Tiny House Legal Structures: RV vs. ADU vs. Park Model
If you're researching tiny house legal structures, you've likely encountered three overlapping categories: RV, ADU (Accessory Dwelling Unit), and park model. The confusion is understandable—these terms describe different legal classifications, not different sizes or styles of homes. Choosing the wrong category for your situation can lead to zoning problems, financing complications, or being unable to live in your tiny home full-time. This article breaks down the legal and practical differences between these three structures, helping you match your lifestyle goals with the right classification.
The Core Distinction: Legal Classification, Not Size
"Tiny home" is not a legal category recognized by building codes or zoning ordinances—it is an idea, not a formal classification. In building codes, there is no official Tiny Home classification. The term has come to describe any compact, intentionally small living space, typically between 100 and 400 square feet (some use 500 square feet as the cutoff). The legal reality depends entirely on how the structure is classified under building codes and local regulations. The three main legal categories are: RV (Recreational Vehicle) built to RV codes (CSA Z240-RV in Canada or ANSI 119.2 in the USA), designed for temporary or seasonal use and considered personal property; Park Model RV, a larger RV subtype built to ANSI A119.5 standards (CSA Z241 in Canada), also classified as personal property; and ADU (Accessory Dwelling Unit) built to residential building codes, placed on a foundation, and considered real property. [1][2][3][5]
RV Classification: Mobility and Flexibility
What Makes a Structure an RV
An RV is built to recreational vehicle codes—in the US, typically ANSI 119.2, or in Canada CSA Z240-RV standards. These structures are designed for temporary or seasonal occupancy, not permanent year-round living. They come with a Vehicle Identification Number (VIN) and are titled as vehicles, not real estate. [1][3][5]
Tiny houses on wheels (THOWs) often fall into this category if built to RV standards. However, many custom-built THOWs do not meet RV code requirements and exist in a legal gray area. Most tiny homes on wheels are not considered permanent residences under local zoning laws and may be classified as RVs or trailers. Depending on how they're built, they may or may not be certified by organizations like the RVIA, which affects where they can be legally placed and how they can be insured or financed. [2][6]
Where You Can Place an RV
RVs are generally allowed in RV parks and campgrounds. However, many jurisdictions restrict how long you can stay in one location. If your municipality reads "RV," you're boarding seasonality. Some areas may allow tiny homes on wheels to be parked on private property, while others restrict them to RV parks or designated tiny home communities. [1][2][4]
Financing and Insurance
Tiny RVs and park models get RV insurance and loans; modular dwellings are financed via mortgages and insured like real homes. Because RVs are classified as personal property, they generally depreciate in value over time, similar to vehicles. [1][3][4]
Practical Considerations for Towing
Most tiny house RVs must remain under 8.5 feet in width to be road legal without special permits. Park models are wider than 8'6" and need permits for transport. [1]
Park Model RV: Larger but Still Seasonal
What Defines a Park Model
A park model is built to ANSI A119.5 standards (CSA Z241 in Canada), the same RV code used for recreational vehicles. It receives an ANSI certification label affixed directly to the structure—a credential recognizable to insurance underwriters, campground operators, and lenders. Park models are wider (11–12 feet) and larger than standard RVs, typically under 580 square feet. Every park model manufactured in the United States must comply with ANSI A119.5, the national safety and engineering standard that governs structural integrity, electrical systems, plumbing, and fire safety for recreational park trailers. [1][3][4][5]
Park models are produced by major manufacturers including Cavco, Skyline, Kropf, and Athens Park Homes. They arrive at their destination as a finished product—paint, cabinets, appliances, flooring, and all—and are typically skirted and connected to 50-amp electrical service, city water, and sewer within days of delivery. [3]
Critical Limitation: Seasonal Use Only
Despite their residential appearance, park models are legally restricted to seasonal or recreational use. They are not approved for permanent year-round occupancy under RV codes. Most municipalities explicitly prohibit using an RV—including a park model—as a full-time primary residence on private land outside of an approved RV park. Park models offer more comfort than RVs but remain restricted to seasonal habitation. They carry VINs, need RV financing, and aren't valid as a permanent dwelling. [1][3][4][5]
Transport and Relocation
Moving a park model requires professional transport with a semi-truck and oversize load permits. The cost of hiring professional movers can range from $1,500 to $5,000+ due to their wide 11–12 foot frames. [3]
Financing and Depreciation
Like standard RVs, park models can be financed with RV loans and insured with RV policies. Additionally, they depreciate over time like a vehicle and often feature lighter, factory-grade materials rather than high-end residential finishes. [1][3]
ADU Classification: Permanent Real Estate
What Makes a Structure an ADU
An Accessory Dwelling Unit is a secondary residential structure built on the same lot as a primary home. ADUs are constructed to local residential building codes (typically the International Residential Code or IRC) and placed on a permanent foundation. They are classified as real property, meaning they become part of the land's value and title. [2][5][6]
Full-Time Living Approval
Unlike RVs and park models, ADUs are legally approved for year-round occupancy. They must meet all residential building code requirements, including proper foundation, utilities, and safety standards. Foundation-based tiny homes can serve as primary residences if zoning laws allow, and may range up to around 600 square feet depending on local definitions. [2][5]
Property Value and Investment
Because ADUs are real property, they appreciate in value along with the land and primary home. Financing is available through traditional mortgages, and insurance is treated as real estate coverage. [1][4][6]
Local Regulations Vary
ADU regulations differ significantly by location. Cities and counties retain final authority over zoning, setbacks, architectural standards, fire access requirements, environmental overlays, and allowable use. Always verify with your local zoning department before planning an ADU project. [3][5]
Comparison Table: Key Differences at a Glance
| Feature | Tiny House RV | Park Model RV | ADU (Modular/Foundation) | |———|————–|—————|————————–| | Building Code | RV standards (CSA Z240-RV or ANSI 119.2) | RV standards (ANSI A119.5 or CSA Z241) | Residential building codes (IRC) | | Permanent Occupancy | Not approved for year-round | Seasonal use only | Yes, fully legal | | Foundation | Wheels | Wheels | Permanent foundation | | Property Classification | Personal property (vehicle) | Personal property (vehicle) | Real property (real estate) | | Financing Type | RV loan | RV loan | Mortgage | | Transport | Towable with pickup truck | Requires professional semi-truck and oversize permits | Not transportable once placed | | Typical Width | 8.5 feet | 11–12 feet | Varies by design | | Ideal Use | Travel, vacation, flexible living | Camp retreats, seasonal rentals | Full-time living, long-term rental |
*Sources:* [1][3][4][5]
How to Choose the Right Structure for Your Situation
Step 1: Define Your Use
Ask yourself: Will this be full-time housing, part-time vacation space, a rental property, or something else? The answer determines which legal categories are even available to you. [1][2]
Step 2: Check Local Regulations
Contact your local planning or zoning office to understand specific requirements and restrictions in your area. Determine whether your tiny home will be classified as a permanent dwelling, an RV, or an ADU, as this will affect where it can be legally placed. Consulting with architects or builders experienced in tiny home construction can help navigate building codes and design specifications. Your town's bylaws will define whether your tiny space can stay year-round or needs reclassification as an ADU or single-family home. [1][3]
Step 3: Match the Structure to the Site
The home should fit the legal path available for your property, not just your wish list. If your area does not allow ADUs, a park model might be your only option—but only if you accept seasonal use limitations. [1][4]
Step 4: Budget for the Full Project
The purchase price is only part of the cost. Factor in delivery, site preparation, utility hookups, permits, insurance, and ongoing costs. For a park model, the cost of hiring professional movers can range from $1,500 to $5,000+. For an ADU, construction costs vary widely by location and design. [3]
Common Pitfalls to Avoid
Assuming "tiny home" is a legal category. It is not. Your structure will be classified as an RV, park model, or ADU based on its construction and foundation, not its size. In building codes, there's no official Tiny Home classification. [1]
Buying a park model for full-time living. Park models are legally restricted to seasonal use. Living in one year-round may violate local codes. Park models are meant for park or campground use. [1][3][4][5]
Building a custom THOW without checking RV certification. Many custom tiny houses on wheels do not meet RV code standards. This can make them difficult to park legally, finance, or insure. Most tiny homes on wheels are not considered permanent residences under local zoning laws and may be classified as RVs or trailers. [2]
Assuming local rules are the same everywhere. Regulations vary by county, city, and even neighborhood. At the national level, there are no uniform standards for tiny homes. Instead, they fall under various categories such as recreational vehicles, mobile homes, or accessory dwelling units, each with its own set of rules. [2][3]
Final Recommendations
For full-time, permanent living in a location you own, an ADU built to residential codes on a foundation is the most legally sound option. It provides equity, financing options, and year-round approval. Foundation-based tiny homes can serve as primary residences if zoning laws allow. [2][5]
For seasonal or recreational use where you can accept limited occupancy, a park model offers more space and a residential feel while remaining classified as an RV for financing purposes. Park models are welcomed at virtually every RV resort, campground, and tiny home community in the country. [3]
For flexibility and mobility—traveling, relocating frequently, or testing the tiny house lifestyle—a certified tiny house RV (built to RV codes) gives you the freedom to move while maintaining legal compliance. Tiny Home RVs can be customized to your needs, are built for cold weather climates, and can be comfortably used in any Canadian season. [1]
In all cases, verify current regulations with your local zoning department before making any purchase or beginning construction. Laws change, and local interpretations vary. When you talk to insurance brokers, financers, and municipalities, words matter—calling yours a "Modular ADU" means a different set of rules and approvals than calling it a "Tiny Home RV." [1]
Sources
[1] https://www.teacuptinyhomes.com/blog/tiny-home-rv-vs-park-model-vs-modular-dwelling-what-s-the-difference
[2] https://truformtiny.com/blog-park-model-tiny-home-rvs
[3] https://hearthbuilthomes.com/tiny-house-vs-park-model
[4] https://www.westcoast-homes.com/yourguidetotinyhomesandparkmodels
[5] https://www.nwtinyhomes.com/regulatory-placement-disclaimer
[6] https://www.zentinyhomes.com/post/adu-vs-tiny-house-one-is-a-real-estate-investment-the-other-is-a-lifestyle-choice
