Prefabricated building
Prefabricated building is a type of building that consists of several factory-built units that are assembled on-site to complete the unit.
Prefabricated housing
The term prefabricated building may refer to buildings built in modules (modular homes) or transportable sections (manufactured homes), and may also be used to refer to mobile homes. Although similar in nature, the methods and design of the three can vary wildly. There are two-level home plans, as well as custom home plans.
- Modular homes are homes that are created in sections, and then transported to the home site for construction and installation. These are typically installed and treated like a regular house, for both financing and construction purposes, and are usually the most expensive of the three. Although the sections of the house are prefabricated, the sections, or modules, are put together at the construction much like a typical home.
- Manufactured homes refer to homes that are built onto steel beams, and are transported in complete sections to the home site, where they are assembled.
- Mobile homes are, quite simply, mobile homes; that is, homes built on wheels, that are able to be moved from place to place.
Mobile homes and manufactured homes can be placed in mobile home parks, and manufactured homes can also be placed on private land, providing the land is appropriately zoned for manufactured homes.
Manufactured homes
Constructing manufactured homes typically involves connecting plumbing and electrical lines across the sections, and sealing the sections together. Manufactured homes can be single-, double-, or even triple-wide, which is simply a measure of how many sections wide it is. Many manufactured home companies manufacture a variety of different designs, and many of the floorplans are available online. Manufactured homes can be built onto a permanent foundation, and if designed correctly, can be difficult to distinguish from a stick-built home to the untrained eye.
Manufactured homes are typically purchased from a retail sales company that may be independently owned and operated, initially assembled by a local contracting company, and follow-up repairs performed by the manufactured home company under warranty. For this reason, customer service and reputation are extremely important. Purchasing a manufactured home from a disreputable or dishonest company can lead to lengthy delays in moving, as well as large residual and unexpected costs. For this reason, it is advisable to seek second opinions or first-hand consumer opinions of a manufactured home brand.
A manufactured home, once assembled, goes through a "settling-in" period, where the home will settle into its location. During this period, some drywall cracking may appear, and any incorrectly installed appliances, wiring, and/or plumbing should be repaired, hopefully under warranty. If not covered under warranty, the costs will be borne by the consumer. For this reason, it is important that the consumer ensure that a reputable and honest contractor is used for the initial set-up. If any repairs are not completed by the initial set-up crew, the manufacturer will send repair crews to repair anything covered by the warranty. The secondary repair team must be scheduled, and may not be available immediately for most repairs. Just because a manufactured home has been assembled does not mean it is immediately inhabitable; appropriate ventilation, heating, plumbing, and electrical systems must be installed correctly by the initial set-up crew, otherwise, the consumer must wait until the manufacturer repair team can schedule an appointment, unless the consumer undertakes the repair at personal expense.
Construction sites
Mobile homes and manufactured homes can be placed in mobile home parks, and manufactured homes can also be placed on private land, providing the land is appropriately zoned for manufactured homes. Many cities have not updated zoning regulations for modern manufactured houses, and thus, may not permit manufactured houses to be placed in certain areas.
McDonalds use prefabricated structures for their buildings, and recently set a record of constructing a building and opening for business within 13 hours (on pre-prepared ground works) [1].
'Prefabs'
Prefabricated homes were first produced during the Gold Rush in the United States, when kits were produced in order to enable Californian prospectors to quickly and effectively construct living accommodation [2]. Homes were available in kit form by mail order in the United States in 1908 [3].
Prefabricated housing became increasingly popular during World War II. The United States used Quonset huts as military buildings, and in the United Kingdom, 'prefabs' were built after the war as a means of quickly and cheaply providing quality housing as a replacement for the housing stock destroyed during the war. The proliferation of prefabricated housing across the country was a result of the Burt Committee and the Housing (Temporary Accommodation) Act 1944. Whole estates of prefabs were constructed to provide accommodation for those made homeless by the War and ongoing slum clearance [4]. Almost 160,000 had been built in the UK by 1948 at a cost of close to £216 million.
Prefabs were aimed at families, and typically had an entrance hall, two bedrooms (parents and children), a bathroom (a room with a bath) — which was a novel innovation for many British at that time, a separate toilet, a living room and an equipped (not fitted in the modern sense) kitchen. Construction materials included steel, aluminium, timber or asbestos, depending on the type of dwelling. The aluminium Type B2 prefab was produced as four pre-assembled sections which could be transported by lorry anywhere in the country [5].
The United States also used prefabricated housing, both to provide accommodation for its troops during the War, and for GIs returning home afterwards. Prefab classrooms were also popular with UK schools increasing their rolls during the baby boom of the 1950s and 1960s.
Many of the buildings were designed with a 5-10 year life span, but far exceeded this, with a number surviving today. In 2002, for example, the city of Bristol still had residents living in 700 examples [6]. Many UK councils are beginning to demolish the last surviving examples of World War II prefabs in order to comply with the UK government's Decent Homes Standard, due to come into effect by 2010. However, there has been a recent revival in prefabricated methods of construction in order to compensate for the United Kingdom's current housing shortage [7].