The "tiny home" or "small house" has been a part of American life ever since the shotgun shack of the 1930s. But what turned the tiny home into the Tiny Home Movement was the Great Recession of 2007, when economic pressures made a lot of new homeowners look seriously at tiny homes (meaning typically less than 400 sq. ft. of floor space) as an affordable housing alternative, and with it a lifestyle that stressed simplicity, frugality and sustainability. The movement later received a boost in public awareness thanks to reality shows such as Tiny House Nation and Tiny House Hunters.
The economic downturn caused by the coronavirus pandemic, coupled with skyrocketing real estate prices in some parts of the country, has caused a resurgence of interest in tiny homes. But tiny homes have always faced special challenges when it comes to code considerations.
As per the 2018 International Residential Code, a tiny home lacking the necessary amenities required for a dwelling needs to be on the same lot as a building that does (with the tiny home considered an Accessory Dwelling Unit or ADU). Since many tiny homes are designed to be mobile, it can sometimes be difficult for owners trying to change location to find a jurisdiction that will accept them. Adding to the difficulty are plumbing considerations specific to tiny home design.
Enter the Code Council
Ryan Colker is VP of Innovation for the International Code Council, where he serves as director for ICC's center focused on energy resilience and innovation. Along with energy efficiency and climate risks, some of the topics the Code Council is addressing year round are off-site construction—which includes tiny houses—and aspects of integrating codes with the digital design process.
"We still have a lot of the chronic issues around housing availability and affordability," Colker says, "and people are looking for a wide variety of solutions, tiny houses being one of them. We’ve certainly seen an increase in the conversation around accessory dwelling units (ADUS) and many of those can actually be classified as tiny houses. We may not deal with tiny houses specifically, but a lot of the surrounding issues, similar conversations can pull in tiny houses as well."
One of those issues is certainly off-site construction, often used in tiny home construction, but also being widely adopted across the construction industry. Working off site confers a lot of advantages, including a higher degree of worker safety, less waste, and greater efficiency.
Colker also notes that it's often easier to hire people to work on the floor of a fab shop than out on the job site. "I mean, there are people who don’t want to be on the roof of a skyscraper in Minnesota in the middle of winter, but will certainly work in a controlled factory where the most they have to climb is a six-foot ladder."
Recognizing the growth in off-site construction, the Code Council released two new standards this pastSeptember: Standard 1200 and Standard 1210. "Standard 1200 focus on the broader off-site construction process," Colker says. "What are the key parameters that designers and manufacturers should observe to ensure compliance with the code? Standard 1210, which is the companion to that, is how the code official and the regulatory community should deal with off-site construction, and how plan review and inspection should work. So those two set the general framework."
Colker stresses that off-site construction can range from an individual, one volume component to a high-rise apartment or hospital consisting of several inter-connected modules. In the "multiple volumetric module context," understanding the connections, from module to module or panel to panel, with MEP systems is an area that can present significant challenges for designers, installers, and inspectors. That is just one component of what Standard 1210 will be addressing.
Another component will be identifying opportunities for meeting requirements in the International Energy Conservation Code, or the International Plumbing Code, in a factory setting.
"It may be easier to run some tests at the individual component level rather than doing it all on site once everything gets brought to the site and assembled," Colker explains. "So that’s the sort of thing the development committees will be looking to. There may be opportunities, particularly relevant to tiny homes, where you have leakage testing, or plumbing system testing at a systems level, where it may be more efficient than trying to do it on the final job site."
Plumbing & Fixtures
When it comes to graywater and blackwater, traditional concerns around contamination and human health are paramount. "Our main direction to folks are, consult your local health department for any sort of regulations," Colker says. ICC has the International Private Sewage Disposal Code, which lays out a lot of the requirements around private sewage disposal and how to design, operate and maintain systems to address those sorts of challenges.
Since many tiny homes are not connected to a municipal sewage system, composting toilets and even incinerating toilets can be fairly common. Fortunately, ICC addresses composting toilets in NSF Standard 41 for “Non-liquid saturated treatment systems.” On the incinerating side there’s a CFA/ANSI Standard for gas-fired incinerating toilets, V21.61, and also an NSF protocol for electric-fired incinerating toilets: P157. "The protocol is not to the level of a standard," Colker says, "but at least there’s some level of guidance there. Then the CSA Standard is referenced in our International Fuel Gas Code."
Residential Code Still Applies
Colker emphasizes that there are general requirements within the residential code for anything that could be classified as a permanent or primary residence, and those criteria would apply to tiny houses as well. Of course, there are certain things you would do in a single-family, site-built house that might not be practical in 400 square feet.
"We’re talking about stairways or ladder or use of lofts, those sort of things," Colker says. "We do have Appendix AQ, starting with the 2018 IRC, to provide some of that flexibility to folks that are doing tiny houses. I think it’s really important to note that the criteria exists for tiny houses to deliver the same level of safety and efficiency that we would expect of any other housing solution. Those resources are really valuable, both to the contractor and manufacturer community, but also to policy makers as well as consumers who are considering purchasing a tiny home."