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Creative Single-Family Infill

While single family only zoning still dominates land use patterns in most places, there are often overlooked and underutilized ways to innovate within this status quo. For example, districts that allow Accessory Dwelling Units (ADUs) provide a runway for creative build-to-rent options in single-family neighborhoods. Through our expertise in zoning, building codes, and development, KUA has formulated strategies to creatively leverage IRC (International Residential Code)-compatible infill to provide attainable housing choices within existing, walkable single-family neighborhoods.

The diagram below is compatible with some single-family-zoned districts in Atlanta. Four “units” on a single-family lot? How can this be? Let’s break it down!

To begin, terminology matters. There are not four Dwelling Units on this lot. There is one primary Dwelling Unit, one Guest House, and one Accessory Dwelling Unit (ADU). These are all permitted by Atlanta’s current zoning code. Atlanta, like many municipalities, allows a primary Dwelling Unit along with various accessory structures in some single-family zoning districts. The key to unlocking attainable housing choices is to better understand the specifics of what type(s) of accessory structures are allowed in which zoning districts.

In recent years, Atlanta’s zoning has been incrementally updated to allow detached Accessory Dwelling Units (ADUs) in multiple districts (R-4, R-4A, and R-5). We’ve written extensively about the specifics of ADUs - see links here and here. What makes things more interesting is that the City still allows a legacy housing option called a Guest House. Additionally, the City allows properties in some districts to have both a detached ADU AND a Guest House provided the property can conform with other requirements like square footage caps and lot coverage limitations. Guest Houses are allowed in all of Atlanta’s single-family districts and differ from ADUs as they are intended for short-term occupation (guests) or live-in help (defined in the code as “servants, watchmen or caretakers”). Guests Houses are not allowed to have “independent cooking facilities,” like stoves. Additionally, the size of Guest Houses are tied to the size of the primary Dwelling Unit, whereas ADUs have a maximum size that is unrelated to the size of the primary Dwelling Unit.

While Atlanta is facing a daunting housing crisis, we see folks being willing to sign an employment contract to be a “watchperson” in return for reduced rent as a reasonable use of a Guest House. This is a straightforward way to offer both workforce housing and compliance with an outdated (and racist) zoning code. Lemons and lemonade, as some might say.

You might notice anther flag in the diagram called out as a ‘Guest Suite’. There is no City definition of this term, but in use a Guest Suite is a semi-independent living arrangement that is part of the primary Dwelling Unit and has its own exterior entry door. Other groups such as AARP call these “Wing Units” in their new publication Discovering and Developing Missing Middle Housing. Like a Guest House, the Suite cannot have “independent cooking facilities” as that would create a second Dwelling Unit per zoning and building code. Though no stove or cooktop is permitted; a kitchenette with a refrigerator, dishwasher, microwave, and even a washer/dryer are all acceptable to include. The City of Atlanta currently requires an internal connection between the Guest Suite and the main living area of the primary Dwelling Unit. There is no explicit zoning or building code requirements for this connection, but this is the current interpretation being enforced.

Another way to conceptualize this approach to Guest Suites is to consider it a precursor to an Attached Accessory Dwelling Unit (AADU). Though current single-family zoning districts do not allow Attached ADUs, we’ve designed Guest Suites to be convertible to an Attached ADU when zoning codes hopefully update to allow such uses.

Lastly, occupancy in a primary Dwelling Unit and Guest Suite are limited by the City of Atlanta’s definition of a family. It is critical to understand those limitations when considering deploying a Guest Suite. They are particularly important for grown children returning to the nest, or an aging parent coming to live semi-independently from their child. They are also much more cost effective to provide than a detached dwelling.

We’ve discussed terminology, now we need to discuss where this approach can be the most effective. This strategy needs to be deployed in walkable neighborhoods where multiple parking spaces are not required for the tenants. One parking space is required for the primary Dwelling Unit, which can usually be taken care of with a driveway. On-street parking can supplement tenants’ parking needs; though we find that many folks living in workforce housing do not own a car.

Lastly, housing choices and placemaking opportunities expand and greatly improve when a project can transition from a single lot infill opportunity to a multi-lot pocket community – see diagram below. A multi-lot solution allows for more creativity with building layouts, allowing for more shared community spaces without disrupting the overall neighborhood fabric.

This strategy is effective for providing attainable rentable housing, but we must note that there are limitations to providing for-sale housing. There is no current pathway to plat these accessory structures separately for sale from the primary Dwelling Unit without a significant rezoning of the property. This rental strategy can work for an owner occupant looking to maximize housing choices for their neighborhood on their property, but we see the biggest potential for leveraging this strategy to be partnerships with nonprofits.

There are many nonprofits in Atlanta that have acquired a range of single family lots over time. Trying to provide affordable housing at a rate of one home per lot is a hard road as it requires a significant amount of outside subsidy per house. Updating the approach to two, three, or four housing options per lot is a game changer. Nonprofits are able to spread fixed and soft costs across multiple units directly resulting in increased affordability. We are partnering with one nonprofit that is targeting 30% of AMI rents for a two-bedroom Guest Suite. That’s $500/month in non-housing speak. These kinds of rents in non-subsidized new-construction are unheard of, particularly in in-town neighborhoods.

While these approaches for expanding housing choices are not feasible everywhere, they provide the opportunity to pilot housing options and creatively rethink what is possible within our current zoning regulations. With such a dearth of attainable housing options and a zoning code rewrite that is still years in the making, we need all the creativity possible. That’s why we want to share this strategy far and wide.

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