The Big Deal About Legalizing Tiny Houses

By Thom Stanton  |  Tiny House Advocate, Designer, and Builder
Copyright 2017 – All Rights Reserved

A huge downer in most regards, the housing market crash of 2007 and ensuing Great Recession of 2008 may be credited for at least one great outcome: Tiny Houses!

Solid Foundation

Small in stature and a fraction of the cost of traditional homes, today’s tiny houses are built like real homes. But built “like a real home” or constructed to “most of the codes” isn’t the same as building a permissible dwelling to established building codes, sloggin’ through an arduous inspection process, and receiving a bonafide Certificate of Occupancy for a tiny house on a permanent foundation (THOF). 

And for those building a tiny house on wheels (THOW), there are even bigger rubs on the wheeled wells of our tiny hearts and souls. Negotiating the nuances of building codes imperils the Tiny House Movement as modern day waggoners become mired down in conflicting codes, are swamped by legal implications, and stumped by choices on an endlessly forking road. 

Scope and Intent

This article is akin to a journey during which we work to:

• Define relationships between code keeper lingo and colloquial “tiny house” terms;
• Explore associated and applicable building codes and regulations; and 
• Objectively explain how you can safeguard your tiny house habitation.

Throughout, we continually work to illustrate the advantages of building by prescriptive construction standards that are upheld by established authorities and enforcement officials. 

And while this course of action includes many a frustrating twist-n-turn, along with an occasional impedance, our trip together maintains a positive outlook with a wonderful objective in sight: 

Legally permissible tiny home habitation! 

2 Big Keys for Legal Tinies

This article covers both THOFs, for which a building department may hold sway over construction, and THOWs, which are viewed more as RVs and often restricted for use as permanent dwellings. 

For both THOF and THOW alike, we hold that two keys unlock our tiny kingdom: 

Legitimization – In short: Adherence to construction codes.
Refers to building to prescribed construction codes and specifications to gain a certificate of compliance by a credentialed inspection and certification body authorized through an official government entity (e.g. local municipal Building Department) or recognized as defined in consensus standards developed by a group of recognized industry professionals (e.g. ANSI Canvass Method).

Legalization – In short: Stated allowance of Tiny Houses in zoning ordinances.
Leans on land use specified for permissible habitation of a permanent structure (e.g. site-built home), typically granted in the form of a Certificate of Occupancy (CO), or acceptance of a recognized type of movable structure (e.g. Manufactured Home or Recreational Vehicle) as allowed through an approved zoning ordinance. 

NOTE: Areas of “Unrestricted Land” may require conforming to zoning ordinances as the term “unrestricted” varies from one area to another. It is always best to check with local authorities before you build a permanent structure or locate a moveable structure onto a site for use as a semi-permanent residence (sited on blocks with tongue and/or axles removed) or temporary dwelling (e.g. structure classified for recreational use). 

And thus we’ve laid a solid foundation for this crash course of construction codes. It is our hope to help you build your knowledge so you can make an educated choice of direction for your DIY tiny house project or professional interests you have in the Tiny House Movement. 

Key Takeaways:

1. Authorities base enforcement upon application of laws, rulings, and codes.
2. Adherence to construction codes may be required for official approval of use.
3. Zoning ordinances restrict land use, and may be written to allow Tiny Houses.
4. Tiny House on Foundations (THOF) are built on a foundation as a permanent dwelling
5. Tiny House on Wheels (THOW, also Movable Tiny House) have a permanent chassis, and may be considered for use as permanent, semi-permanent, or temporary dwellings.

Building Code Framework

Standards and codes are needed to enhance productivity, facilitate trade, and improve quality of life. Standards may be developed by trade associations, industries, or government agencies.

To you “keep ‘er in the wind and ‘tween them ditches,” you might want a heavy hit of caffeine lest highway hypnosis take hold while digesting the details. It’s easy to lose focus, nod off, or at least go cross-eyed traversing such a dry-n-dusty topic. So hang onto your hats, here come the codes! 

Dwellings Defined

Authorities Having Jurisdiction (AHJ) hold sway over your ability to live legally in a tiny house. A list of codes and/or philosophies that apply to structures used as dwellings follows.

To give ourselves a framework for tiny houses, let’s start with definitions from the International Code Council’s (ICC) International Residential Code (IRC) — the most recognized code set for residential construction in the U.S. — and its newly adopted appendix for Tiny Houses.

DWELLING UNIT – A single unit providing complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation. 

DWELLING – Any building that contains one or two dwelling units used, intended, or designed to be built, used, rented, leased, let or hired out to be occupied, or that are occupied for living purposes.

MANUFACTURED HOME – Manufactured home means a structure, transportable in one or more sections, that in the traveling mode is 8 body feet or more in width or 40 body feet or more in length, or, where erected on site, is 320 square feet or more, and that is built on a permanent chassis and designed to be used as a dwelling with or without a permanent foundation where connected to the required utilities, and includes the plumbing, heating, air-conditioning and electrical systems contained therein.

TINY HOUSE – A dwelling that is 400 square feet (37 m ) or less in floor area excluding lofts. NOTE: The definition of Tiny House in the IRC Appendix excludes “movable tiny houses,”more commonly referred to Tiny Houses on Wheels (abbreviated as THOW).

Now that we’ve seen the officially related definitions, let’s roll ‘em all into one for this article: 

TINY HOUSE – A building of not less than 70 square feet and not more than 400 square feet (excluding lofts) used, intended, or designed to be occupied for living purposes that provide complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.

Key Takeaways: 

1. Tiny houses typically conform to definitions of a single dwelling unit.
2. The term manufactured home currently excludes tiny houses on wheels.
3. Newly adopted Tiny House codes are an appendix in the IRC, and — if accepted as exceptions to the building code — apply to dwellings on permanent foundations.
4. Construction codes can be applied to THOWs, and may become certification standards.
5. THOWs (also “Moveable Tiny Houses”) are not recognized by an official designation. 

Square Footprints

One woman’s tiny house is another man’s mansion as the term “tiny” fluctuates wildly when it comes to square footage. Here’s why size matters when it comes to tiny houses, and the codes that encircle the space in which tiny housers dwell.

70 sqft – IRC minimum for for a single room dwelling albeit a 7’-0” minimum wall length.

200 sqft – Minimum size for an unpermitted accessory structure in many jurisdictions (though permits and inspections may be required for siting to ensure adherence to lot restrictions including easements and setbacks)

320 sqft – HUD minimum for manufactured homes built as dwelling units with a permanent chassis “to assure the initial and continued transportability of the home.” Also the square footage stated in the IRC for minimum size of a manufactured home.

400 sqft – Maximum size for Tiny House codes in IRC appendix, and maximum size for recreational vehicles in “setup mode” with proposed exemption from HUD Code as “a factory-built vehicular structure, not certified as a manufactured home, designed only for recreational use and not as a primary residence or for permanent occupancy.”

2,520 sqft – Median size of new single-family home sold in 2015.

Key Takeaways: 

1. Size is key in differentiation between manufactured home and recreational vehicle. 
2. The space between 320 sqft and 400 sqft is a broad “grey area” with conflicts in code.
3. Means of manufacture of larger tiny houses could be seen as deliberate circumvention of applicable law where manufactured homes are concerned. 
4. A median sized home is 13 times larger than the average THOW (8’x24’ for 196 sqft).

Code Conflicts and Conformation

The above clearly illustrates that the fine points of construction code are conflictingly confusing. 

There are multiple code sets, all built upon layers of dependent definitions, with untold references between code sets. Many municipalities employ a Code Keeper who helps decipher definitions, understand interrelationships, and provide interpretation of interdependent codes. 

There are also conflicts between codes, with some overlaps that require reading into nuances that may limit an ability to easily understand the most appropriate direction to take when building. The soft boundaries between code sets pit tiny house builders and homeowners against Authorities Having Jurisdiction (AHJ) with questions about non-conformation to the proper code.

The big thing to understand about tiny houses, is that the wee little structures we love often sit outside existing codes, but continually bump the border of existing code sets. And that’s an issue from a code enforcement standpoint, and cause for concern for many burgeoning tiny house construction companies as well as DIY “backyard builders.”

Let’s step a bit further down the path to understanding building codes, and their application to tiny houses, helping make the leap from querulous confusion to more fully informed. 

Tiny House Construction Codes

Empowered with a basic knowledge that A) there are building codes, B) some but not all codes apply to tiny houses, C) and codes vary by application and jurisdiction, let’s look at which building codes are most officially associated with and popularly used for construction of a Tiny House.

Outlaw Code

Basic Definition: Building without a dedicated construction code. 

Many professional tiny house builders have years of experience, and find it freeing to build by their own set of best practices. Many tiny house homeowner/builders use internet searches, friendly advice, and common sense as a base for their buildings, and follow what they believe is the “right way” to construct their home. 

A strong belief in what is “right” is not the same as bonafide absolute assurance. Lending agencies, insurance companies, and code enforcement officials usually require absolute assurance of conformation to construction standards. 

In the case of building officials, such assurance usually comes from in-person first-hand observation via preemptive inspection prior to finished construction, or — worse — “destructive inspection” in which a structure is dismantled for inspection of compliance. 

What some consider a well-built DIY tiny house, officials may deem an “outlaw shack” after habitation. Enforcement of a Stop Work Order, demolition of illegal structures, and impoundment of a vehicle (read: THOW) are all within the legal purview of an Authority Having Jurisdiction.

Scary sky-fall consequences aside, it is known to be more difficult to secure financing and affordable insurance for Tiny Houses lacking a manufacturer’s seal or certification of compliance for adherence to accepted construction codes.

Key Takeaway: Proceed at your own risk.

Construction Guidelines

Basic Definition: Best practices promoted by professional contractors and industry experts. 

The American Tiny House Association (ATHA), several tiny house construction companies, many books, and DIY bloggers offer some great construction guidelines for building a Tiny House on Wheels (THOW). 

Guidelines like these generally follow commonly accepted construction principles that can help simplify the head-spinning amount of details required to build a tiny house. Most of these guidelines offer great advice for DIY builders, along with some solid how-to skills and quick tips to help save time and money during construction. Others offer critical recommendations with insight on specialized techniques intrinsic to the construction of THOWs. 

While these may be deemed great resources, they are not a comprehensive code base and usually lack the breadth of information, detailed instruction, and specifications required to meet national, state, municipal, and/or industry accepted certification protocols.

Key Takeaways: 

1. Guidelines and best practices may directly align with portions of building codes.
2. Guidelines may focus on key aspects of construction, though usually lack the level of detail and specification contained within building code books like the IRC. 
3. Guidelines are not a replacement for official construction codes.
4. Referring to specific codes in Guidelines is an underutilized best practice.

RV Codes

Basic Definition: Construction codes applied to manufactured recreational vehicles. 

Because of conditions of transport, size, and use, existing standards for permanent buildings are not completely applicable to recreational vehicles (RV). That said, much of the material contained in these standards was borrowed from or based upon nationally recognized standards for home construction as well as fire and life safety.  

Two predominant code bases are applied to the manufacture of recreational vehicles (RV):

ANSI 119.2 – Also known as NFPA 1192, the Standard on Recreational Vehicles is the code body applied to motorhomes and travel trailers with widths less than 8’-6” during travel mode. This set of prescriptive codes establishes fire and life safety criteria for recreational vehicles to provide protection from loss of life from fire and explosion. Comprehensive coverage includes general requirements, fuel systems and equipment, and plumbing systems. Fire and life safety provisions address interior finish and textile materials, means of escape, fire detection equipment, and vehicular requirements. Due to the inclusion of motorhomes in this standard, this code is less applicable to THOWs than ANSI 119.5 (see below).

ANSI 119.5 – Prescriptive standards for Park Model Recreational Vehicles (PMRV), also known as Recreational Park Trailers (RPT), that provides comprehensive building codes that includes details and specifications for the construction, inspection, and certification of PMRVs. Due to the similarity of construction standards between this standard and the International Residential Code (IRC), ANSI 119.5 is used by many THOW manufacturers as their building code. As for ANSI 119.2/NFPA 1192 all aspects of PMRV construction are included in this comprehensive code base, including code administration, inspection, and certification protocols. 

Where site-built homes are inspected by local building code officials on an individualized basis during construction, recreational vehicles (including RVs, PMRVs, and certified Tiny House RVs) are considered “factory-built” units. As with manufactured homes, RV manufacturing facilities receive a certification of compliance, granting manufacturers the right to issue certification seals as proof of compliance to industry standard manufacturing codes. Thus, it is the facility that is certified, not an individual unit.

Key Takeaways:

1. RV codes may be applied to construction of a THOW, with ANSI 119.5 for PMRVs being the most predominant code used for compliance in the Tiny House industry.
2. Tiny House builders may construct to any specification, though only a manufacturer certified by a third-party compliance firm (like RVIA and Pacific West Associates) may “seal” a tiny house as an official RV.
3. Due to the parameters of RV codes and their conditions of compliance, only turnkey units (i.e. completely finished) may be sealed by a Tiny House RV manufacturer. 
4. Certification of Tiny House RV manufacturing facilities is expensive, and predominantly applicable to those mass producing Tiny House RV units. 
5. Tiny House builders may “meet or exceed” the same RV codes, and many promote that they build by the same standards, though may not have certified production facilities. Facility certification illustrates the meeting of minimal compliance to applicable code, and is not — in and of itself — a guarantee of quality for individual units.

International Residential Code

Basic Definition: Construction code most commonly applied to site-built construction. 

Currently two inches thick at the spine, the International Residential Code was founded from the combination of three regionally accepted building codes in the US. 

As such, the IRC meets public safety needs through proven construction standards, findings from historic data and scientific tests, as well as prescriptive methods to address regional concerns in varying climate zones, areas with seismic activity, locations that experience high winds, and other regionalized variables. 

Every three years, the ICC meets during its Code Development Cycle to hear proposed code changes, review public comments, and vote on elected changes. The voting members are a dispersed body comprised by certified public safety experts, fire marshals, building officials, and industry experts, with built-in means of public response that ensures an even-handed approach to construction code administration.

As for most code sets, the IRC utilizes codes and standards requirements as references throughout, especially those addressing building, electrical, mechanical, plumbing, fire, and maintenance codes, such as: ADA, ANSI, BOCA, IBC, IEBC, IEC, IECC, IFC, IMC, IPC, NEC, NFPA, SBC, UBC, and others where cited.

Many states and municipalities use the most recently published IRC, some an older edition stands as their code for long periods of time, while other areas borrow the bulk of their Uniform Building Code from the IRC with some adaption for special needs in their jurisdictions.

If you are building a tiny house on foundation, call your local building department for details on which guidelines they follow for plan review, construction permitting, and compliance inspection. 

Key Takeaways:

1. IRC can be applied to a Tiny House on Foundation (THOF).
2. IRC generally excludes construction on chassis (e.g. THOW on trailers).
3. IRC is both definitive and referential, defining aspects of construction as well as citing other code sets where their codes or standards apply. 
4. Acceptance of IRC editions vary (3-year cycle), and are often used as the basis for state administered building codes (e.g. Virginia Uniform Statewide Building Code).

Tiny House Appendix

Basic Definition: Prescriptive codes for structures of 400 sqft or less on a permanent foundation.

Proposed by tiny house expert, Andrew Morrison, and others in a coordinated effort, the Tiny House code is a newly accepted appendix included in the forthcoming release of the 2018 IRC. As an appendix, the Tiny House code may be accepted by the governing body of state or local building departments. 

The scope of the IRC only covers dwellings on a permanent foundation, and generally excludes structures on a chassis. As such, Recreational Vehicles and Manufactured Homes, are designed to separate standards. The term Tiny House on Wheels (THOW) is a colloquial term used by the tiny house industry and is not currently not recognized by IRC for either inclusion or exclusion.

While an official designation for a THOW (which may be called a Movable Tiny House in future code proposals) doesn’t exist, common IRC standards and the Tiny House appendix may be utilized during design and construction as best practices providing some “relief” from IRC codes. 

Key Takeaways:

1. As is typical, the Tiny House appendix refers to other codes within the IRC.
2. Proposal for the appendix included downscaled components using ANSI 119.5 (PRMV) as reasonable precedent for “safe alternative dimensions” for architectural elements including lofts, ladders to lofts, ceiling heights below lofts, and stairway treads and risers.
3. Tiny house companies may adopt and promote use of IRC and the Tiny House appendix for design, planning, construction, inspection, and compliance certification.
4. Use of chassis as foundation in a “Movable Tiny House” may leverage IRC R104.11 for “Alternative materials, design and methods of construction and equipment.”

THOW Code & Inspections

Basic Definition: N/A – Tiny Houses on Wheels remain unregulated.

Currently, there is no uniform code that is accepted by any known government entity or officially recognized standards and certification body for the construction of a Tiny Houses on Wheels (THOW). There are, however, inspection programs available for both DIY and professional THOW builders. The most recognized include (listed by founding date):

RVIA (Recreational Vehicle Industry Association) – RV Manufacturer Members

PWA (Pacific West Associates) – RV/THOW; DIY, Pro Builders, and RV Manufacturer

NOAH (National Organization of Alternative Housing) – THOW; DIY and Pro Builders

The differences in these organization’s use of code sets, inspection processes, recording methodologies, and pricing models are somewhat similar, with varied nuances that remain a hotbed of argument and debate.

Key Takeaways: 

1. Manufacturing facilities are certified by RVIA, PWA, and others in the RV industry.
2. PWA and NOAH offer certification programs for DIY and pro builders of THOWs.
3. Individual unit certification using prescriptive standards provides consumer confidence and added assurance that lead to growing support of THOWs by lenders and insurers. 
4. Self-certification programs may use industry guidelines, RV codes, and residential codes as the basis for individual unit certification without receiving recognition by select industry associations, recognized standards organizations, and/or official government entities.
5. Not building to code and forgoing the use of tiny house inspected is akin to the term:
   “Skip and go naked.” 
6. And “Skip and go naked” sounds like such a happy place!

A Little Argument for Tiny Houses 

In the above, I have worked to the best of my ability to report the bits of information as they relate to construction codes, their parameters, and an application to Tiny Houses. Here are my opinions.

I support the need for building codes, independent inspections, code inspector accreditation, and individual dwelling unit certification. Further, I believe that Tiny Houses are unique in their construct, and do not fit neatly within the parameters defined by the existing code sets:

IRC – Residential construction of site-built structures used as dwellings.

HUD – Manufactured homes of 320 sqft or larger as factory-built dwellings.

RV – Motorhome and trailers 8’-6” or less in travel mode for temporary recreational use.  

PMRV – Park model trailers larger than 8’-6” or more in travel mode for recreational use.

To date, our greatest hope is the Tiny House codes recently accepted into the IRC. While working within the confines of the IRC and its application to site-built homes, these codes take into account the unique needs of design for small spaces, sustainable building applications for material savings and lessened site impact, as well as ongoing energy efficiency. 

Further, by lowering the size of our homes, we are free to exercise the option — what I believe is our right — to significantly lower our “carbon footprint” through the construction of Tiny Houses. Additionally, the makeup of our economy and changing employment roles reasonably requires a solution to “home” for families and individuals who move frequently. 

I like to play fair, and uphold the rights of choice for others to purchase large homes with lavish amenities in gated communities with strictly enforced homeowner’s associations. For those of us embroiled in the advancement of the Tiny House Movement, the unique use of Tiny Houses as permissible residences provide many advantages over large homes. 

Final Notes 

In the words of Shakespeare:

“A law by any other name would still be painful when one is caught violating it.”

Standards, codes, and requirements are in place for the greater good. While strong opinions and disinformation perpetuate cycles of uncertainty, frustration, and angst, let us maintain a positive outlook, and continue working together to:

• Thwart fear with courage
• Offset uncertainty with clarity
• Overcome doubt with confidence

For my part, I am merely one of many tiny house advocates working hard to help establish protocols that lawfully defend our right to legally reside in tinier-than-typical small spaces that remain safe, efficient, and affordable. 

Additionally, my personal experience is wholly U.S. based at the municipal, state, and national levels while working with housing directors, zoning officials, and code enforcement officers. The information included here is specific to the U.S., though should be reasonably applicable to tiny house construction and habitation in other parts of the world. At least that’s my hope.

And, of course, every body of information contains errors and omissions, so please pardon my mistakes, and understand that any omissions are oversights without bias for personal gain. 

In the end, and as always…