Modular buildings and modular homes are sectional prefabricated buildings, or
houses, that consist of multiple sections called modules. "Modular" is a
method of construction differing from other methods. The modules are six sided
boxes constructed in an exterior facility, then delivered to their
intended site of use. Using a crane, the modules are set onto the building's
foundation and joined together to make a single building. The modules can be
placed side-by-side, end-to-end, or stacked, allowing a wide variety of
configurations and styles in the building layout.
Modular buildings, also called prefabricated buildings, differ from
mobile homes, which are also called manufactured homes, in two ways. First,
modular homes do not have axles or a frame, meaning that they are typically
transported to their site by means of flat-bed trucks. Secondly, modular
buildings must conform to all local building codes for their proposed use,
while mobile homes, made in the United States, are required to conform to
federal codes governed by HUD. There are some residential modular buildings that
are built on a steel frame that do meet local building codes and are considered
modular homes, rather than mobile homes. Uses
Modular buildings may be used for long-term, temporary or permanent
facilities, such as construction camps, schools and classrooms, civilian and
military housing, and industrial facilities. Modular buildings are used
in remote and rural areas where conventional construction may not be
reasonable or possible, for example, the Halley VI accommodation pods used for a
BAS Antarctic expedition. Other uses have included churches, health care
facilities, sales and retail offices, fast food restaurants and cruise ship
construction. They can also be used in areas that have weather concerns, such
as hurricanes. Construction process
Modular components are typically constructed indoors on assembly lines.
Modules' construction may take as little as ten days but more often one to three
months. Completed modules are transported to the building site and
assembled by a crane. Placement of the modules may take from several hours to
several days. Manufacturing considerations
The entire process of modular construction places significance on the
design stage. This is where practices such as Design for Manufacture and
Assembly are used to ensure that assembly tolerances are controlled
throughout manufacture and assembly on site. It is vital that there is enough
allowance in the design to allow the assembly to take up any "slack" or
misalignment of components. The use of advanced CAD systems, 3D printing and
manufacturing control systems are important for modular construction to be
successful. This is quite unlike on-site construction where the tradesman can
often make the part to suit any particular installation.
Advantages Modular buildings are argued to have
advantages over conventional buildings, for a variety of reasons.
Speed of construction/faster return on investment. Modular construction allows
for the building and the site work to be completed simultaneously. According to
some materials, this can reduce the overall completion schedule by as much
as 50%. Indoor construction. Assembly is
independent of weather, which can increase work efficiency and avoids
damaged building material. Ability to service remote locations.
Particularly in countries in which potential markets may be located far
from industrial centers, 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. 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, construction of a modular
dwelling generates much less waste. Environmentally friendly construction
process. Modular construction reduces waste and site disturbance compared to
site-built structures. Flexibility. One can continually add to
a modular building, including creating high rises.
Disadvantages Volumetric: Transporting the completed
modular building sections take up a lot of space.
Flexibility: Due to transport and sometimes manufacturing restrictions,
module size can be limited, affecting room sizes.
Modular homes may lose their value quickly.
Some financial institutions may be hesitant to offer a loan for a modular
home. = 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 and Australia, modular homes have become accepted in some regional areas;
however, they are not commonly built in major cities. Recent innovations allow
modular buildings to be indistinguishable from site-built
structures. Surveys have shown that individuals can rarely tell the
difference between a modular home and a site-built home.
= Modular homes vs. mobile homes= Differences include the building codes
that govern the construction, types of material used and how they are appraised
by banks for lending purposes. The codes that govern the construction of modular
homes are exactly the same codes that govern the construction of
site-constructed homes. In the United States, all modular homes are
constructed according to the International Building Code, IRC, BOCA
or the code that has been adopted by the local jurisdiction.
= Recognizing a mobile or manufactured home=
A mobile home should have a small metal tag on the outside of each section. If
you cannot locate a tag, you should be able to find details about the home in
the electrical panel box. This tag should also reveal a manufacturing date.
Modular homes do not have metal tags on the outside but will have a dataplate
installed inside the home, usually under the kitchen sink or in a closet. The
dataplate will provide information such as the manufacturer, third party
inspection agency, appliance information, and manufacture date.
= Materials= The materials used in modular homes are
the same as site constructed homes. Wood-frame floors, walls and roof are
the most typical. Some modular homes include brick or stone exteriors,
granite counters and steeply pitched roofs. All modulars are designed to sit
on a perimeter foundation or basement. In contrast, mobile homes are
constructed with a steel chassis that is integral to the integrity of the floor
system. Mobile homes often require special lenders. Most companies have
standard plans. However, all modular buildings can be custom built to a
client's specifications. Today's designs include multi-story units, multi-family
units and entire apartment complexes. The negative stereotype commonly
associated with mobile homes has prompted some manufacturers to start
using the term "off-site construction." Standards and zoning considerations
Typically, modular dwellings are built to local, state or council code,
resulting in dwellings from a given manufacturing facility having differing
construction standards depending on the final destination of the modules. For
example, homes built for final assembly in a hurricane-prone, earthquake or
flooding area may include additional bracing to meet local building codes.
Steel and/or wood framing are common options for building a modular home.
Some US courts have ruled that zoning restrictions applicable to mobile homes
do not apply to modular homes since modular homes are designed to have a
permanent foundation. Additionally, in the US, valuation differences between
modular homes and site-built homes are often negligible in real estate
appraisal practice; modular homes can, in some market areas, be evaluated the
same way as site-built dwellings of similar quality. In Australia,
manufactured home parks are governed by additional legislation that does not
apply to 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. = Building strength=
Modular homes are designed to be stronger than traditional homes by, for
example, replacing nails with screws, adding glue to joints, and using 10-20%
more lumber than conventional housing. This is to help the modules maintain
their structural integrity as they are transported on trucks to the
construction site; however, it is difficult to predict the final building
strength since the modules need 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.
= CE marking= The CE mark is a construction norm that
guarantees the user of mechanical resistance and strength of the
structure. It is a label given by European community empowered authorities
for end-to-end process mastering and traceability.
All manufacturing operations are being monitored and recorded:
Suppliers have to be known and certified,
Raw materials and goods being sourced are to be recorded by batch used,
Elementary products are recorded and their quality is monitored,
Assembly quality is managed and assessed on a step by step basis,
When a modular unit is finished, a whole set of tests are performed and if
quality standards are met, a unique number and EC stamp is attached to and
on the unit. This ID and all the details are recorded
in a database, At any time, the producer has to be able to answer and provide all
the information from each step of the production of a single unit, The EC
certification guaranties standards in terms of durability, resistance against
wind and earthquakes. = Surfaces and finishes=
Modular buildings can be assembled on top of multiple foundation surfaces,
such as a crawl space, stilts, full basements or standard slab at 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 to
which a modular structure can be built depends on jurisdiction, but a number of
countries, especially in Asia, allow them to be built to 24 floors or 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 applied in the field after the basic
installation is completed. = U.S. regional differences with modular
construction= Weather, population density,
geographical distances, and local housing architecture play a role in the
use of modular construction for home building. Because modular construction
is so adaptable, it has begun to permeate every region of the U.S.
Northeast The northeast is populated with
factories that can combine modular housing design with other construction
methods such as panelization and SIPs. Modules are typically limited to 16'
width and up to 70' lengths because of the narrow road structure and densely
populated areas of the region. Other limitations are placed on transportation
to locations such as Connecticut, Cape Cod, and Long Island.
Mid-Atlantic The Mid-Atlantic region is similar to
the northeast, in terms of building design and transport restriction to
modules to a width of not more than 16'. Southeast
Manufacturers in the Southeast often limit their ability to customize homes
and focus on very traditional single story floor plans. Much of the south is
in coastal and high wind areas; modular construction may prove appealing in this
area as it is already inherently stronger as it must be built for
transport and craned installation, therefore offering wind resistance as
good or higher than site-built construction.
Central Plains The central plains states typically are
made up of farming and rural communities. Ranch homes are the
mainstay of the region. Prone to strong storms and tornado conditions, modular
construction offers the ability to better withstand these storm patterns
than its site built counterpart. The inter-module attachments that must be
made when assembling a modular home on a foundation offer an inherently stronger
home than site built construction can offer. Interior finishes on both the
walls and ceilings are typically textured. Corners on interior walls are
typically rounded and finish trim around windows is optional. Because of the
wider road and lower population density, modules can be as wide as 20' and as
long as 90'. The ability to provide larger modules reduces the amount of
modules needed to complete a home. Rockies
Home design in this area ranges from Chalet style homes to log cabin style
homes. Manufacturers in the region therefore provide a number of styles of
homes. Capability varies from factory to factory as well as the ability to do
complete customization of floor plans. Transportation is limited mostly to 16'
wide modules to travel the roads of the area.
West Coast The high cost of living in coastal
areas, and especially California, may provide modular construction an edge due
to its lower cost. Extreme building regulation and environmental
requirements can delay the start of residential construction. Several
factories specialize in environmentally responsible construction by following
green construction standards and offering zero energy homes.
Living in coastal areas also mean that the modular home structure should be
strong enough to withstand winds with high velocity. Modular homes, built
correctly, have such kind of resistance to stand high wind velocity without any
damage issues. Research and Development
Modular construction is the subject of continued research and development
worldwide as the technology is applied to taller and taller buildings. Research
and development is carried out by modular building companies and also
research institutes such as the Modular Building Institute and the Steel
Construction Institute,. Open modular building
Modular building can also be open source and green.
3D printing can be used to build the house.
The main standard is OpenStructures and its derivative Autarkytecture.
See also 3D printing
Container home Kit house
MAN steel house Manufactured housing
Modular design NTA Inc
Open-source architecture Open source hardware
OpenStructures Prefabricated home
Stick-built home Toter
References External links
Modular Construction in Pictures An example of a modular construction
project from start to finish described in photographs of the process.
Modular Building Systems Association – National trade association representing
the legislative and regulatory interests of the modular housing industry
National Association of Home Builders National Modular Housing Council
National Trade Association for the Modular Housing Industry
Modular Building Institute – International trade association
representing non residential modular construction professionals
The Modular and Portable Building Association The Modular and Portable
Building Association is the trade association representing and promoting
the use of temporary modular buildings or permanent modular buildings in the
United Kingdom A Timelapse of a modular build