakes, and therefore are transported on the back of large flatbed lorries. The axle and wheels are used for movement to the final location when the static caravan is moved by tractor or 4x4. A static caravan will normally stay on a single plot for many years, and have many of the modern conveniences one would normally find in a home.
Static holiday caravans generally have sleeping accommodation for 6 to 8 people in 2 to 3 bedrooms and on convertible seating in the lounge. They tend towards a fairly "open-plan" layout, and while some units are insulated and centrally heated for year-round use, cheaper models without double glazing or central heating are available for mainly summer use. Holiday homes are intended for leisure use and are available in 10'and 12' widths, a small number in 13' and 14' widths, and a few 16' wide, consisting of two 8' wide units joined together. Generally holiday homes are clad in painted steel panels. Static caravans are sited on caravan parks where the owner of the site leases a plot to the caravan owner. Many of these parks are sited in areas that are prone to flooding and anyone considering buying a sited static caravan needs to take particular care in checking that their site is not liable to flooding. Some park owners used to have unfair conditions in their lease contracts but the Office of Fair Trading has produced a guidance document available for down load called Unfair Terms in Holiday Caravan Agreements which aims to stop unfair practices.
In 2005, a neighborhood of about 500 homes was established in Nitzan. This was a temporary community set up north of Ashkelon, Israel, to house those evicted from their homes in Gush Katif as part of Israel's unilateral disengagement plan.
These homes were named caravillas (Hebrew: קרווילה), which is a portmanteau of the words caravan, and villa. The building is composed of several prefabricated sections that are joined on a foundation. This is akin to the Israeli concept of a villa, or single-family home. The caravilla is more spacious than a regular factory built home, and was instrumental in pacifying objections to the disengagement plan.