Housing shortages have been a huge problem for a lot of cities in the United States and elsewhere in recent years. Cities have scrambled to try to find solutions to that problem, and there may be some results on the horizon. Many cities and states have made it legal to build accessory dwelling units, or ADUs, on backyard land in suburban areas.
At the same time, a growing movement of people has sought to reduce their usage of space and material when considering where they want to live. This has given rise to the construction of what are called tiny houses all over the world. There are some important ways in which these two movements overlap.
What is the difference between an ADU and a Tiny House?
The primary difference between accessory dwelling units and tiny houses is that ADUs are always meant to serve as an additional or second residence on a property, whereas tiny houses can fill a wider variety of roles. A tiny house can also be an ADU, or it can be the only structure on a piece of land, or any number of other possibilities. In many cases, there is a significant amount of overlap between the two concepts, but not always.
Tiny houses are meant to be built in just about any setting. Owners can design them to sit on foundations, or be built on a trailer for higher mobility. More and more places are making them legal to build or park, as long as they conform to the appropriate building or vehicle codes, but they can be sited as easily in an urban environment as in a rugged and forested mountain tract.
Accessory dwelling units are a specific use case, a way to increase the density of suburban communities by adding additional living space. And the object of this is to make housing easier to build, and therefore more abundant, and therefore less expensive.
The overlap is in the fact that a tiny house can be used as an accessory dwelling unit. Wherever ADUs are now legal, the property owner can use any sort of typical tiny house design that meets the specific square footage requirements.
Another important overlap is the fact that both types of housing make it easier to increase the housing supply in general, because they are less expensive to build than traditional homes, and they can be fit into more spaces.
Over the long run, as these movements continue to play out, it is hoped that they will reduce the problems of homelessness in the United States and other places around the world. They are both excellent and affordable ways to help people get off the streets and have a place to shelter and take care of themselves.
So, in a nutshell, almost any ADU can also be a tiny house, but not all tiny houses are automatically an ADU.
The keyword here is “accessory.” An accessory dwelling unit is an addition to a dwelling unit that already stands on a property. Typically, this refers to a single-family suburban home with a backyard.
By contrast, a large component of the tiny house movement is made of people who wish to forgo the typical trappings of a suburban single-family home of any size, and exchange that for a more minimalist sort of living arrangement.
Of course, not all tiny houses are meant for that specific purpose. Some tiny houses are a second home, or a recreational vehicle, to be used as such. Many people buy tiny homes simply for the pleasure of having a motorhome that looks more like a home than a trailer.
Another important aspect of what makes a tiny home a tiny home is the possibility of forming a community of tiny home users. These communities can exist in specific locations such as RV style parks meant exclusively for tiny homes.
There’s a certain sense of camaraderie that comes with adopting such a significantly different lifestyle than most people are accustomed to.
By contrast, living in an accessory dwelling unit is more often than not simply a means to an end, a cost saving measure. The ADU is still part of a pre-existing community which is formed by a larger group of people with more divergent interests.
In summary, an ADU has a very specific purpose, whereas tiny houses offer a much wider variety of possibilities, including satisfying the requirements for an ADU.
What is a Tiny House?
By definition, almost any residential dwelling that is smaller than about 400 ft.² or 37 m² is considered a tiny home. Beyond that, tiny homes come in many different shapes and styles. And there is a significant range in size too, even with that 400 ft.² maximum.
Some of the smallest dwellings that can actually be considered tiny homes are designed to fit in the bed of a pick up truck. These are uncommon, and don’t offer anywhere near the amount of amenities that a larger structure would provide, but with a gym membership and a willingness to eat at restaurants very very frequently, it’s possible.
The largest tiny homes can be built on gooseneck style trailers, and towed around behind powerful trucks. Or they can be built on foundations and look not too dissimilar from bungalows of the style that was popular a century ago.
Most tiny homes tend to be in the range of about 100 to 200 ft.², and likewise are either built on foundations or on wheels. The original tiny homes tended to be in this size range, and built on trailers, with the purpose of enabling a more nomadic lifestyle.
They were very well-suited to single people who love to travel, or young couples without kids. Later on some families learn to make do with a tiny home as a living space for parents and children, though this is less common.
When it comes to the amenities a tiny house provides, it’s possible to fit them out with all the same kind of appliances you would normally expect from a typical house, including hot and cold running water, with a shower and a standard toilet, a functional kitchen with appliances, electrical wiring and gas ranges.
Other tiny homes are designed to provide that kind of functionality and comfort with greater simplicity, using composting toilets, doing away with the refrigerator, and relying on renewable energy sources for power.
Laws regarding ADUs and Tiny Houses
The main factor driving both of these movements has almost certainly been the housing crisis that has been occurring for the past decade or so. As housing costs have gone up, and more and more cities, especially in the western United States, have encountered geographical barriers to continued outward development, people have been looking for ways to get the shelter they need without breaking the bank.
That, too, was one of the original motives for building the first tiny houses. Those pioneers wanted a way to live comfortably, with everything that they truly needed, without taking on massive amounts of debt and risk.
As the crisis has worsened though, governments started to recognize the danger of leaving the housing supply in the hands of local zoning boards and developers alone.
In recent years, Oregon and California have been pioneering places for exploring new possibilities for the densification of cities in a way that would allow more people to be able to afford more homes.
Some of the first tiny houses were built in rural northern California. Many California cities started allowing tiny homes to be built in locations where zoning codes previously wouldn’t have made it possible. Other states soon followed suit, and now there are many places around the country where tiny homes are both accepted and encouraged.
But the tiny home movement hasn’t caught on fast enough to alleviate the housing crisis. Something more had to be done. Some of the California cities with the worst housing crisis started exploring new laws that would permit the construction of accessory dwelling units in people‘s backyards, or the conversion of garages into apartments.
Even these efforts were not fast enough, though, and the central cities couldn’t control the zoning policies of their own suburbs. So they weren’t making a dent in the problem fast enough.
That all started to change in the middle of last year.
Los Angeles, San Francisco, and Other Californian Cities
During the latter half of 2019, the state of California started the process of designing and passing new laws that would supersede the zoning regulations of every city in the state, including those they had already started pioneering the development of accessory dwelling units.
The state laws went over and beyond those original innovations, and mandated that every single family zoning area in every city now had to allow the construction of at least one accessory dwelling unit and one junior accessory dwelling unit, if the property owners desire to build them.
These accessory units are still subject to requirements based on the square footage of the existing home, and local municipalities are still able to make some adjustments to the requirements based on fire safety considerations, for example.
One particular bit of excellent news, though, is that Los Angeles has specifically made it legal to use a mobile tiny home as an ADU. This is an incredibly convenient development that should have far-reaching results.
California’s housing crisis may soon be a thing of the past because of these laws. In the long run, it will still be necessary for cities to be generally re-developed with higher density residential structures, and more walkable neighborhoods, but the state and the big cities have made important steps in the right direction.
Portland
In mid- 2019, Oregon passed a statewide law allowing the construction of duplex housing in every residential area of any city with a population of 10,000 people or more, and four-plexes in any city with more than 25,000 people, as well as any suburb with more than just 1000 people in the Portland area.
This reform in the state’s building codes has more to do with the possibility of re-development of existing suburban areas than mere additions to an existing property. That being said, provisions do exist for the construction of tiny homes and ADUs within the city of Portland, and they can be found here and here.
Seattle
Although Seattle has suffered from many of the same housing crunch conditions as cities in the other western states, it has been somewhat slower to reform its building codes. New construction in the Seattle area has mostly taken the form of new residential skyscrapers clustering around the Amazon headquarters downtown.
Those new towers are convenient for downtown workers, but they have generally been adding to the city’s traffic problems, and they haven’t really solved the problem of housing affordability, especially since many of those towers are designed as luxury units.
Seattle does, on the other hand, make some provisions for the construction of ADUs and tiny homes within its metropolitan area. There are permits required, as in any other location, but it’s not impossible.
Build it!
Whether you’re looking to convert an existing suburban backyard space into an additional living unit, or you’re trying to build a tiny house on a property within city limits, many of these great places along the west coast of the US are making it easier than ever before.
Just always be sure to do careful research, and talk personally with planning authorities, to make sure that your new housing project will go as smoothly as possible!