Modular home

Modular homes are houses that are divided into multiple modules or sections which are manufactured in a remote facility and then delivered to their intended site of use. The modules are assembled into a single residential building using either a crane or trucks.

Typically, modular dwellings are built to local state or council code, so dwellings built in a given manufacturing facility will have differing construction standards depending on the final destination of the modules [cite web|url=http://www.austlii.edu.au/au/legis/nsw/repealed_reg/lgheamhr1995693/ |title=Australian Government modular home regulations |accessdate=2007-10-21] . Steel and/or wood framing are common options for building a modular homes. Modular home designs can be customized for local zoning codes. For example, homes built for final assembly in a hurricane prone area can have additional bracing built-in to meet local building codes.

Modular components are typically constructed within a large indoor facility on assembly lines much like Henry Ford originally instituted with his automobile company. Such facilities use an assembly line track to move the modules from one workstation to the next. Independent building inspectors are on site to supervise the construction and ensure that all building codes are adhered to during assembly. Such dwellings are often priced lower than their site-built counterparts and are typically more cost-effective to builders and consumers. These new homes can be constructed in less time then it takes to build a home "on-site". [cite web|url=http://www.bobvila.com/HowTo_Library/Modular_Homes_Make_Sense-Building_Systems-A1854.html |title=Modular homes make sense |accessdate=2007-07-12] Manufacturers cite the following reasons for the typically lower cost/price of these dwellings:

*Indoor construction. Assembly is independent of weather which increases work efficiency and avoids damaged building material.
*Favorable pricing from suppliers. Large-scale manufacturers can effectively bargain with suppliers for discounts on materials.
*Ability to service remote locations. Particularly in countries such as Australia there can be much higher costs to build a site-built house in a remote area or an area experiencing a construction boom such as mining towns. Modular homes can be built in major towns and sold to regional areas. [cite web|url=http://au.messages.yahoo.com/news/localnews-qld/603/ |title=Mining boom housing shortage |accessdate=2007-10-21]
*Low waste. With the same plans being constantly built, the manufacturer has records of exactly what quantity of materials are needed for a given job. While waste from a site-built dwelling may typically fill several large dumpsters, waste from a modular dwelling generates much less waste. [cite web|url=http://www.housingzone.com/probuilder/article/CA6349844.html |title=Modular and Green |accessdate=2006-09-15]

Off-frame modular dwellings differ from mobile homes largely in their absence of axles or a frame, meaning that they are typically transported to their site by means of flat-bed trucks; however, some modular dwellings are built on a steel frame (on-frame modular), which can be used for transportation to the homesite. Many modular homes are of multi-level design, and are often set in place using a crane.

Building Strength

According to manufacturers, modular homes are generally designed to be initially stronger than traditional homes by, for example, replacing nails with screws and adding glue to joints. This is supposed to help the modules maintain their structural integrity as they are transported on trucks to the construction site. Despite manufacturer claims that the modular home is initially built to be stronger than a traditional home, it is hard to predict the final building strength since it needs to endure transportation stresses that traditional homes never experience.

When FEMA studied the destruction wrought by Hurricane Andrew in Dade County Florida, they concluded that modular and masonry homes fared best compared to other construction. You can see the full report FIA-22, 2/93 at http://www.fema.gov/library/viewRecord.do?id=2765

Typically, a modular home contains about 10% to 20% more lumber compared to traditional stick built homes. This is because modules need to be transported to the job site and the additional lumber helps keep them stable.

Assembly time

The modules that will combine to form the house are assembled off-site in a factory. These modules can take one to three months to be constructed but often take as little as 10 days to actually construct when they are first started. Then they are transported to the building site where a crane is brought in to assemble the modules together. The placement of the modules together generally takes several hours or days. Once assembled, modular buildings are essentially indistinguishable from typical site-built homes. While mobile manufactured buildings often decrease in value over time, a well-built modular should have the same longevity as its site-built counterpart, increasing in value over time.

Zoning considerations

Some US courts have ruled that zoning restrictions applicable to mobile homes do not apply to modular homes since modular homes are often assembled with a permanent foundation. Additionally, in the US, the Uniform Standards of Professional Appraisal Practice allow site-built homes to be used as comparators to modular homes in real estate appraisal; thus, modular homes can in some cities and counties (depending on local ordinances) be evaluated the same way as traditionally built dwellings of similar quality. In Australia Manufactured Home Parks are governed by additional legislation that does not cover permanent modular homes. Possible developments in equivalence between modular and site-built housing types for the purposes of real estate appraisals, financing and zoning may increase the sales of modular homes over time. [cite web|url=http://www.modulartoday.com/modular-building-codes.html |title=Building Codes for Modular Homes |accessdate=2007-07-12]

Green & Prefab

There have been some great advances by designers in California to push prefab housing into green building practices. Michelle Kaufman MK Designs, Nichoel Farris Lime Designs, American Home Sales, are creating and marketing sustainable prefab homes. For more info go to mkd-arc.com and newecohomes.com

Construction surfaces

Modular buildings can be assembled on top of multiple foundation surfaces, such as a crawl space, stilts (for areas that are prone to flooding), full basements or std. slab on grade. They can also be built to multi-story heights. Motels and other multi-family structures have been built using modular construction techniques. The height that a modular structure can be built to depends on jurisdiction but a number of countries, especially in Asia, allow them to be built to 24 floors and possibly even more.

Exterior wall surfaces can be finalized in the plant production process or in the case of brick/stone veneers field applications may be the builders choice. Roof systems also can be apart of - separate from - applied in the field after the basic installation is completed.

Market acceptance

Some home buyers and some lending institutions resist consideration of modular homes as equivalent in value to site-built homes. While the homes themselves may be of equivalent quality, entrenched zoning regulations and psychological marketplace factors may create hurdles for buyers or builders of modular homes and should be considered as part of the decision-making process when exploring this type of home as a living and/or investment option. In the UK & Australia modular homes have become quite accepted in regional areas however are not commonly built in major cities. Some modular building manufacturers have begun to refer to modular buildings as “off-site construction” to combat the negative image of modular which is due to portables or trailer stereotypes. Recent innovations allow modular buildings to be indistinguishable from site built structures. [cite web|url=http://www.modtech.com/ |title=Modular Building Company using Off-site Construction term |accessdate=2008-03-20]

Modular Homes Appreciation

According to Kevin Jewel's 2003 study, the "average appreciation rates of manufactured homes packaged with owned land are statistically in line with the site built market, and there are few inherent reasons that a home built in a factory should perform differently than one built on site. Our analysis suggests that consumers can make decisions which can improve the appreciation of a manufactured home. Land ownership, location, purchase price and maintenance expenditures are among the factors that predict appreciation, and should be considered when attempting to increase appreciation in a particular unit." [cite web|url=http://www.amthomeindustriesltd.com/page/1676330 |title=Modular Homes Appreciation|accessdate=2008-03-13]

Disadvantages compared with site-built houses

Although modular homes tend to be cheaper to build compared to site built homes there are several reasons why modular homes have not become more widely accepted.
*Social stigma. In the past modular homes have been very basic "cardboard box" style buildings with little character. Construction methods and designs have improved however this stigma remains.
*Financing issues. Lenders are less familiar with modular homes and tend to limit the amount of funds released prior to the house being on site. Lenders in Australia for example prefer to lend using the value of the land and release funds for construction only when the house is on site. This creates a cash flow issue for the builder and their customer.
*Council, state & zoning regulations. Additional regulations may apply to modular homes. This varies widely between countries and states.
*Design flexibility. Site-built homes have few limits in the design process. Since a modular home has to be built in sections and transported on a truck the design options are limited. Recently some builders have been adding small site-built additions to modular homes to combat this problem or have invested in technology to allow multiple story construction.
*Site access & suitability. Building sites that can only be accessed via narrow roads, gates or under low overpasses can cause problems for modular home delivery. Recent technological advancements mean that sloping sites are no longer the problem they were in the past.

ee also

*Prefabricated home
*Manufactured housing
*Stick-built home
*Cardinal Industries, Inc.
*Palm Harbor Homes

References

* [http://newecohomes.com Green Prefab Homes] - Affordable and Sustainable factory homes
* [http://www.steelvilla.com "The new web steel Modular home"] - New construction of web steel modular building
* [http://www.modularhousing.com Modular Building Systems Association] - The national trade association representing the legislative and regulatory interests of the modular housing industry.
* [http://www.ntainc.com NTA, Inc. - Modular housing engineering design]
* [http://www.modularhomesnetwork.com/ModularRatings/ratings-guide.asp Free Modular Home Guide] - This free resource guide contains important facts about the modular housing industry.
* [http://www.nahb.org/modular National Association of Home Builders]