Mobile Home Inspection Checklist: What's Different and What to Watch For

Mobile homes — now more commonly called manufactured homes — represent a significant share of the US housing market, particularly in rural areas and the South. They're also among the most underinspected properties buyers purchase, partly because many buyers assume the inspection process is the same as for site-built homes.

It isn't. Manufactured homes have different construction standards, different failure modes, and different inspection priorities than stick-built houses. Some of the most critical components that inspectors focus on for a site-built home require a completely different approach for manufactured housing — and there are several failure modes unique to manufactured homes that standard inspection checklists don't even address.

This guide walks through a complete manufactured home inspection framework: what's different about the inspection process, what to look for in each area of the home, and the red flags that most frequently turn into expensive problems.

The Key Difference: HUD Code vs. Local Building Codes

Site-built homes are constructed to local building codes enforced by the municipality. Manufactured homes built after June 15, 1976 are built to the HUD Code — the Federal Manufactured Home Construction and Safety Standards — which is a national standard administered by HUD rather than local jurisdictions.

This distinction matters for inspection because:

• The inspector must evaluate the home against HUD Code requirements, not local building codes
• Additions and modifications made after the home was sited may or may not meet HUD standards, the state installation code, or local code — and often meet none of them
• Pre-1976 "mobile homes" predate HUD Code entirely and should be approached with particular caution; financing and insurance for them is significantly more difficult

When hiring an inspector for a manufactured home, confirm that they have specific experience with HUD-code manufactured housing. Not all general home inspectors do. Some states require specific licensing for manufactured home inspection.

The HUD Data Plate

Before the inspector even begins their walkthrough, locate the HUD Data Plate. This is a paper document affixed inside the home (typically in a cabinet, near the electrical panel, or in a bedroom closet) that contains the certification label number, the manufacturer's name and date of manufacture, the wind zone and thermal zone the home was designed for, and the roof live load rating.

If the Data Plate is missing, the home loses its HUD certification — which can make it very difficult to insure, finance, or resell. Note this as an immediate red flag.

Also locate the HUD Certification Label (also called the "red tag"), a small aluminum plate affixed to the exterior of each section of the home. Each section gets one label. A double-wide has two. Missing tags are significant.

Exterior Inspection Checklist

Skirting

Skirting is the material that encloses the space between the home's undercarriage and the ground. Unlike the foundation on a site-built home, skirting is not structural — its job is to protect the undercarriage from weather, pests, and moisture.

Look for:

• Gaps or missing sections that allow moisture, wind, and pests to access the undercarriage
• Skirting installed without proper ventilation (should have 1 square foot of ventilation per 150 square feet of underfloor area)
• Signs of animal entry — rodents and snakes commonly nest in the undercarriage
• Moisture staining or mold growth on the inside face of the skirting

The Undercarriage

Accessing the undercarriage is one of the most important parts of a manufactured home inspection and one that many general inspectors skip because it requires crawling under the home. Insist on a full undercarriage inspection.

Look for:

• Steel chassis condition: The home sits on a steel chassis that should be checked for rust. Surface rust is common; severe corrosion at the outriggers (the cross-members that support the floor) is a serious structural problem.
• Pier and blocking condition: The home must be properly supported on piers at specified intervals. Sunken, leaning, or missing piers cause floor bounce, racking of the walls, and door and window alignment problems. This is one of the most common and most expensive findings in manufactured home inspections.
• Tie-down straps: In wind zones II and III (much of the South and coastal areas), homes require over-the-roof or frame tie-downs to resist uplift. Check that tie-downs are present, tensioned, and undamaged.
• Vapor barrier: The ground beneath the home should be covered with a plastic vapor barrier to prevent moisture from migrating up into the floor system. Gaps, tears, or pooled water beneath the barrier are red flags.
• Ductwork and plumbing: HVAC ducts and water supply lines in the undercarriage are exposed to weather and pests. Check for disconnected duct sections (common), rodent damage to supply lines, and insulation condition on both.

Roof

Manufactured home roofing systems differ from site-built homes in a few key ways. Most have low-slope roofs (low pitch), which collect standing water differently than steeply pitched roofs. Older single-wides often use metal roofing with exposed fasteners.

Look for:

• Metal roofing: rust at exposed screw or nail heads is the primary failure mode. Lifting panels at the eaves.
• Shingle roofing: same criteria as site-built (granule loss, curling, missing shingles) but pay particular attention to the edges where the roof overhangs are minimal.
• Roof-over systems: many older manufactured homes have had a pitched "roof-over" framed and installed over the original low-slope roof. This can be a good upgrade, but it also adds significant weight. Inspect for signs of inadequate support or moisture trapped between the two roof layers.

Exterior Doors and Windows

Manufactured home windows and exterior doors are typically lighter-duty than site-built equivalents. They are a common source of air and water infiltration.

• Check that all windows operate, lock, and seal properly
• Look for cracked, broken, or fogged glazing (failed seals on double-pane windows)
• Check door thresholds for gaps and weatherstripping condition
• Exterior door frames: look for delamination or rot at the corners where the frame meets the cladding

Interior Inspection Checklist

Floors

Floor condition is one of the most telling indicators of a manufactured home's overall health. The floor system consists of wood framing (typically 2x4 or 2x6 joists) covered by oriented strand board (OSB) or particleboard decking, then finished flooring on top.

The critical problem: particleboard decking — used heavily in manufactured homes through the 1990s — absorbs moisture and deteriorates irreversibly. Once it softens, it cannot be effectively repaired in place; the flooring must be replaced. Moisture reaches the decking most commonly from:

• Plumbing leaks under sinks and toilets
• Roof leaks that work their way down through the ceiling
• Condensation from inadequate undercarriage vapor barrier
• Water intrusion through failed door or window seals

Walk the entire floor systematically, pressing down with your foot every few steps. Soft spots, bounce, or a spongy feel indicates deteriorated decking. Check specifically in front of the refrigerator (ice maker line leaks), under all sinks, and around the toilet base. These are the highest-risk locations.

If any soft spots are found, probe the area further — the affected zone is almost always larger than it first appears. Full floor replacement in a manufactured home costs $3,000 to $10,000 depending on the home's size.

Walls and Ceilings

Manufactured home wall panels are typically thin (often 3/8" or 7/16") vinyl-covered gypsum board or thin paneling. They show water damage more readily than conventional drywall.

Look for:

• Buckling, swelling, or separation of wall panels at seams (moisture behind the wall)
• Ceiling sag or staining (roof leak or condensation in the attic)
• Cracks at the marriage wall — the seam where the two halves of a double-wide connect. Some cracking is normal due to settling, but significant gaps or persistent cracks can indicate that the home was improperly set or that the marriage wall connection has degraded.

In double-wides, inspect the marriage wall connection in the attic. The two roof sections must be properly sealed and joined. A failed marriage wall seal is a primary cause of water intrusion in double-wides.

Plumbing

Manufactured homes often use different plumbing materials and configurations than site-built homes.

• Supply lines: Older homes may use polybutylene (grey flexible plastic), which is prone to sudden failure. Newer homes use PEX, which is generally reliable. Check under sinks for the supply line material.
• Water heater: Often located in a small closet. Check the same criteria as any home: age (from the serial number), rust at the base, proper TPR valve installation and extension.
• Drain lines: ABS plastic is common and generally reliable, but check all accessible drain connections under sinks and in the undercarriage for disconnections.

Electrical

The electrical system in a manufactured home must meet HUD Code electrical standards at the time of manufacture, which are similar but not identical to the National Electrical Code (NEC).

• Main panel: Check breaker condition and amperage. Verify no double-tapped breakers (two wires on one breaker terminal) in the main panel.
• Outlets: Test operation; check for GFCI protection in kitchens, bathrooms, and exterior outlets.
• Service entrance: Examine the connection from the utility pedestal to the home. This is a common failure point, particularly in older single-wides with service connections that have been spliced or extended.

HVAC

Most manufactured homes use either a central forced-air gas furnace with a duct system running through the undercarriage, or a heat pump/package unit. Check:

• Furnace age and condition (same criteria as site-built)
• Undercarriage duct condition — disconnected or deteriorated duct sections in the undercarriage are extremely common and result in significant heat loss
• Propane systems: if the home uses propane, check tank condition and look for any gas odor near appliances or the furnace compartment

Common Manufactured Home Red Flags

Soft spots in the floor: The most common and most expensive finding. Don't walk away from a home just because of one soft spot under a sink, but do get a contractor's estimate before closing.

Missing or unreadable HUD Data Plate or Certification Labels: Affects financing, insurance, and resale.

Pre-1976 construction: These homes predate HUD Code and are often considered personal property rather than real property. Financing options are limited and conventional mortgages typically don't apply.

Unpermitted additions: Room additions, porches, and carports added after the home was sited frequently don't meet HUD Code or local requirements. These can affect insurance and create liability for the new owner.

Marriage wall problems (double-wides): A poorly set or settled double-wide can have a failed marriage wall connection that's expensive to repair properly.

Soil movement under piers: If the soil beneath the home has shifted, sunken piers must be repositioned and re-leveled. Full re-leveling of a double-wide costs $1,500 to $5,000.

Roof-over without engineering: A pitched roof framed over the original roof adds substantial weight. If it was done without engineering the new load into the original wall framing, it can cause structural problems over time.

Getting a Quote Before You Close

Because manufactured home inspection findings — particularly floor and pier issues — can escalate in scope once work begins, it's worth getting contractor estimates for any significant finding before your inspection contingency expires. A soft floor area that looks like a two-room problem can turn into a whole-home floor replacement once the subfloor is exposed.

Negotiate repairs as credits rather than asking the seller to repair. You want to control the contractor and the quality of work, particularly for structural and moisture-related repairs in a manufactured home.

Our Home Inspection Checklist includes a manufactured home section that walks you through undercarriage, pier, and HUD compliance checks alongside the standard room-by-room framework — everything you need to approach inspection day with confidence. Download it for $14.