Single Site Affordable Housing Best Number of Residents

February 21, 2022 Post a Comment

This page offers an introduction to many types of housing and some building techniques that can be used in your toolkit to create more housing affordability in your jurisdiction.

It is part of MRSC's series on Affordable Housing.

Overview

Making housing affordable ordinarily comes down to two variables: size of the home and the cost of materials used to create the abode. Advancements in off-site construction and mass timber tin can make housing more affordable likewise as lead to innovations in small living. All structure in Washington State must follow edifice standards developed past the State Building Code Council, including a Building Lawmaking (2018) and a Residential Building Lawmaking (2018). All housing types and techniques mentioned beneath are currently immune by Washington State edifice standards.

Affordable Housing Types and Models

Affordable housing types are those considered to be affordable in the local real estate market. Many of these housing types have a smaller footprint, which helps to keep structure costs low. Similarly, advancements in off-site construction and mass timber tin make housing more affordable as well equally lead to innovations in small living.

This folio reviews several affordable housing types, including micro units, co-living, single-resident occupancy, mobile homes, tiny homes, tiny homes on wheels, and accessory dwelling units. Micro units, co-living, or unmarried-resident occupancy (SRO) tin often exist found connected to or inside existing multi-person buildings or a formal shared living space. Accompaniment dwelling units (ADU) can be either attached or detached to another dwelling, while tiny homes, tiny homes on wheels (THOW), and mobile homes tin be considered as a detached, contained blazon of housing.

Micro Units, Co-Living, and Single-Resident Occupancy

Micro units are small units, mostly measuring nether 400 foursquare feet, that are included as part of a multi-unit building. Some micro units include their ain private bath and a kitchenette whereas others are simply a private living space with shared kitchen and bathrooms. Other units be somewhere forth this spectrum. No matter the layout, these units are generally created in urban development areas, mixed-use zones, or along transit routes to create density and affordability for unmarried residents or small-scale families. Many cities in Washington have begun to allow this blazon of development. MRSC has created a downloadable nautical chart with some examples of local regulations related to tiny apartments/ micro units.

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These units can also be referred to as: "micro-apartments," "small efficiency home units," "microhousing," "apodments," "residential suites," and "co-living apartments," all with similar requirements and regulations. In that location is no agreed-upon definition or regulation standard statewide, and non all municipalities specify size limits, just these apartments tend to be betwixt 120 and 400 square anxiety.

In some municipalities, small apartments that practise not have a individual bathroom and/or kitchenette are regulated under congregate housing or single-room occupancy (SRO) regulations. This blazon of housing generally includes a private bedroom fastened to a hallway with shared communal bath, kitchen, and living facilities While the line between micro units and single-resident occupancy (SROs) is thin, in that location are some differences:

Micro units (i.due east., micro-apartments, co-living, apodments, etc.) are attached to a multi-unit development and may or may not offer completely individual living spaces, including a bathroom and/or kitchenette.
Single-resident occupancy (SROs) are units where each person living onsite has private living quarters just shares a bathroom, kitchen, and other communal spaces.

Sample Micro Unit, Congregate, and SRO regulations

Seattle
- Municipal Code 23.84A.032 — Defines congregate residence as rooms or lodging for ix or more non-transient persons.
- Manager's Rule 9-2017 — Sets forth minimum room size and other technical requirements for micro units.
Olympia Municipal Code Ch 18.02 — Defines SRO as a room with a shared bath and other communal spaces.
West Richland Municipal Code Ch. 17.09.050 — Defines SRO as rooms with no cooking facilities for three or more non-transient persons.

Resources for Micro Units, Co-Living, and SROs

Urban Land Institute: The Macro-Views on Micro Units (2015) — Compares different definitions of micro-apartments nationally and worldwide; contains lots of smashing examples.
OneSharedHouse 2030 — This research projection shares what people say the wanted (and did not want) in a co-living facility
ShareNYC (2018) — The Metropolis of New York launched ShareNYC, an initiative aimed at creating co-living and other shared housing developments to meet housing needs.

Accessory Dwelling Units

Many cities and counties in Washington allow and even encourage the development of Accessory Habitation Units (ADUs), which are pocket-size, cocky-contained residential units located on the aforementioned lot equally an existing unmarried-family home. While the high toll of constructing a detached ADU may foreclose it from existence considered "affordable housing," allowing for a separate, fastened ADU within an existing residence will likely issue in a new, more affordable housing unit. For more information, see our page on Accessory Dwelling Units.

The prototype below shows the different types of ADUs, from detached to fastened to (or located inside) the principal domicile.

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Manufactured Homes and Mobile Domicile Parks

The requirements for a "designated manufactured home" is provided for in RCW 35.63.160, including that a designated manufactured habitation must include at to the lowest degree two sections. Further, when installed, the state requires that a manufactured home be attack a permanent foundation in the manner specified by the manufacturer. Local governments can regulate the siting of manufactured homes and mobile home parks. Skagit County's handout on Installing Manufactured Homes offers instructions on site preparation and requirements for the county.

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Manufactured/mobile homes and mobile home park zones tin offer affordable housing in any local jurisdiction. However, rising country values and new development can force many of these parks to close. Some municipalities, such as Bothell and Kenmore, have instituted regulations for the purpose of preserving mobile abode parks in their jurisdictions:

Bothell Municipal Code Sec. 12.04.100 — Mobile Domicile Park Overlay zoning classification is used to retain mobile abode parks as source of affordable single-family and senior housing. Applied to existing parks that contain rental pads. Limits development unless a comprehensive plan subpoena is adopted.
Kenmore Municipal Lawmaking Sec. xviii.50.140 — Sets standards for existing manufactured housing communities. Specifically, states that they shall continue to operate co-ordinate to the standards that were in place at the time that the parks were canonical. Sec. eighteen.l.150 outlines development standards for new manufactured domicile communities. Notably (B)(iii) states that they shall be eligible to achieve maximum density permitted by providing the affordable housing benefit.

Resource for Mobile Dwelling house Parks

Seattle Journal for Social Justice: Move it or Lose it (2018) — Discusses closures of mobile home parks that results from rising land values and development, all-time approaches for maintaining parks every bit housing options, the legal requirements for redevelopment, and more than.
University of Georgia: Home Sweet Mobile Park: Developing a Historic Context for a Modern Resource (2012) — Chapter 2 covers the origins of trailers and mobile homes, and the design of trailer campgrounds and mobile domicile parks going back to the early 1900s. Chapter 3 covers the evolution of regulations over time, including regulation of home dimensions, revenue enhancement, pertinent zoning and building codes, other regulatory barriers, and recommended best practices through land evolution standards.
MRSC: Local Country Utilize Regulation of Manufactured Housing (2018) — Provides an overview of regulations on mobile homes and manufactured housing, including details on the passage of new legislation in Washington Land over time, legal cases, state statutes, and numerous samples of local codes.

Tiny Homes on Wheels and Tiny Houses/Pocket-sized Houses

When nigh people talk nigh "tiny homes," they are likely to exist thinking of a Tiny Home on Wheels (THOW). THOWs are designed to be hands transported from location to location, are often custom congenital, and usually brand provisions for living, sleeping, cooking, and sanitation. But they are not synthetic to be used as a permanent dwelling house unit and usually cannot meet Building and Residential code requirements (i.e., IBC/IRC). Instead, they are more than like Recreational Vehicles (RVs) and designed to be used as temporary living quarters for recreational camping, travel, or seasonal use.

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Photo courtesy of Portland Culling Dwellings.

In comparison, a tiny house/small house volition vary in size (typically less than 600 sq. ft.), is built on a foundation, and has been constructed to meet Building and Residential Code (i.e., IBC/IRC) standards for a permanent abode unit of measurement meant to be lived in year-circular. Within urban areas, tiny houses/modest houses are sometimes used as a Detached Accompaniment Dwelling house Unit (DADU) and located in a lawn of a larger primary residence. However, they accept also been developed in clusters (every bit a stand-solitary customs) or used as a primary residence in a rural or a rural/suburban setting.

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In 2019, the Washington State Legislature passed ESSB 5383, which expanded the potential for construction of tiny homes on foundations and was intended to make information technology more feasible for these structures to be used as a primary residence. Tiny homes on foundations are besides being used in cities and counties to temporarily business firm homeless individual. This sometimes leads to the creation of tiny dwelling house villages (see the Low Income Housing Institute, which operates several villages in Seattle) where at that place are shared cooking and sanitation facilities merely each resident has an independent, tiny habitation residence.

Sample Tiny Business firm/ Minor House Regulations

Clark Canton Code Ch. 40.100.070 — Includes tiny houses in its definition of unmarried-family dwellings every bit a detached dwelling of less than 150 foursquare feet, constructed or mounted on a foundation and connected to utilities. Clark Canton groups tiny houses with other single-family unit homes, with both housing types existence permitted in similar zones.
Langley Municipal Code Ch 18.22.290 — Allows for the creation of tiny homes clusters surrounding a common open infinite, subject to specific standards.

Sample THOWs, PMUs and RVs Regulations

A park model home/unit (PMU) is built according to Recreational Vehicle (RV) industry code and follows the same rules for quality and design. However, information technology is mounted on a trailer and, like RVs, a PMU is designed to provide temporary adaptation for recreation, camping, or seasonal use. Many local governments will regulate PMUs in the same fashion that they do RVs.

Chelan Municipal Code Ch. 17.13.050 — Conditionally allows RVs and PMUs as emergency and transitional housing
Ocean Shores Municipal Code Ch. 17.25.020 — Permits recreational vehicles, including PMUs and THOWs, in the R-6A zone, which is designated for manufactured and trailer homes.
Skagit County Municipal Code Ch. 14.16.710— Specifies that no recreational vehicle, including park model trailers, shall be allowed every bit an accompaniment dwelling unit.
Sultan Municipal Code Ch. 16.46.070 — Sets standards for mobile dwelling house (including tiny home) parks that treats tiny homes as a THOW instead of a permanent structure on a foundation.
Whatcom County Municipal Code — Several sections, includingCh. twenty.24.130, Ch. 20.22.130, Ch. twenty.72.130, and Ch. 20.36.130, authorize park model trailers and other types of RVs to be located in a variety of residential zones.

Innovative Techniques to Build Affordable Housing

Innovative edifice techniques can also lower the cost of constructing new homes. This page inclues information on modular housing and mass timber/cantankerous-laminated timber (CLT), two innovative techniques.

Modular Housing

Modular housing is factory-congenital housing that is transported and assembled onsite. Modular construction, also known as off-site structure, has historically been used for single-family unit housing, and more recently, it has too been used to construct multi-story commercial buildings (especially hotels) and multi-family housing.

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Under optimal conditions in that location are a multifariousness of benefits to manufacturing plant-built modular housing:

It can reduce costs by shortening construction timelines, leading to faster "time to market" (versus traditional construction).
It tin create efficiencies, resulting in a lower sq. ft./unit cost and reduce project costs.
Information technology provides safer working conditions, every bit compared to traditional, on-site construction.
Modular housing factories tin be operational year-circular while traditional construction is limited by seasonal atmospheric condition.
Modular housing factories are more cost efficient due to streamlined assembly, improve quality control, and more than efficient use of materials, leading to leading to less waste, which also makes it an environmentally sustainable approach.
Modular housing can exist congenital simultaneously during the site preparation phase of construction (i.e., instillation of utilities, grading, building the foundation).

With modular housing being a relatively new construction method, it is not widely used in the State of Washington, although there are examples. This is due to several factors, generally involving limited knowledge and experience working with this method. This general lack of understanding about modular construction extends from developers and contractors to government staff and lending institutions.

Recommended Resources for Modular Housing and Construction

American Institute of Architects: Pattern for Modular Structure: An Introduction for Architects — Offers instance studies and links to specific projects.
Modular Building Found: Inquiry, Whitepapers, and Studies — Offers several whitepapers about modular housing address construction options, safety, design considerations, and more.
Northgate Industries Ltd: Prefab, Modular, and Off-Site Construction - Are they the same? (2018) — A brusk but skilful explanation of the overlapping nature of these three terms.
Sightline Found: Modular Construction: A Housing Affordability Game-Changer? (2019) — Reviews modular structure options in the Puget Sound and the companies behind these options.

Mass Timber

Mass timber is a grouping of framing styles typically categorized by use of solid, large wood panels for wall, floor, and roof construction. This category includes multiple products, including cross-laminated timber, nail-laminated timber, glued-laminated timber, dowel-laminated timber, structural composite timber, and wood-physical composites. Mass timber construction offers a lighter carbon footprint, making information technology a greener option than traditional construction methods, besides every bit being an efficient and safe method for use with large construction projects. It too offers cost savings over traditional construction methods for medium to high-ascension buildings by using woods framing instead of the more expensive concrete and steel framing.

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Photo courtesy of LEVER Architecture.

The Washington State Building Code Council made changes to allow for tall wood and mass timber construction, which went into event in July of 2019, opening the door for mass timber construction projects. Cities, including the City of Seattle, have begun making changes in their building code to let for this type of construction.

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