Tiny Houses – What they are and why they matter

What are Tiny Houses?

Jay Shafer, one of the godfathers of the modern tiny house movement, defines a tiny house as a structure in which all of the space is used well. This is admittedly a vague definition, but it hammers home the point that the concept of the tiny house is much more than the square footage of a particular structure. It’s a way of thinking.

For practicality sake, there are two broad categories of tiny homes: a tiny house on wheels (THOW) and a tiny house that sits on a foundation (which can either be site built or pre-manufactured). Exact size parameters for a tiny house are hard to pin down. Just browsing through the Wikipedia page for “Tiny House Movement” one can find several differing definitions. A popular tiny house website and online resource called “Tiny House Community” has unofficially defined a THOW as “no less than 70 square feet and no more than 400 square feet excluding loft space.” I would amend this definition for THOWs to be no more that 320 square feet of non-lofted space. One reason for proposing this size definition is to limit confusion between HUD (U.S. Department of Housing and Urban Development) regulated manufactured (mobile) housing and modern tiny houses. HUD defines a manufactured home as a structure of at least 320 square feet of floor space. Another reason is that it would be difficult to build a tiny house larger than 320 square feet that could legally be towed by a standard 1-ton truck without a commercial driver’s license (CDL) because of weight restrictions.

In general, one could accurately call any home under 500 square a “tiny house” and be correct.

Permanent foundation homes over 500 square feet, up to about 1000 square feet, may still be referred to as a “tiny house” by some, but the more correct nomenclature would be “small house.” And as long as we’re dwelling on linguistic semantics, very small (under 300 square feet) permanent foundation houses and particularly apartments are often referred to as micro housing whereas their wheeled counterparts have largely co-opted the word tiny. Structures under 100 square feet are sometimes referred to as Nano houses.

Whether they’re referred to as micro, nano, small or tiny, the common thread between most of these structures is that practical multi functional design and quality materials are the first concerns.

The Wind River Bungalow (153 ft²) – A tiny house that houses 2 adults and a large dog


The Gypsy Junker – A 24 ft2 Nano house

I have been asked what makes a THOW different from a manufactured home or recreational vehicle (RV) on more than one occasion. Though the full answer to this question is long and complicated, I will start by saying that the primary difference is that the construction methods, end use, and size parameters of a THOW are vastly different from that of a manufactured house or RV.

Tiny Houses vs RVs

RVs, in their various forms, are primarily regulated by standards set by the American National Standards Institute (ANSI) and National Fire Protection Association (NFPA). The particular codes are ANSI 119.2 / NFPA 1192 for standard RVs and ANSI 119.5 for Park Model RVs. These standards are enforced at the level of the RV manufacturer by private organizations, the largest being the Recreation Vehicle Industry Association (RVIA).

Typical construction practices for RVs are centered around saving weight in favor of portability and lowering production cost. This often means walls are constructed of 2×2” framing material (pine boards) with fiberglass insulation, aluminum or fiberglass exteriors, and thin (1/4”) wood panel interiors. Because RVs and Park Model RVs are explicitly designed for “seasonal use” and expressly NOT designed for permanent occupancy, they are not required to adhere to either HUD or International Building Code (IBC) standards for long-term livability. Read more about that here. While it is common practice to do so, it is illegal to reside in an RV for more than a specific amount of time (usually 90 days) in many municipalities in the USA. Many full time RV dwellers skirt these laws by simply moving their RV every 90 days to a different location, but this shouldn’t be viewed as a permanent solution

By contrast, most quality tiny homes are constructed using IBC standards for permanent foundation home construction with very few exceptions. They are typically built with either 2×4, 2×6, SIP panel or steel stud framing. Often additional bracing at corners is added and siding and roofing is double fastened to withstand sustained highway wind load. Rigid foam or closed-cell spray foam insulation is often used in place of inferior fiberglass batt insulation. Commonly used finishes include tongue and groove pine or bead board interior interiors and wood, wood composite, or steel siding.

Despite the obvious difference in the intended end-use of tiny homes vs RVs AND the marked difference in construction methods, notable tiny home builders are building their tiny homes under ANSI 119.2/ NFPA 1192 standard and getting certified by RVIA for the sake of expediency (it is currently easier to find financing and insurance for an RV than a tiny house). Interestingly enough, RVIA certified tiny homes are sometimes considered a “higher quality” tiny house option by popular opinion, even though tiny home builders that adhere as closely as possible to IBC standards are actually building an arguably better product that is intended for permanent habitation.

Tiny Houses vs Manufactured Housing

Manufactured houses are federally regulated by HUD standards, which pre-empt and negate local IBC codes. In other words, if I buy a manufactured house that is HUD certified, it doesn’t have to pass local IBC inspections. Most builders, appraisers, and authorities consider HUD standards to be inferior to IBC standards and manufactured home values reflect this. Read here for a simple comparison of IRC build homes and HUD built homes.

The simplest reason that tiny houses do not fall under the manufactured housing category and cannot currently be regulated by HUD is that a minimum of 320ft2 of living space is currently mandated for a house to fall under HUD manufactured housing standards. Most tiny houses, by contrast, fall below this 320ft2 size requirement.

Again, despite these clear legal and technical differences, some HUD certified manufacturers are calling their units “tiny homes” as a way of capitalizing on the popularity of the movement.

Tiny Houses as Tiny Houses

Tiny Houses, in essence, are built in a very similar fashion to custom stick-built permanent foundation construction, with additional considerations for wind load. The main difference from their larger permanent siblings is that many happen to be attached to a chassis. Because of this, I would submit that a quality tiny home, from a reputable builder familiar with IBC code, is built to a higher standard than any other available housing type.

It is clear that THOWs don’t cleanly fit the standards of any existing housing type and it is therefore essential that they be regulated on their own merit as tiny houses. The clearest legal path in my view is for THOWs to be considered a new class of single-unit modular construction that is regulated by IBC standards. Many THOWs currently meet these codes in almost every way.

Progress is already being made on this front. In October 2015 a small group of tiny house builders, advocates, and architects presented an amended appendix, RB168-16,

at the annual ICC (International Code Council) public comment hearings held in Kansas City. Changes of this magnitude normally take 6-9 years and several revisions to pass, but because of the overwhelming consensus of the pressing need of regulatory code, the appendix was approved by a majority vote during this first attempt. Read the full appendix with public comment here.

This code does not include THOWs, but it does address most of the problem areas that arise when trying to build a home under 400 square feet to IBC standards. The appendix will officially be part of the 2018 IBC code, but can be adopted at a local level as soon as it gains official approval.

Why tiny houses matter

In the past five years the tiny house and small house movements have grown from a speck on the global consciousness to a movement that has captured the attention of millions of Americans and people worldwide. While it is true that small/tiny houses of various forms have been built since the dawn of man, the modern American small/tiny house movement can be traced back to several key builders and writers of the last 40 years including Lloyd Kahn, Shelter (1973), and Susan Susanka, The Not So Big House (1998). Both of which espoused the virtues of living simply and in a smaller space for various reasons.

The modern THOW movement got started with Jay Schafer and The Tumbleweed Tiny House Company in 1999. He wanted to build the smallest home that could contain everything necessary for a modern human existence. An experiment in minimalism. The problem is that he couldn’t legally build the 96 ft2 house he wanted to build on a foundation in his municiality. So, he put it on wheels to get around zoning restrictions and began living in it, using it as a platform to launch Tumbleweed and champion housing reform and right-sized living.

The tiny house movement grew slowly until the 2008 housing crisis flung the issue of affordable housing squarely into the spotlight. Suddenly the excesses of the American housing dream were in full view and people were looking for alternatives, some by choice and others out of necessity. This put the tiny house movement on steroids and suddenly tiny house building companies, TV shows, articles, websites, and devotees seemed to be sprouting at a frenetic pace. Tiny house popularity, in its current form, has grown as a direct grass-roots response to affordable housing demand and archaic, consumption-based residential zoning and building code legislation.

The figure above is the Google Trends graph showing the increase in popularity of the search term “tiny house” (generally refers to a THOW), represented by the blue line, over time. The red line, for comparison, is the search term “small house”.

There is very little search activity for “tiny house” until near the end of 2004, at which point search activity slowly begins to rise. Some of the first big spikes in popularity occur around the end of 2008 to coincide with the housing crisis. The growth rate picks up after these spikes until an exponential explosion of interest in the term occurs near the end of 2013. Google Trends measures interest in a topic on a relative scale of 0 to 100. The search terms “tiny house”, “tiny houses”, and “tiny house plans” have all been pegged at or near 100 since the summer of 2014; which coincides with the pilot of the first major tiny house reality show, Tiny House Nation.

What are the challenges

That brings us to today. The movement is still growing at increasing speed and is being accepted into mainstream consciousness. Many experts are predicting that the trend is here to stay and will constitute a much larger share of the housing market in the near future. Unfortunately, growth and utilization of tiny houses (especially THOWs) as a viable affordable housing solution is being hampered in several key areas. The most pressing of these roadblocks is centered around zoning restrictions and building code challenges. On the zoning side, there are many neighborhoods and municipalities that have minimum square footage building restrictions and if one chooses to build or purchase a THOW, there are few places to “legally” park your tiny house. The most common question I get as a builder of tiny homes is “Where can I park my tiny house?”. The undefined nature of tiny homes is also a challenge for building code officials who have to ensure that these structures are safe, livable, and build to local standards.

The issue, as you may have guessed, is complicated. The THOW industry is not centrally regulated at this point. Because of this, depending on the location and certifications of the builder, they are considered RVs, mobile homes, park model trailers, or just an undefined load on a trailer. As was mentioned above, THOWs don’t fit cleanly into any of these definitions because they are constructed using traditional housing construction methods, but they are attached to a chassis. This creates a challenge for zoning officials and building codes officials who are trying to fit them neatly into an approved box.

Even though the number of THOW owners grows every day, most municipalities are either ignoring the need for updated zoning and building codes, are unaware of the problem (opportunity), or don’t have the knowledge of resources to make the necessary changes. The number of people who are building THOWs and living in them is increasing rapidly, with no foreseeable end in sight. There is no accurate census of the number of people that live in tiny houses nationally, but I personally know of at least a dozen in the greater Chattanooga area that are living in tiny homes. The question is how will cities, counties, and states deal with the situation moving forward?

Small permanent foundation homes have their own set of challenges even though they are exactly the same as their larger counterparts in every way. One of those challenges is the fact that it gets more difficult to meet the specific IBC requirements the smaller you build, particularly in the areas of head height requirements, loft sleeping areas, egress and minimum room size requirements. As mentioned previously, many of these challenges are addressed in the new appendix RB168-16, and as wonderful as the appendix is, it still requires approval and implementation at the local level.

Another challenge faced by those wanting to build small housing is securing traditional financing for a home that doesn’t fit within typical size parameters. The amount of money that a bank will give an individual for new construction is influenced heavily by appraisals of comparable homes that have recently sold in the area. Because very few homes under 1000 square feet have been constructed until very recently, there simply aren’t actual comparable in many cases. Appraisers are often left comparing high quality, highly efficient, tricked-out new small homes with starter homes build in the 40s and 50s (a period when many small homes where built). This leaves the appraisal far short of what the actual value of the small home should be until actual comparables can be found.

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