What is a mobile home inspection?

A mobile home is a prefabricated structure built in a factory and then transported to a site for installation. Originally referred to as "trailers" or "house trailers" in the early 20th century, their design evolved from recreational vehicles into a more permanent and spacious form of housing. The term "mobile home" was widely used until 1976 when the Housing and Community Development Act officially redesignated them as "manufactured homes." This marked a significant shift in their perception and construction, moving from a temporary, mobile structure to a permanent, regulated form of housing.

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The U.S. Department of Housing and Urban Development (HUD) Code governs the design and construction of all manufactured homes built in the United States since 1976. This comprehensive federal building code dictates everything from the home's structure and thermal protection to its plumbing and electrical systems. Unlike site-built homes, which must adhere to local building codes that vary by city and state, manufactured homes must meet this single, uniform national standard. The HUD Code ensures that all manufactured homes meet a minimum standard for safety, quality, durability, and energy efficiency, providing consumer protection regardless of where the home is built or placed.

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A mobile home inspection, as performed by a home inspector, is a specialized process that adheres to the same principles as a conventional home inspection but with a focus on the unique components of a manufactured home. The inspector will examine the home's interior, including the plumbing, electrical, and HVAC systems. However, a crucial part of the inspection is the undercarriage, where the inspector checks the steel frame, the plastic vapor barrier, and the support system, which typically consists of concrete or block piers and tie-downs that anchor the home to the ground. They also inspect the skirting around the home's perimeter for proper installation and condition, as it protects the undercarriage from pests and weather.

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ROOFING

The roofing materials found on a mobile home are typically chosen for their durability, weight, and ease of installation. One of the most common types is a metal roof, which can be very long-lasting and resistant to fire and wind. While durable, they can be noisy during rain and may be susceptible to dents. Another option is an asphalt shingle roof, which is a popular choice for its affordability and familiar appearance. However, shingles have a shorter lifespan than metal and can be easily damaged by high winds. For flat or low-sloped roofs, a membrane roofing system made of materials like TPO or EPDM is often used. These are lightweight, waterproof, and durable, but they require specialized installation and can be susceptible to punctures from falling debris or foot traffic.

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A home inspector's roof inspection on a mobile home is a visual assessment of the roofing materials and components. The inspector will check for visible defects such as missing or damaged shingles, rusted metal, compromised seams, and signs of wear and tear around vents and flashing. However, a significant limitation of this inspection, which is unique to mobile homes, is the absence of an attic. In a conventional home, the attic provides a crucial vantage point from which an inspector can examine the underside of the roof decking for evidence of leaks, water stains, mold growth, or structural issues. Without this access, the inspector is limited to what they can see from the exterior, making it impossible to confirm whether there is any hidden moisture intrusion or damage that is not yet visible on the outer surface.

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STRUCTURE

Mobile homes are built on a non-removable, heavy-duty steel chassis that serves as the permanent foundation. The entire home is constructed in a factory, where engineers design a structure that is both lightweight for transport and robust enough to withstand the stress of being moved. The frame, walls, roof, and floor are built and assembled in a controlled environment, often in sections, using materials that meet the federal HUD Code. Once transported to the site, the home is placed on a foundation system of concrete or block piers, and it must be properly anchored to the ground using tie-downs. These tie-downs are crucial for reinforcing the home and protecting it from strong winds, especially in areas prone to hurricanes or high-wind events.

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A home inspector's structural inspection on a mobile home focuses on the unique components that provide its support and stability. The inspector will primarily examine the undercarriage, checking the condition of the steel chassis and the floor joists for rust, damage, or signs of water intrusion. They will also assess the support system, ensuring that the concrete or block piers are properly spaced and are not cracked or sinking. The inspector will verify that the home is correctly secured with tie-downs and that the skirting around the perimeter is properly installed and in good condition to protect the undercarriage from weather and pests. This inspection is vital for ensuring the home's long-term integrity and safety.

 

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PLUMBING

Some plumbing details in mobile homes are unique and differ from site-built homes. One of the most significant differences is the use of PEX piping and polybutylene pipes, particularly in older models. While PEX is still widely used in modern construction, polybutylene is known to be a common source of leaks and is a unique concern for mobile homes. Additionally, the drainage system in mobile homes often uses a "wet vent" design, where a single pipe serves as both a drain and a vent for multiple fixtures, which is different from the separate vent stacks found in many conventional homes. Finally, due to the undercarriage design, a mobile home's pipes are more exposed and must be protected from freezing, typically with insulation and heat tape.

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Mobile home water heaters possess a unique nature compared to their conventional counterparts, as they are specifically designed to meet the strict safety and space requirements of a manufactured home. Unlike standard residential units, mobile home water heaters often have a shorter, more compact profile to fit within the limited space of a small utility closet or a dedicated compartment. They come in various power options, including electric, propane, and natural gas, but the venting for gas models is often different, utilizing through-the-floor or direct-vent systems. Furthermore, they are typically equipped with an energy cut-off (ECO) switch to prevent overheating, which is a key safety feature required by the federal HUD code. Due to their specific design, it is crucial to use a water heater that is approved for manufactured housing to ensure proper and safe operation.

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A home inspector's plumbing inspection on a mobile home is similar to a conventional inspection but with a specific focus on the unique plumbing details. The inspector will operate faucets and flush toilets to check for proper function and drainage. They will also inspect all visible plumbing for leaks or signs of past water damage. A key part of the inspection is examining the exposed plumbing in the undercarriage, which is a unique area of a mobile home. The inspector will look for any signs of leaks, rust, or improper repairs and will also check for the presence and condition of insulation and heat tape on the pipes. This is a critical step in a mobile home inspection, as these exposed pipes are particularly vulnerable to damage.

 

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ELECTRICAL

Electrical systems in mobile homes have a few unique details that differ from those in site-built homes. One key difference is the use of an aluminum wire, especially in older mobile homes. While aluminum wiring is not inherently unsafe, it requires specific installation techniques and can be a fire hazard if not properly maintained. Additionally, mobile homes often have a single main electrical panel that can be located on the exterior of the home, different from the more common interior placement in conventional homes. The wiring itself is often run through the walls and ceiling as a complete unit before the home is put together, making it difficult to access and repair.

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In mobile homes, particularly those built several decades ago, it is quite common and age-appropriate to find undersized electrical panels, such as those with a 50-amp service. This is not necessarily a defect, as these panels were more than sufficient for the power needs of the time, given that older mobile homes had fewer appliances and less demanding electrical loads. While a modern home typically requires a 100-amp or 200-amp service, a 50-amp panel may be perfectly adequate for an older mobile home unless the owner has added high-demand appliances. An inspector will note this as an age-appropriate condition rather than a major defect, though they will highlight any potential for overload if the home's electrical needs have changed.

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A home inspector's electrical inspection on a mobile home is a visual and functional examination of the unique electrical systems. The inspector will check the main electrical panel, which is often located on the exterior of the home, to ensure it is in good condition and properly rated. They will also inspect all visible electrical outlets, switches, and fixtures for proper function and signs of damage or improper wiring. Because the wiring is often inaccessible inside the walls, the inspector cannot see the full system, but they will look for signs of overheating or shorts. They will also check for the presence of aluminum wiring and recommend a qualified electrician for further evaluation if they find any concerns.

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HVAC

HVAC systems in mobile homes have unique details that set them apart from conventional systems. One of the most significant differences is the use of a down-flow furnace, which is designed to be more compact and to distribute heated air through ductwork located in the floor. This is in contrast to the up-flow or horizontal-flow furnaces common in site-built homes. The ductwork itself is often a crucial part of the inspection, as it's typically made of thin, flexible material that runs through the crawlspace, making it vulnerable to damage, leaks, and disconnections.

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Mobile home furnaces have distinct variations that set them apart from conventional residential furnaces. These units are built to be more compact and lightweight, fitting into the home's limited closet space. They are typically downflow furnaces, meaning they pull air from the top and distribute it downwards into the floor ductwork. In contrast, most site-built home furnaces are upflow, pushing air up through ducts in the walls. Mobile home furnaces also have a unique venting system, often using a sealed combustion air intake and exhaust pipe that vents directly out the side of the home, different from the vent pipes that run through a chimney or roof on a conventional home. They are designed to operate within the specific airflow requirements of a mobile home's duct system, which is typically smaller and more restrictive than a conventional home's, making a standard furnace an unsuitable and potentially dangerous replacement​​

 

In mobile homes, particularly in dry climates, swamp coolers, also known as evaporative coolers, can be a highly useful and energy-efficient alternative to traditional air conditioning. A swamp cooler works by drawing outside air through water-saturated pads, which cools the air through evaporation. This process also adds moisture to the air, making it more comfortable in arid environments. Swamp coolers are significantly cheaper to operate than central AC units and are a popular choice for mobile homes due to their lower initial cost and simpler installation.

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A home inspector's HVAC inspection on a mobile home is a functional and visual examination that pays close attention to the system's unique design. The inspector will turn on both the heating and cooling systems to ensure they are operating and that air is flowing to the registers. They will examine the down-flow furnace for safety hazards like a cracked heat exchanger and inspect the condenser unit outside. A critical part of this inspection is examining the exposed ductwork in the crawlspace for leaks, tears, or disconnections, as these are common points of failure that can lead to energy loss and poor performance. The inspection is non-invasive and provides a snapshot of the system's condition at the time of the inspection.

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Exterior

The most common siding materials for mobile homes are vinyl siding, aluminum siding, and sometimes T1-11 plywood siding. Vinyl siding is popular for its low cost, easy maintenance, and resistance to rot and pests. Aluminum siding, once the standard for mobile homes, is lightweight and durable but can be prone to denting and is difficult to repair. T1-11 plywood siding offers a more traditional wood look but requires regular painting and maintenance to prevent deterioration from moisture and sun exposure. These materials are chosen for their cost-effectiveness and their ability to withstand the rigors of being transported from the factory to the homesite.

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Mobile home siding has a unique vulnerability due to the home's construction and foundation. The skirting around the base of the home is a crucial component of the exterior, as it protects the undercarriage from weather and pests. Damage to the siding or skirting, often caused by improper maintenance, wind, or impacts, can lead to serious issues. A common problem is moisture intrusion behind the siding, which can lead to concealed mold growth or rot in the wooden framing. A larger culprit for moisture intrusion in the siding is the lack of eaves. This would provide some coverage and channel water out and away from the wall. The addition of patio covers is a common fix for this issue and it's HIGHLY recommended. Additionally, if the skirting is damaged or improperly installed, it can allow rodents and other pests to enter the undercarriage, which can lead to damage to insulation, wiring, and ductwork.

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A home inspector's exterior inspection on a mobile home is a visual examination of all accessible exterior components. The inspector will walk the perimeter of the home, checking the condition of the siding for signs of damage, such as dents, cracks, or missing sections. A critical part of this inspection is examining the skirting around the entire foundation for proper installation and condition. They will look for any gaps, cracks, or signs of pest entry. The inspector will also check for proper drainage and grading around the home's perimeter to ensure that water is being diverted away from the foundation. This inspection is vital for identifying issues that could affect the home's structural integrity and overall health.