Mobile home water heater (C) Daniel FriedmanHow to Inspect & Troubleshoot Mobile Homes,
Double wides, Caravans, Manufactured Homes, & Trailers

  • MOBILE HOMES, DOUBLEWIDES, TRAILERS - home - CONTENTS: Mobile home, trailer, doublewide, manufactured home inspection & troubleshooting guide. Definition and description of mobile homes, double wides, trailers, caravans and campers.
  • POST a QUESTION or READ FAQs about inspection of the condition of manufactured homes, mobile homes, mobile home, caravan, static caravan or trailer or doublewide problem diagnosis procedures, & their care, repair, & maintenance

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How to Inspect Double-Wides, Mobile Homes, Trailers or Manufactured Housing for Defects:

Included in this article series are detailed inspection procedures, defect lists, codes. We explain where to look for costly or dangerous problems on manufactured homes or mobile homes, trailers, or double-wides.

We include lists of defects found on manufactured or mobile homes, trailers, double-wides, caravans, static caravans. You also will find a guide to safety codes for manufactured / mobile homes: the federal and other building codes regulate manufactured homes, mobile homes & doublewide homes. Wind & tie-down regulations for mobile homes & double-wides are included.

We address all of the major parts and systems of manufactured or mobile home structures and suggest field inspection procedures as well as common hidden problem and common repair procedures. This article series includes copies of manufactured home & mobile home codes & standards as free down-loadable PDFs.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Inspection & Repair of Manufactured Homes, Doublewides, Caravans & Mobile Homes

Photograph of  this much-modified trailer - this is not a modern mobile home.

Article Contents

Ver.16 , updated through 2017 - Steve Vermilye, New Paltz NY and Daniel Friedman, Poughkeepsie NY, Hudson Valley ASHI Chapter Seminar, Newburgh NY, January 4, 2000, NY Metro ASHI Fall 99 Seminar, Holiday Inn Crowne Plaza, White Plains NY, October 2, 1999.

With deep sorrow we report that our friend and associate, Steven T. Vermilye of New Paltz NY (photo at the top of this page) passed away on 19 June 2001, so of course you will have difficulty contacting him by normal means.

Steve was a leader in the home inspection profession, recognized nationally as well as among New York State professional home inspectors for his competence, kindness, honesty, humility, humor, and for his unequivocal commitment to the welfare of his clients.

Steve led our interest in mobile home inspections by offering us an opportunity to join with him to work pro-bono in behalf of agricultural workers in the Hudson Valley -- a service which we continue in his memory.

Definitions of Mobile Home, Trailer, Doublewide, Modular Home, Factory-Built Home, Panelized-Construction-Built Home?

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 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.

Our photo (left) shows a trailer that was finally abandoned as a living space. 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. The closest thing to a "trailer" in current products on the market are motor homes and campers.

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 2014), "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.

Definitions: If you are not sure if your home is a mobile home, trailer, double-wide, caravan, or a modular or panelized-built or factory built home, please see DEFINITIONS of Mobile Home, Doublewide, Modular, Panelized Construction

We found so many unsafe and un-healthy conditions in the trailers and mobile homes occupied by migrant farm workers that there was almost no safe habitable housing at the facility.

Mobile home on pad (C) Daniel Friedman

The facility owner, responding to suggestions from our report and from the N.Y. Office of the Attorney General and an attorney representing farm workers made extensive improvements in farm worker housing as a result of Steve's initiative.

Many of the photographs used to illustrate defects and needed repairs at these mobile homes, trailers, and double-wides came from Steve or from our own photos when we worked together.

We all miss Steve Vermilye and his passing remains a great loss. If the information in this report assists anyone in assuring that their home is more safe and secure than it would have been otherwise, that benefit is thanks to Steven Vermilye -- this information is one of his many gifts to the people for whom he cared deeply -- Daniel Friedman.

Consumer Reports (2/98) points out common weak spots surveyed and recommends that buyers hire a home inspector. But many inspectors are not familiar with the special problems found in mobile homes.

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

These terms are defined at TRAILER VS MOBILE HOME VS MODULAR VS PANELIZED CONSTRUCTION an explanation of terms and how to identify these structures.

PRIORITIES OF INSPECTION & Reporting of Manufactured Home / Mobile Home Defects

Modern mobile home or doublewide in good condition (C) Daniel Friedman

MOBILE HOME FIRE SAFETY - Fire Safety Defects in Manufactured Homes

The double-wide home shown at left, as seen from a distance, appears to be in good condition, but only on close and thorough inspection can we become confident about the condition of and potential safety hazards at any home.

Mobile Home & Trailer STRUCTURAL & SAFETY DEFECTS in Manufactured Homes

Mobile home piers and shims (C) Daniel Friedman

Trailer or mobile home foundations and tie-downs are discussed in detail at MOBILE HOME STABILIZING SYSTEMS

Other Common Mobile Home & Trailer Defects

Leaky mobile home windows (C) Daniel Friedman

Manufactured Home Labels & Mobile Home Labels & Manufactured Housing Labels & Certifications


Mobile Home Moisture & Leak Troubles

Question: How can I track down what's causing high moisture in a doublewide manufactured home?

I have a double wide manufactured home that I'm renovated. It has vinyl siding and perforated soffits common on manufactured homes. We've noticed moisture high in the walls all around the home and can't identify the cause. Any ideas? Thank you, - T.B. - Colorado


A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with too much moisture in a home. That said, gee, with absolutely no information whatsoever about the home you mention, I'd be just arm-waving to offer a specific diagnosis.

But I can suggest some directions of investigation for tracking down a moisture problem:

Generally the approach is to find the water sources and water or moisture traps. That is, high indoor moisture, enough to put condensation on walls, might be tracked down to one or both of:

  1. Leaks or moisture sources that are wetting the building interior or its ceiling, wall or floor cavities or space below. These could be leaks from outside or moisture generation (cooking, showers, plants, even plumbing leaks) inside.
  2. Traps that keep moisture in the building because it is not adequately vented. Indeed from your note I infer that there is a gabled (peaked/sloped) roof over the home, but we can't be sure that it has working venting or just some perforated soffit panels placed over solid plywood soffits. Or you may have soffit intake but no ridge outlet venting.
  3. Check the crawl space for signs of water entry right in the crawl itself; the skirt around the mobile home can keep the area from drying out. See MOBILE HOME CRAWL SPACES for more details.

If I'm right that you're in Colorado, you're not in such a high humidity area as the Southeastern U.S. That in turn makes me wonder if there is not either water below the home or leaks in or into it from roof, windows or doors (notorious leakers on older manufactured homes).

If the moisture is uniform around all of the interior of the home I suspect it could be coming from a source that would equally wet the whole structure - below the entire structure up through floors, or leaks across a wide area of roof. Observing moisture high on walls may just indicate where the cool walls are in contact with warmer, high-moisture-content air inside the home. (Warm moist air rises).

If your renovation permits, you might need to make some test cuts to be sure you know where water is and is not, and to be sure you're not renovating by putting a new skin over a rotting or inset infested structure.

Sorry I can't be smarter but that's about as much arm-waving as I can dare with no more information. If you'd like to send some photos or further description of what's there and what you're seeing, that may permit some further suggestions.

At WATER ENTRY in BUILDINGS we collect a series of building moisture or water entry diagnosis & cure articles that might be helpful.

Follow-Up: wet walls traced to frost or ice in the home eaves and attic

Photograph of frost in an attic - evidence of a source of attic mold and moisture damage

Thanks for the reply. I managed to find a manufactured home installer who immediately knew what I was talking about.  It turns out all this is a universal problem with manufactured homes (and some stick built homes) in cold, high wind areas. 

The soffits are vented continuously.  Snow actually drifts inside the soffit then, when the weather warms, melts and some water runs down the walls.  As this can happen many days after the initial precipitation it’s often mistaken for a condensation issue.

The installer didn't have any suggestions for a solution.  In fact, he said if I came up with anything to let him know.  Any ideas?


We have seen several points of frost or even ice accumulation at house eaves and even deeper into the attic in uninsulated HVAC ductwork.

Clues that point to the attic ice or frost accumulation as the source of indoor leaks and moisture

I think a diagnostic clue that can help track down apparent building leaks or moisture on walls that originates in the attic may be the observation of leaks in a warming weather trend after a long cold spell. 

Also the moisture shows up only on the exterior walls, not on building interior walls. It doesn't have to be snow blowing into the soffits - which is unusual; anything that allows moisture condense, collect, and freeze in the attic or in attic HVAC ducts can produce such leaks when things thaw out.

The cause your installer cited, snow drifts in the soffits, is possible but more common are some of these other problems that can produce the same symptoms:

How do we fix these problems of ice and frost formation in the attic ... it depends. First let's accurately diagnose the cause by a careful inspection in the attic. Wind-wash will be obvious - insulation will have been disturbed. Ice dam leaks leave characteristic stains that we illustrate in that article.

Details about these attic frost, ice, or moisture problems that show up as "leaks or moisture on building walls" and how they are fixed are in the articles cited above.

At INSPECT ATTICS for MOISTURE or MOLD we discuss inspecting (and correcting) building attics for evidence of condensation, moisture, or even ice.


Continue reading at MOBILE HOME CODES & STANDARDS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see this article series

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