RV Certified Or A Licensed Contractor

Tiny Portable Cedar Cabins Partners With Builders That Are Either A Licensed Contractor Or They Use A Third Party Inspection And Certification Agency to adhere to all life and safety standards. Washington state does not use third party agencies, the approval process is through Labor and Industries.

Washington State Department Of Labor And Industries

A tiny house is a dwelling that may be built on wheels and is no larger than 400 square feet, including a kitchen, bathroom, and sleeping/living area, and must be built to the Washington State Building Code. The approval process for a tiny house depends on where it’s built.

On this page, you can determine whether you need approval of construction plans and inspections from L&I or the local building department where the house is being built. 


Washington State Labor & Industries

RADCO A Twining Company

RADCO, founded in 1967 is recognized as an independent third-party testing laboratory (TL-209), listing agency, and a Quality Assurance Inspection Agency (AA-650) by IAS (International Accreditation Service, Inc.). RADCO is also nationally recognized as a Design Approval Inspection Agency (DAPIA) and Inspection Primary Inspection Agency (IPIA) for the Manufactured Housing program (HUD) and can provide DAPIA and IPIA certification for any state modular program that allows a third-party to do so.

RADCO is fully recognized as a Third Party plan review and inspection agency for factory built (modular) residential and commercial structures by the IBC (Industrialized Building Commission), and all states with such programs.

RADCO is accredited and recognized by many state and national accreditation bodies. RADCO is also a member of several industry organizations, including ICC, IAS, The Modular Building Institute, NMEDA and the Manufacturing Housing Institute.


RADCO A Twining Company

Pacific West Associates

Pacific West Associates, Inc. which is an accredited third party agency that has been recognized in the industry for over 30 years. PWA is composed of licensed electrical, mechanical, structural and forensic engineers. The  evaluation and certification staff meet the requirements of the ASTM (American Society for Testing and Materials) E699-16, which​ is for agencies involved in testing, quality assurance, and evaluating of manufactured building components.

Services include DIY Built, Manufactured Built and Consultations. Chuck Ballard is the Director Of Standards for THIA  and is a principle member of the following: Principle Member of the NFPA 1192 Standard On Recreational Vehicles Principle Member of the NFPA 1194 Standard On Recreational Parks And Campgrounds Principle Member ANSI A119.5 Park Model Recreational Vehicle Standard Principle Member ANSI UPA (Uniform Plan Approval) Principle Member ANSI/RVIA Low Voltage Standard More Details

Pacific West Associates


NTA is a third party agency that provides product testing, inspections and certifications, engineering, and plan review, as well as independent quality and standards compliance verification for many building products. Our professional services have value to residential and commercial builders, code officials, and manufacturers and suppliers throughout the building industry. NTA serves our clients with a nationally recognized and accredited, third-party testing laboratory to assist in the development of new and innovative products.

We’re proud that our laboratory and product certification services are accredited by A2LA.  NTA, Inc. certifies compliance of each unit to ANSI A119.5 standard. Since we are accredited by the Standards Council of Canada (SCC) to certify products to CAN/CSA Z241, your next park trailer project can meet or exceed all appropriate standards and certifications, whether it is intended for use in the United States or Canada.

NTA is fully accredited to the same ISO 17065 standards as other, similar third-party agencies, ensuring that both consumers and regulatory agencies are confident in our product certifications.

The International Code Council announced that it has acquired NTA, a leading provider of testing services, product certification, inspection, engineering, off-site construction on July 12th, 2019. The name was changed to ICC NTA after the aquisition.



Designated by HUD as both an IPIA (Inspection Primary Inspection Agency) and a DAPIA (Design Approval Primary Inspection Agency), PFS TECO is your one-stop shop for both plan review and inspection of HUD-code manufactured housing. We have five regional offices throughout the United States, allowing us to have professional inspection staff within a small distance of almost any manufacturing facility in the country.

PFS TECO is accredited by International Accreditation Service ( IAS ) and meets the requirements of AC98, IAS criteria for inspection agencies, and has demonstrated compliance with ISO/IEC Standard 17020: 2012, Conformity assessment.


California Department Of Housing And Community Development

3rd Party Agencies

The best rule of thumb I use when I am choosing a builder to work with is to choose a builder or 3rd party agency that is recognized and is listed with the California  Department of Housing And Community Development, Codes And Standards Division. Most of the agencies listed have 30 to 80 years expertise in the industry in all aspects of testing, inspection and certification. Los Angeles only recognizes the list above for ADUs and Movable Tiny Homes. See More Below.

A Quality Assurance Inspector ‘Original’ applicant must satisfy all the provisions of ASTM Standard E 541, Part B, 14 and T25, CCR, Chapter 3, Section 4856

Note: ASTM Standard E 541 was withdrawn without a replacement in January 2019.

Withdrawn Rationale:

This specification was initiated to meet the needs of regulatory programs for the certification of manufactured building.

Formerly under the jurisdiction of Committee E36 on Accreditation & Certification, this specification was withdrawn in January 2019 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.

1.4 This specification covers criteria by which the technical resources of agencies, both governmental and private, may be evaluated for their capability to perform the system analysis or compliance assurance function, or combination thereof, in the evaluation and inspection (certification) of manufactured building. Practice E651/E651M may be used for the evaluation of such agencies.

Agencies involved in testing, quality assurance and evaluating building components can be evaluated by using Practice E699.

ASTM Standards

E651/E651M Practice for Evaluating Capabilities of Agencies Involved in System Analysis and Compliance Assurance for Manufactured Building

E699 Specification for Agencies Involved in Testing, Quality Assurance, and Evaluating of Manufactured Building Components

California Approved 3rd Party Agencies

Los Angeles ADUs And Movable Tiny Homes

The City’s Accessory Dwelling Unit Ordinance (Ord. 186,481) was adopted on December 11, 2019 and became effective on December 19, 2019. Among additional matters, it added Los Angeles Municipal Code (LAMC) Section 12.22A.33. This new section of the LAMC includes local development standards and requirements for ADUs, Junior Accessory Dwelling Units (JADUs), and Movable Tiny Houses (MTHs) in Government Code (GC) Sections 65852.2 and 65852.22.

Accessorary Dwelling Unit ( ADU )

An ADU is an attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons and is located on a lot with a proposed or existing primary residence. It shall include permanent provisions for living, sleeping, eating, cooking and sanitation on the same lot as the single family or multifamily dwelling is or will be situated.

Junior Accessory Dwelling Unit ( JADU)

A Junior Accessory Dwelling Unit is a unit that is no more than 500 square feet in size and contained entirely within a single-family residence. A JADU may include separate sanitation facilities, or may share sanitation facilities with the existing structure. The JADU or single-family residence shall be owner occupied.

Movable Tiny House ( MTH )

A Moveable Tiny House is an enclosed space intended for separate, independent living quarters of one family and meets all of the following:

  • Is licensed and registered with the California Department of Motor Vehicles;
  • Meets the American National Standards Institute (ANSI) 119.5 requirements or the National Fire Protection Association (NFPA) 1192 standards, and is certified for ANSI or NFPA compliance. A 3rd  party inspection agency (Design Approval Agency/Quality Assurance Agency) shall certify the MTH meets this requirement (List of approved 3rd party Design Approval Agencies (DAA) and Quality Assurance Agencies (QAA));
  • Cannot move under its own power;
  • Is no larger than allowed by California State Law for movement on public highways; and
  • Is no smaller than 150 and larger than 430 square feet as measured within the exterior faces of the exterior walls.

Development Standards and Requirements

ADUs, JADUs, and MTHs are allowed in any zone that allows for residential use by right. Parking for a newly constructed ADU is not required when it is located within one-half mile walking distance of a public transit. Replacement parking is not required when covered parking is removed in conjunction with the construction of the ADU.

ADUs are required to comply with all applicable Zoning, Building, and Residential Codes. Fire sprinklers are not required if they are not required for the primary residence. Solar panels will be required for newly constructed, detached ADUs.

Permitting Movable Tiny Homes In LA



San Luis Obispo: Tiny Homes

The Community Development Department recently updated its Zoning Regulations which included provisions for Tiny Homes on Wheels in the backyard of on a site with an owner-occupied single-family residence. A single-family residence (Single-Unit Dwelling) is defined as a dwelling unit designed for occupancy by one household which is not attached to or located on a lot with commercial uses or other dwelling units.

Tiny Homes on Wheels are also referred to as Recreational Vehicles (RV) according to the California Department of Housing and Community Development (HCD), and is required to receive certification from the American National Standards Institute (ANSI) and registration by the Department of Motor Vehicles (DMV).

How To Apply For Tiny Homes On Wheels

How Is A Travel Trailer Or A Park Model A Tiny Home?

At this time, there is not one unified industry standard that is recognized for tiny homes on wheels and each jurisdiction, bank, insurance agency, etc… could have a different definition and requirements, including size and if they are allowed as a dwelling. 

Most tiny home builders are building RVs built to the NFPA 1192 Standard or the Park Model Standard, ANSI 119.5  for the ability to have them certified and registered,  to get a Vin number and title.

These standards address all safe health, life, and fire precautions.

The builders most always exceed the minimum requirements of these standards and build to 2 X 4 and 2 X 6 construction, increase insulation values, have 25-year roof warranties, increase truss loads when applicable, and use superior quality materials.

The beauty of tiny homes is they are custom built to order and can be built for all seasons with a focus on durability and longevity. They can also be built to any added requirements of the jurisdiction. 

Always Do Your Own Personal Due Diligence

Always find your legal place to live in a tiny home as your initial investigation and do your own personal due diligence to avoid problems after you buy your home. Please contact me, I would love to work with you and make your tiny home dream come true.


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Founder And President
Tiny House Alliance USA

The Future Of Tiny Is Now!