1 REINVENTING THE HOME: HOW ACCESSORY APARTMENTS, OR ACCESSORY DWELLING UNITS (ADUS), CAN BE A BIGGER PART OF DC S HOUSING SOLUTION HARRIET TREGONING October 23, 2017
ADUs What Are They? A second, smaller dwelling on the same grounds as a singlefamily house part of the primary structure, attached or detached An apartment over the garage, in the basement, or in an outbuilding Also called english basements, granny flats, inlaw apartments, family apartments, or secondary units
Accessory Dwelling Units Not a new idea!
ADUs New England Converted Farmhouse Hopkinton, New Hampshire Photos: Roger Hawk
ADUs New England Find the hidden ADU in Warner, New Hampshire
Source:OpenScope Architecture for Los Angeles
Seattle
Comprehensive Plan: Accessory Dwelling Units 8 What does the Comprehensive Plan say? Action H-1.5-B: Explore changes which would facilitate development of accessory apartments (also called granny flats or in-law units), English basements, and single room occupancy housing units. Any changes to existing regulations should be structured to ensure minimal impacts on surrounding uses and neighborhoods. Why? Affordability for renters & fixed-income owners Greater independence for an aging population Incremental addition of new residents while preserving neighborhood character Encourages the adaptive re-use of garages & historic carriage houses
Why haven t I heard much about this before? DC has new BY-RIGHT zoning ordinance for ADUs Approx 100,000 lots are in the R zone in DC Could be eligible for an Accessory Apartment Dozens of Jurisdictions around the US have ADU ordinances but Many have not produced much housing Despite being in existence for decades in some cases Source: City of St. Paul
ADUs Oregon Bob Harris www.accessorydwellings.org ADUs in Eugene and Portland, OR Barbara Gundle www.accessorydwellings.org
Benefits of ADUs Increases a community s housing supply without further land development Facilitates efficient use of existing housing stock & infrastructure An affordable housing option for many low- and moderate-income residents Improves homeowner cash flow Helpful to older residents who want to age-in-place Adds housing options in many established neighborhoods Flexible and diverse uses over time and in changing circumstances
Household Size 1950 & 2010 12 1950 2010 Change Number % Total Population 802,178 601,723 (200,455) -25.0% Households - Total 224,142 266,707 42,565 19.0% w/ under 18 yrs 86,275 55,193 (31,082) -36.0% w/ 65 yrs + 18,940 54,391 35,451 187.2% Average HH Size 3.2 2.11-1.1-34.1%
Illustration by Ryan Sullivan of Paste In Place.
So what ARE the rules for ADUs? 14 One ADU allowed by-right in all R zones (except Georgetown R-19 +R-20, allowed by special exception) May be in detached, semi-detached or attached blg No min lot area size to add ADU to existing structure Min floor areas for existing homes to build interior ADUs in many zones (1200-2000SF) ADU may occupy up to 35% of gross floor area of primary dwelling. Owner must occupy one of the units Max occupancy for ADUs in most R zones =3
Prototypes/Test Fits: 15 LIC SIDEWALK 8 SIDEYARD SETBACK 550 S.F. x 2 STORIES = 1100 GSF R-1-A MAX 1104 S.F. KEY R-1-A (3) EX. FOOTPRINT LOT AREA AREA (SF) Zone Minimum 7,500 ADJACENT PROPERTY 115 MAX ALLOWED FOOTPRINT Actual 9,132 Ex. Building Height(40 ft) 23 Ex. Floors(Max. 3 Stories) 1 Ex. Building GSF 3,824 LOT OCCUPANCY AREA (SF) 25 REARYARD SETBACK DETACHED APT Existing Lot Occupancy 2,549 Maximum Allowable Lot Occupancy (40%) 3,653 Remaining for Accessory Apartment 1,104 INTERIOR APT Used in Case Study (Note Two Story Detached Strucutre. This area is Ground plane lot coverage only, Accessory Apartment is 1,100 SF) 550 Remaining Lot Occupancy 554 8 SIDEYARD SETBACK EX. FOR PAVED PERVIOUS AREA AREA (SF) Existing Pervious Area 5,925 80 ADJACENT PROPERTY PROPOSED PAVED Required Pervious Area (50%) 4,566 Exisitng Excess Pervious Area 1,359 Pervious Area Used in Case Study 605 GRAPHIC Remaining Pervious Area in Case Study 754 CALCUATION
Some Hurdles to Surmount 16 Awareness about the potential for an ADU among homeowners Uncertainty is an ADU is legal on MY property? What is the permitting process? Financial feasibility of a legal ADU Concerns about being a Landlord Cost of building an ADU Financing Issues Finding a designer and/or builder Concerns around owner-occupancy rules Ensuring ADU affordability
Today s Workshop Agenda 17 Plenary Sessions: Portland s ADU experience Barriers and opportunities for creating ADUs Permitting and designing an ADU in R zones Concurrent Breakouts #1 Financing an ADU: Costs & financial resources Zoning & permitting for alley lots & carriage houses in RF/RA zones Concurrent Breakouts #2 Aging in Place: using ADUs to create mutual benefits for homeowners & renters Helping homeowners with buying & selling homes with ADUs qend-of-day Report outs and Next Steps with Drinks
Between 2000 and 2015 the District added 100,000 people. People Living in the District 2 900,000 800,000 700,000 600,000 500,000 400,000 300,000 200,000 100,000 0 Highest District Population 1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 Year Total Population as of 2015 was 672,228 Forecasted Growth Source: US Census Bureau and MWCOG Cooperative Forecast
ADUs bring invisible housing to 19 great neighborhoods New hsg construction with untapped financial resources Near places w/transportation choices Innovative bldg types More economically resilient HHs Flexible and diverse use Greater range of affordability