I’ve compiled an early proposal for a demonstration ordinance that could be adopted at the municipal level to make the tiny house village an acceptable residential land use—inspired primarily by cottage housing ordinances around the Seattle area. This would allow the housing option to be more readily deployed, and in a variety of styles (i.e. low-cost or upscale). In essence, it is a hybrid of both single- and multi-family housing along with the addition of a social dimension that has gone desperately missing from those conventional options.
Tiny House Development (THD) Demonstration Ordinance
1. To increase housing diversity in ways that are compatible with existing residential zones
2. To promote housing affordability and sustainability for all income levels by encouraging smaller homes
3. To allow for a limited number of regulated THD demonstration projects
4. To set forth a review process and general parameters for THD demonstration projects
5. To evaluate demonstration projects to inform the adoption of a permanent ordinance
1. Provide an opportunity for the development of small, detached housing clustered around common open spaces
2. Combine character of single family housing with affordability and density of multi-family units
3. Increase affordable housing options for one and two person households and small families
4. Reduce per unit development costs of conventional low-income housing developments
5. Permit THDs in residential zones
6. Provide opportunity for infill development (clusters of tiny houses can fit on standard residential lots)
7. Allow for higher density standards in exchange for reducing impact by limiting house size
8. Create a range of affordability by allowing for varying levels of support from common kitchen, bath, and gathering facilities
Development Standards (preliminary):
1. Redefining Density: Housing developments may increase the per unit density standard of the underlying zone by 50% when in compliance with the standards set in this section.
2. House Size Limits: The maximum allowed gross floor area is 950sf per unit. The maximum gross floor area for the ground floor is 750sf per unit.
3. Common Open Space: cottages fronting at least two sides. Each unit must have x amount of common space. Reduced in-unit kitchen/bath requirements if supported by on-site common facilities.
4. Parking Standards: 0.5 parking spaces per dwelling if within 0.25 mile of transit stop.
5. Non-conforming Structures: Existing structures that are non-conforming to the standards for a THD are permitted to remain, provided that the extent of the non-conformity shall not be increased.
Precedent: Kirkland, WA—Cottage Housing Ordinance:
1. The City of Kirkland began review of cottage housing under an "Innovative Housing Demonstration Ordinance" in 2002, with similar goals to the ones set forth above
2. An interim ordinance was adopted to test the idea of cottage housing before adopting a permanent ordinance, and a formal evaluation was completed in 2006
3. The demonstration projects were successful in implementing a new and smaller housing option, though the actual affordability of the housing was questioned. The projects became highly desirable places to live.
4. A permanent Cottage Housing Ordinance was adopted and has been listed as a best practice by HUD: http://www.huduser.org/portal/casestudies/study_102011_2.html
5. Cottage Housing has been adopted in several cities in the Seattle area, which has informed this resource: “Cottage Housing in Your Community: A guide to drafting a Cottage Housing Ordinance"
Interpretation of Minimum Area Standards as defined by International Residential Code:
The size of the housing units would be limited to the minimum area standards set by the building code. This includes:
1. R304.1 Every dwelling unit shall have at least one habitable room that shall have not less than 120 square feet of gross floor area**
2. R304.2 Other habitable rooms shall have a floor area of not less than 70 square fee (except kitchens)
3. R304.3 Habitable rooms shall not be less than 7 feet in any horizontal dimension (except kitchens)
4. R304.4 Portions of a room with a sloping ceiling measuring less than 5 feet between floor and ceiling shall not be considered as contributing to the minimum required habitable area for that room.
5. R306.1 Requires that every dwelling have a water closet, lavatory, and bathtub or shower (which could be as small as 18sf while still meeting spacing requirements in Section 307)
6. R306.2 Requires that every dwelling have a kitchen area with a sink
7. There are no minimum area requirements for a bathroom. There are space requirements for the various bathroom fixtures, which could be accommodated in 18 square feet.
** The provision for one room of at least 120sf has been eliminated in the 2015 International Residential Code
Conclusion: There is no requirements that the sleeping area or kitchen has to be in a separate room, and with the 120 square foot requirement removed, the legal permitted limit for a tiny house could be as small as 88 square feet (70sf room + 18sf bath)