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Photograph of this much-modified trailer - this is not a modern mobile home. It was a camper, converted to use as a house, or perhaps an addition to a house.Definition of:
Modular Construction, Mobile Homes, Campers, Double-Wides, Trailers, Pre-Cut Homes, & Panelized Construction

Definitions of modular construction, manufactured housing, mobile homes, trailers, campers, doublewides, panelized construction.

What are the differences and how are these structures recognized? This article describes the history and characteristics of these different types of factory-built structures.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

Definitions: What is a Mobile Home, Trailer, Doublewide, Modular Home, Factory-Built Home, Panelized-Construction-Built Home?

At ARCHITECTURE & BUILDING COMPONENT ID we included US DOE definitions for the following classes of "manufactured homes":

Manufactured Homes

Manufactured homes are those built entirely in a factory. They are then transported to a building site and installed.

A manufactured home (formerly known as a mobile home) is built to the Manufactured Home Construction and Safety Standards (HUD Code) and displays a red certification label on the exterior of each transportable section. Manufactured homes are built in the controlled environment of a manufacturing plant and are transported in one or more sections on a permanent chassis. - US HUD at https://portal.hud.gov/hudportal/HUD?src=/program_offices/housing/rmra/mhs/faqs

A manufactured home is a single-family dwelling built according to the U.S. Department of Housing and Urban Development (HUD) Manufactured Home Construction and Safety Standards Act, which is a national, preemptive building code. - Washington State Government, http://www.lni.wa.gov/TradesLicensing/FAS/Mobile/ (2014)

However the term "manufactured home" is used by different authoritis to include a variety of construction types as we list next.

See MOBILE HOME CODES, STANDARDS & MANUALS for complete details, standards, codes, regulations for manufactured housing & similar constructions

Manufactured homes, in a wider sense include:

Modular Homes

Modules are transported to the site and installed.

See MODULAR HOME CONSTRUCTION for a detailed look at modern modular home construction.

Panelized Homes

Panels—a whole wall with windows, doors, wiring and outside siding—are transported to the site and assembled.

See PANELIZED CONSTRUCTION for a detailed look at a 1950's panelized construction home that was war surplus (Fishkill NY).

Pre-Cut Homes

Building materials are factory-cut to design specifications, transported to the site, and then assembled. Pre-cut homes include kit, dome, and log homes.

LOG HOME GUIDE - provides an example of pre-cut homes, how to inspect, diagnose, and repair problems on log houses; how to identify and determine the age of different types of log homes: traditional log homes, manufactured log homes, slab-sided log homes, and alternative log homes using concrete logs and fiberglass logs.

SEARS KIT HOME IDENTIFICATION provides the most famous example of pre-cut home construction.

Also see KIT HOMES, Aladdin, Sears, Wards, Others

Mobile Homes

This is the term used for factory-built homes produced prior to when the HUD Code went into effect.

A mobile home is a factory-built dwelling built prior to June 15, 1976, to standards other than the HUD Code [cited above] that were acceptable under applicable U.S. State Codes (or equivalent in other countries) in effect at the time of construction or introduction of the home into the state. E.g. U.S. Washington State WAC 296-150-M. - Washington State Government, http://www.lni.wa.gov/TradesLicensing/FAS/Mobile/ (2014)

See MOBILE HOMES, DOUBLEWIDES, TRAILERS for a detailed look at the wide range of quality and condition of these homes.

See MOBILE HOME ELECTRICAL SYSTEMS for examples of differences in building & electrical code requirements depending on the type of construction.

The following is the opinion of the author and has not had a technical review by other industry experts. Various trailer, mobile home, and modular housing manufacturers may disagree with some of these views. Corrections and content suggestions are welcome.

Characteristics of Trailers as Living Space

Tipping trailer home (C) Daniel Friedman

Trailer traditionally describes a usually small, wheeled, home with a history and image of flimsy construction such as wooden 1x3 wall framing clad with aluminum siding, virtually no insulation, and low quality leaky windows.

"Trailers" up until the 1970's (my estimate) included both campers (photo at left) which really were intended to be towed by a car or truck and moved often from site to site (though some were left parked for decades at campgrounds), and also lightweight factory-made homes which were intended to be towed once to a home site and then kept there.

The camper shown in our photo (left) was abandoned but had previously served as a summer camp for many years.

The little blue structure used as an addition to the left of the small house in the photo at the top of this page was undoubtedly a small camper.

No one building "trailers" calls them that any longer because of the "flimsy" image.

Camper Trailer (C) Daniel Friedman

The closest thing to a "trailer" in current products on the market are motor homes and campers such as these campers parked along Wappingers Creek in our photo (left).

The least-costly campers (such as our pickup truck "slide-on camper") built after 2000 are probably considerably better constructed than the "trailers" of old. In current language (2009), a "trailer" is either a "mobile home" that is more than 20 years old (see below), or it is a camper designed to be moved easily and often from site to site.

(Or in different usage, a "utility trailer" is a utility vehicle intended to haul goods or large items and designed to be fastened to the back of a car or truck, and a "tractor trailer" is of course a larger (typically 40 ft long) hauling system for moving goods by highway from city to city.)

Trailers may have had their wheels left on, but normally they'd be set on a masonry pier foundation and a skirt installed around to hide the under-trailer area.

Characteristics of Mobile Homes as Living Space

Mobile home with bad roof (C) Daniel Friedman

In the past few decades (to 2006), "trailer" manufacturers have considerably improved the quality of construction of such homes. The national manufacturing and building code standards for these structures have also been improved.

Perhaps in part to escape the less than wholesome image of "trailer", manufacturers use the term "mobile home" to describe what is usually larger and better made home than "trailers" of old, though perhaps with similar materials.

Mobile homes are built in a factory and are designed to be moved (once and uncommonly, perhaps once again) on its own wheels attached to its own frame to a site where a foundation is prepared and connections to utilities are made.

In the U.S., states have regulations about the siting, foundation, steps and entry, wiring, plumbing, tie-downs for wind and storm safety that apply to these homes. Some examples of mobile home regulations for New York State are this website. Individual state regulations will vary - you'll want to see what your state requires. Even within states regulations vary as wind and weather conditions do also.

Examples of mobile home improvements include stronger overall wall and roof construction, less leaky roof covering, and windows that are less notoriously leaky. In addition newer mobile homes have, for fire safety, bedroom windows that can be pushed out to a wide opening for emergency exit in case of fire - an important safety improvement.

Usually building departments grandfather in older structures, but sometimes they will insist that certain life-safety improvements be made, for example if an older mobile home is being brought to a new site in a new community. If this is the case one or two windows may need to be replaced to provide this important safety improvement.

When there is a severe storm or hurricane, mobile home communities are among the worst damaged as a strong wind can completely turn over or demolish mobile homes. For this reason, mobile homes set up in high wind-risk zones have extra requirements for tie-downs to secure the building against upset during a storm.

Mobile homes may arrive on wheels but they will be jacked enough to be set on some type of approved building foundation, such as masonry piers or a masonry foundation.

In case these terms are not confusing enough, some mobile home makers like to call these "factory built homes". But that use of "factory-built homes" is confusing too since modular homes are also "factory built" but are quite different from trailers or mobile homes.

Characteristics of a "Doublewide" Mobile Home or Trailer

Some manufacturers provide mobile homes constructed to be joined together, side by side to form a double-width living unit.

While a double-wide mobile home is basically constructed by the same materials and methods just described above, the tie-down and connection requirements for these living units may be different in some jurisdictions, since their risk of being blown away in high winds is different.

Other installation and support requirements, such as connection of the two units and placement of foundation support will also have to accommodate this variation.

Modular home construction and inspection are discussed on a separate series of articles beginning

at MODULAR HOME CONSTRUCTION.

Characteristics of Panelized Construction

Panelized construction makes use of wall, floor, ceiling or roof "panels" which have been framed off-site and brought to the site by truck. Panels are lifted into place by crane and fastened together on a foundation, and possibly a framed-in floor which have been prepared before the panels arrive.

Some framing panels make use of special materials, such as plywood and foam roof panels for insulated cathedral ceilings

This set of definitions and identifying characteristics of these homes and construction methods is a supplement to our more detailed paper,

MOBILE HOME INSPECTIONS

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Reader Comments, Questions & Answers About The Article Above

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On 2019-05-30 by ruth d. - mobile homes and doublewides are planets apart: a catalog of mobile home defects & difficulties

well mobile homes and doublewides are planets apart from your , reg. stick built, plus if you have wood skirting, the amount of passive air vents, could easly double, and then some,

also with high humidity, and rain falls, and so, many more vents, are being installed, and also another floor vapor barrier over the old one, which is a yeomans job,

major job, with all the wood skirting , still up, and the width of 28 ft. x 6i8 ft., length, and anchor straps, and the piers, in the way,

with work lights, and knee and elbow pads, a head cap covering your ears and head from spiders, ect., sharp rocks under the old plastic floor liner, and only enough crawlspace for , in some spots, less than, 15 inches between you and the steel I beam frame,

I know ive done it, now I have to go in and redo the vapor retardant floor barrier, thoughout,

much better than the clowns that installed it , when we bought it,

ive by hand , pick axe and shovel, dug a outside trench, 2 ft. wide by 1.5 indeep approx., in hard rock clay, and swung the ditch around to the side of yard where the ground starts to slope, away, for rain runoff, plus installed gutters with long extenders, and pitch, with there own trenches, to keep all roof water away from foundation, under crawlspace,

but the wood skirting , needs even more vents, and a better liner for dirt floor,

the moisture is from sweating, due to humid summers in MO.,

you cannot use a dehumidifier in a situation like this even if you could afford one for 1904 sq. ft. or so space, because, they are too damn tall to get them inside in the center of the crawl, plus what about draining it out?,

no one, I mean no one is going to crawl in every other day of there life, to drain it out, they just aint practical,

cost a ton of money,

so are exhaust fan vents, if , you don't do everything else first right anyway, and then youd have to know where to place the one , or two, exhaust fan vents, for proper, locations, and you only have 2 outlet plugs under there plus running your elec. bills up , more every 2-3 seasons of the year, now if we finally get enough venting done, and still moisture, then the vapor barrier needs installed, 6 inch up all walls, and 1 ft. overlays ,

we aint gonna do no stapling, or sealtapes, just overlays,

best as we can, this is a major job as it is, and ,also you want pest control acsess to interior as well as exterior, bottom of wood skirting, every year,

the clay soil, exposure there would be minimal,

beyond all this if we still have too much moisture under there, then we might have to close some of the vents, with , pieces of thick pond liner stapled over certain vents., these are 8x 16 inch alum. soffit vents, once cut out from wood skirting , leaving 1 inch on all sides for screws are really, 6x 14,

so you see , the vents, and cutouts, are , less than the required 1 ft. per 150 ft. of crawlspace,

im discusted by the lack of real info.,

plus , some parts , the height of crawl is higher than , the rest,

so no one wants to help calculate, the height, into it, for venting purposes, we do know that wood skirting , requires even more venting than traditional skirting, if some one could tell us , how to factor in the height, into the math for crawlspace feet, I could get the measuring tape, from points inside, and outside, section by section where height changes, and figure out, each section, by legnth ect., and finally calculate it , real close,

, now those are the 3 things it could be, if after all this, and still too much moisture, well,

that means well need expensive steel siding skirting , cause we aint buying cheap love skirting, like cement board, that it came with, or vinyl love,

I believe we can fix this , and thanks for all the info., but really your not talking to mobile home owners, for crawls,

and there are no standards that are followed in America, for these mobile home gypsy dealers, installers,

on pest control we do it yearly, and sometimes twice yearly, we also installed a pond liner around entire perimeter of wood skirting sides, to keep rainwater there from , rotting the skirting, that's where I do thepest control, lifting the pondliner up, and spraying against termites ect.,

the steel j channel is 1 inch high, that's it, all skirting is way too close to the dirt ground, no standards, no knowledge, no caring , we all do the best we can by gods grace and info., is surely lacking., please talk about mobile and doublewides here, ours has the top vapor , belly wrap, thank god, we already got screwed by our dealer, on many things,

from poor land slope, to bad liner crawl install, ,cheapo love cement board skirting, and other things, and the factory screwed us on the roof, 13 years, it had staples , showing and even nails showing, slap job from factory,

then when we had to switch insurance companies, because , out insurer at the time, was reorganizing or something we had to scramble and get another mobile home type ins., and we thought we had real roof replacement on our policy, but didn't, so we had to pay over 8500 dollars, and , you have to get a indapendant contractor, not the companies, to do this, only a qualified little guy with knowledge,

you cannot reroof over, the trusses are too thin for the weight, and , always need a tearoff, why its so high., plus we needed more roof vents, than the love factory gave, we have no , long ridge vent there, most don't,

, and under the vinyl siding on these things, there is no synthetic, water barrier, installed, so its just the vinyl siding, installed correctly or not between you and disaster,

weve had to redo and come out of our pockets on the 2 sides of vinyl siding, where the dealers, gypsies, installed at the marriage lines,

and our installer got shocked by elec current, of 110 amp., where the factory apes, had the wires running on the outside, of the walls,

behind the foam boards, where you cannot see, behind, so he was nailing into the studs there were he was supposed to install the vinyl, and hit a live line, on both side of home, thank god it was only 110 not 220,

everyone knows elec lines go inside home,

, ok?, this is just some of the stuff goes on with mobile homes, doublewides, ect.,

, you work all your life and buy a home you think , and lookout, the headaches are just beginning.,

most mobile homes doublewides do not have tyvek, or nothing, behind vinyl,

period, no standards at the factory,

whatever they want to do and get away with, the factory was in boaz. Alabama, and 5 years after we bought ours,

new, the factory closed, I wonder why,

champion homes bought the homes from them, that remained, I will give the name here cause I don't care, homes of legend, mobile homes in boaz Alabama,

, awful, construction sloppy at the factory, use the cheapest, products they can get and the workers, probably minumun wage, and mad, so no care how they install things, plus no oversight , from supervisors, like the elec., name of the jerk dealer, was jim l. Williamson,

again im using names cause I don't care, hes a fraud,

so was homes of legend, yeah, legend of love, anyway, were doin everything we can and shouldn't have to, but that is the way it is , no standards, and I mean the newer ones,

there never was any standards on the older ones , and the new standards mean nothing in the realworld.,

America the ripoff, no matter what you buy.

thanks for letting me vent, no pun intended.

On 2017-10-16 by Joe Sark

Question. 1978 doublewide is the roof frame 2X2 construction. I want to install peak shingle roof.

On 2016-10-28 by (mod) - Define Mobile / Manufactured Home: class A B C D etc.

Anon: I have not seen a Class 6 designation for mobile homes. Using WallaWalla Washington's Chapter 20.180 Mobile / Manufactured Home code as an example you'll see definitions similar to those offered in this article.

“Manufactured home, Class A”

means a new multi-wide manufactured home certified as meeting or exceeding the Construction and Safety Standards promulgated by the U.S. Department of Housing and Urban Development and the “acceptable similarity” appearance standards in accordance with Section 20.180.050.

“Manufactured home, Class B”

means a new manufactured home certified as meeting or exceeding the Construction and Safety Standards promulgated by the U.S. Department of Housing and Urban Development but does not satisfy the “acceptable similarity” appearance standards in accordance with Section 20.180.050.

“Manufactured home, Class C”

means a used manufactured home certified as meeting the Construction and Safety Standards promulgated by the U.S. Department of Housing and Urban Development which upon inspection is found to be in good condition and safe and fit for human occupancy.

“Manufactured home, Class D”

means used manufactured homes whether or not certified as meeting the U.S. Department of Housing and Urban Development Construction and Safety Standards or prior codes, found on inspection to be in poor condition and unsafe and/or unfit for residential occupancy. Class D manufactured homes shall not be placed within the City of Walla Walla.

“Manufactured home park”

means a residential use in which more than one manufactured home is located on a parcel of land under single ownership.

“Manufactured home subdivision”

means a platted subdivision in which lots are dedicated for placement of manufactured homes on individually owned lots.

“Mobile home”

means any vehicle or similar portable structure built prior to the enactment of the National Manufactured Home Construction and Safety Standards Act of 1974, designed for mounting on wheels and intended for use as a residence, except parked and unoccupied recreational vehicles, which meets the standards of the Washington Department of Labor and Industries.

“Modular home”

means a dwelling unit constructed in accordance with the standards set forth in the International Residential Code (IRC) and local codes applicable to site-built homes and composed of components substantially assembled in a manufacturing plant and transported to the building site for final assembly on a permanent foundation.

Among other possibilities, a modular home may consist of two sections transported to the site in a manner similar to a manufactured home, or a series of panels or room sections transported on a truck and erected or joined together on the site.

The Walla Walla Municipal Code is current through Ordinance 2016-03, passed March 9, 2016.

Disclaimer: The City Clerk's Office has the official version of the Walla Walla Municipal Code. Users should contact the City Clerk's Office for ordinances passed subsequent to the ordinance cited above.

City Website: http://www.wallawallawa.gov/ City Telephone: (509) 527-4424

Continuing: the numeral 6 is indeed used in some codes such as Minnesota from which we excerpt:

For broader purposes, the definition of manufactured home in M.S. § 327.31, subdivision 6, is substantially the same but also incorporates the provision that a manufactured home in traveling mode, is eight body feet or more in width or 40 body feet or more in length, or, when erected on site, is 320 or more square feet.

- CHAPTER 4: TAX BASE OVERVIEW AND VALUATION OF PROPERTY, Section 04.07 MANUFACTURED HOMES

In turn, Minnesota is referring to a building definition that we also quote:

Subd. 6. Definition of Manufactured home.

"Manufactured home" means a structure, transportable in one or more sections, which in the traveling mode, is eight body feet or more in width or 40 body feet or more in length, or, when erected on site, is 320 or more square feet,

and which is built on a permanent chassis and designed to be used as a dwelling with or without a permanent foundation when connected to the required utilities, and includes the plumbing, heating, air conditioning, and electrical systems contained therein;

except that the term includes any structure which meets all the requirements and with respect to which the manufacturer voluntarily files a certification required by the secretary and complies with the standards established under this chapter.

- Minnesota statute 327.31 DEFINITIONS.

On 2016-10-26 by Anonymous - What is a Class 6 mobile home ?

What is a Class 6 mobile home


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