Chapter 18.37
DEVELOPMENT STANDARDS AND DESIGN REQUIREMENTS FOR COTTAGE HOUSING
Sections:
18.37.010 Purpose.
18.37.020 Applicability.
18.37.030 Definitions.
18.37.040 General development standards for cottages (Table 1).
18.37.050 Site requirements.
18.37.060 Building requirements.
18.37.070 Parking and access.
18.37.080 Accessory structures.
18.37.090 Community buildings.
18.37.100 Private and common open space.
18.37.110 Landscaping and vegetation.
18.37.120 Other design requirements.
18.37.130 Ownership options.
18.37.010 Purpose.
The purpose of this chapter is to establish standards for cottage housing development as an alternative housing choice in order to:
(1) Respond to the region’s changing household demographics;
(2) Provide opportunities for more affordable housing;
(3) Encourage creation of functional usable open space in residential communities;
(4) Promote neighborhood interaction and safety through design;
(5) Ensure compatibility with neighboring uses; and
(6) Provide opportunities for infill development consistent with the goals of the Growth Management Act. (Ord. 10-09 § 1 (Exh. A))
18.37.020 Applicability.
Cottage housing developments are allowed in those areas of the City designated DN-MHO and R-18 zones. Applications for cottage housing developments shall be reviewed under the subdivision or binding site plan process set forth in Chapter 17.30 CMC. Where a conflict arises, the provisions of this chapter shall control. (Ord. 10-10 § 3 (Exh. C); Ord. 10-09 § 1 (Exh. A))
18.37.030 Definitions.
“Carriage house unit” means a small residential or guest unit usually located on the second story of a garage or community building, similar to a studio unit suitable for one resident or two guests.
“Community building” means a building owned in common by the cottage housing homeowners, and designated for multi-purpose uses by the cottage housing community. It should be consistent with the design and scale of the cottages, and its use should clearly be accessory to the cottage housing development. Part of the building may be used for a carriage house unit or for storage for residents.
“Cottage” means a detached or attached dwelling that is small in scale and typically no more than one and a half stories in height, and is developed in a cluster.
“Cottage housing development” means a type of development made up of a minimum of four cottages clustered around a common open space with garages and parking located behind or away from the houses. A cottage development may include two-unit attached residences as well as detached cottages.
“Two-unit home” means a structure containing two dwelling units, designed to look like a detached single-family home. (Ord. 10-09 § 1 (Exh. A))
18.37.040 General development standards for cottages (Table 1).
Table 1 provides the basic design standards for cottage housing development in the City of Covington.
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STANDARDS FOR COTTAGES |
CONDITIONS |
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|---|---|---|
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Maximum number of stories |
One and one-half |
The second story shall be no more than .6 of the square footage of the main story |
|
Maximum building height |
18' (maximum of 25' at roof ridge with minimum roof slope of 6:12) |
The ridge of pitched roofs with a minimum slope of 6:12 may extend up to 25 feet. All parts of the roof above 18 feet shall be pitched |
|
Maximum impervious surface percentage |
50% of gross lot area |
|
|
Maximum lot coverage for all principal and accessory structures in development |
35% of gross lot area |
|
|
Maximum building footprint |
1,000 square feet per unit, excluding attached garage |
Two-unit attached structures shall not exceed a building footprint of 2,000 square feet for one-story units, or 1,800 square feet for one-and-one-half- or two-story units |
|
Maximum unit size (total floor area) |
1,600 square feet excluding an attached garage |
Habitable space in a below-grade story (i.e., basement) shall count towards the total floor area |
|
Density |
12 du/ac. See CMC 18.30.060 through 18.30.100 for other density requirements |
See density bonuses for affordable units below |
|
Parking |
1.3 spaces for 1 BR units, 1.5 for 2 BR units, and 1.8 for 3 BR units. E.g., four 1 BR units (x 1.3), six 2 BR units (x 1.5) and two 3 BR units (x 1.8) = 18 parking stalls for 12 units |
Parking requirements for cottages may be reduced if the location of the site is within .3 miles (1,600 feet) of a transit stop. Other parking requirements and reductions specified in Chapter 18.50 CMC apply |
|
Open and common space |
Minimum of 400 square feet per unit of common open space and a minimum of 250 square feet per unit of usable private open space (excluding side setbacks, but may include decks and patios) |
Common space should be in one contiguous area, or no more than two separate areas. Primary entry and patios should be oriented toward open space wherever feasible |
|
Affordability incentives |
See CMC 18.90.030 and 18.90.040 for details of affordable housing incentives. Bonuses of up to one and one-half times base density are possible, or two times base density if all units are affordable |
Under conditions stated in CMC 18.90.030 and 18.90.040, each unit affordable to households earning under 50 percent and 80 percent of King County median income (benefit unit) allows up to 1.5 bonus units. E.g., four affordable units permit a bonus of six units over the base density |
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Green building incentives |
Bonus of one and one-half times base density allowed if cottages and community building are built to LEED Gold, or Built Green™ 4 Star or 5 Star standards* |
Affordability and green building incentives may be combined up to a maximum of two times base density. Note that 4 and 5 Star Built Green™ levels require verification by a third party |
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*See www.builtgreen.net for details of Built Green™ program, and www.usgbc.org for details of LEED program. See note to CMC 18.37.050(2) for example of calculations. |
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(Ord. 10-10 § 3 (Exh. C); Ord. 10-09 § 1 (Exh. A))
18.37.050 Site requirements.
(1) Arrangement.
(a) Cottage housing developments shall contain a minimum of four cottages arranged on at least two sides of a common open space on a minimum lot of 8,000 square feet.
(b) A development may have several clusters with clear separation.
(c) Cottage housing developments should promote a sense of community both within the development and with respect to the larger community. It should not “turn its back” on the larger community. Units along the public right-of-way should have an inviting facade such as a primary or secondary entrance facing the right-of-way.
(d) All other units shall be arranged around the central common area and have their primary entry facing that common space.
(e) Attached structures containing two units shall be allowed as part of a cottage development but they shall be similar in design to the detached cottages. The number of attached units in a development shall not be more than one-third of the total number of units.
(2) Base Density and Density Bonuses for Affordable Units and Green Development.
(a) Cottages shall be built at a maximum base density of 12 du/acre.
(b) Increased density shall be allowed if the units meet certain affordability criteria described in CMC 18.90.030 and 18.90.040.
(c) Under certain conditions stipulated in those sections, each unit affordable to households earning under 50 percent and under 80 percent of median income (known as “benefit units”) allow the construction of up to one and one-half bonus units up to 150 percent of the base density allowed in the zone.
(d) If all the units in the development meet the affordability criteria, then two times the base density is allowed.
(e) Increased density shall be allowed if the cottage development achieves Built Green™ four-star or five-star certification or LEED for Homes certification at the Gold level. One and one-half times the base density shall be allowed for a development which meets either of these standards.
(f) Affordable housing and green building density bonuses may be combined up to a maximum density of no more than two times the base density.*
(3) Clustering. Critical area buffers may count toward the gross lot area, allowing for clustering of development, and providing a maximum of 50 percent of the common open space requirement.
(4) Lot Coverage. Principal and accessory structures in the development shall account for no more than 35 percent of the gross lot area.
(5) Setbacks.
(a) Setbacks shall be 10 feet from the public right-of-way and from the property line.
(b) There shall be a minimum of five feet side yard, allowing a minimum of 10 feet of space between adjacent buildings.
(c) Front and back yards shall be a minimum of five feet from common areas, structures or internal driveway.
(6) Impervious Surface. No more than 50 percent of the gross lot area may be covered with impervious surface. Use of pervious paving materials is encouraged. (Ord. 10-10 § 3 (Exh. C); Ord. 10-09 § 1 (Exh. A))
*A “benefit unit” is an affordable unit. “Bonus units” are the extra units that are added to the base density. (Base density = underlying density in the zone, such as 12 du/acre in DN-7B). Depending on the affordable income level and whether there is a covenant binding the home to 15-year or 30-year affordability, more or less bonus units can be earned, ranging from .75 bonus units (no covenant required) to one bonus unit (15-year affordability) to one and one-half bonus units (30-year affordability). The maximum bonus units earned can be no more than 150 percent of the base density, or 200 percent if all the units are affordable. For green development, the whole development (including all bonus units) must meet the certification requirements. If it does, then 150 percent of the base density is allowed. If the base density is 12 du/acre, then a “Built Green™” development could build up to 18 du/acre. By also building six affordable units with 15-year affordability, the developer would gain six more bonus units, up to the maximum of 24 units allowed (two times base density of 12).
18.37.060 Building requirements.
(1) Building Footprint.
(a) Cottage units shall have a maximum building footprint of 1,000 square feet.
(b) The footprint of an attached one-car garage is not included in this maximum, but shall not exceed 200 square feet per unit.
(c) Two-unit attached structures shall not exceed a building footprint of 2,000 square feet for one-story units or 1,800 square feet for either one-and-a-half or two-story units.
(2) Floor Area. The maximum total floor area of cottage units shall be 1,600 square feet. An additional 200 square feet is permitted for an attached garage.
(3) Building Height. The maximum building height shall be 18 feet, with a maximum of 25 feet allowed to the roof ridge and a minimum roof slope of 6:12.
(4) Stories.
(a) Cottages may have a second partial or full story, providing that the floor area of the second story is no more than 0.6 of the square footage of the main floor. E.g., a cottage with an 800-square-foot building footprint (main floor) could have a second floor of 480 square feet, for a total floor area of 1,280 square feet.
(b) A below-grade partial story may be allowed, but habitable space on that story shall count toward the total floor area of the cottage.
(5) Two-Unit Structures.
(a) Attached two-unit structures should be similar in appearance to detached cottages and have one primary entry facing the common open space.
(b) The number of attached units in a cottage development may not exceed one-third of the total number of units.
(6) Porches. Attached, covered porches are required with a minimum of 64 square feet per unit and a minimum of seven feet on all sides.
(7) Fences.
(a) Fences around dwelling units or on the street frontage shall not exceed 36 inches in height.
(b) Fences along nonfrontage property line shall not exceed six feet in height.
(8) Existing Dwellings on the Site. Existing dwellings may be incorporated into the development as a residence or community building, and may be nonconforming to standards. Noncompliance may not be increased.
(9) Renovation and Expansion.
(a) Renovations shall be in keeping with the size and architectural character of the new development.
(b) A covenant restricting any increases in unit size after initial construction beyond the maximum allowed by this section shall be recorded against the property. (Ord. 10-09 § 1 (Exh. A))
18.37.070 Parking and access.
(1) Parking.
(a) Parking spaces required for a cottage housing development shall be 1.3 spaces for studio or one-bedroom units, 1.5 spaces for two-bedroom units, and 1.8 spaces for three-bedroom units.
(i) This provides for no less than one assigned space per unit plus extra spaces for visitors or second vehicles.
(ii) Since cottages are designed for small households, it is expected that only the larger units (3 BR) would require a second assigned space.
(iii) The parking requirement may be reduced to one space per unit if the location is within .3 miles (about 1,600 feet) of a public transit stop which has a.m. and p.m. peak headways of 30 minutes or less. Other parking requirements and reductions specified in Chapter 18.50 CMC shall apply.
(b) Parking and/or garage structures shall be located behind or to the side of the residential area and open space. When feasible they should be accessed from the back of the cottages.
(c) Parking areas and garages shall be screened from common space and public streets by landscaping or architectural screening.
(2) Shared Access and Connectivity.
(a) Whenever possible, shared access with adjacent properties shall be encouraged, and in some cases, it shall be required.
(b) The site shall be designed for future connectivity with adjacent lots. (Ord. 10-09 § 1 (Exh. A))
18.37.080 Accessory structures.
(1) Accessory structures such as garages, carports, storage or tool sheds shall not exceed 200 square feet per unit, or 1,000 square feet per structure for a shared garage providing space for up to five vehicles. More than one such structure is allowed proportionate to the size of the development and number of parking spaces required. Storage space may be included in a garage structure, but vehicle space may not be used for storage or uses other than parking.
(2) The design of garages, carports, and other accessory structures must be similar or compatible with that of the cottages in the development. (Ord. 10-09 § 1 (Exh. A))
18.37.090 Community buildings.
(1) Uses.
(a) Community buildings are intended as an amenity for the use of the cottage housing residents and to help promote the sense of community. They may include a multi-purpose entertainment space, a small kitchen, library, or similar amenities.
(b) Guest quarters, storage space, or a carriage unit could be included as part of a community building.
(2) Design.
(a) The community building should be of similar scale, design, and height as the cottages, with a maximum footprint of 1,000 square feet and with the second floor not to exceed 0.6 square footage of the first floor.
(b) Commercial uses are prohibited in the community building. Day care I may be allowed if all building code and health code requirements are met. (Ord. 10-09 § 1 (Exh. A))
18.37.100 Private and common open space.
(1) Common Open Space.
(a) Common open space is a defining characteristic of a cottage housing development. A minimum of 400 square feet per unit of common open space shall be provided.
(b) Up to 50 percent of the common open space requirement may be provided in an area constrained from development such as a critical area buffer, steep slope, or forested area; provided, that its use by residents respects the environmental constraints and regulations.
(c) Common space should be in one contiguous area, or no more than two separate areas.
(d) Each area should have a minimum dimension of 20 feet on all sides.
(e) The primary entry and porches of the cottages shall be oriented toward the common open space whenever feasible (with the exception of units adjacent to the public right-of-way which should have an entry on the right-of-way).
(2) Private Open Space.
(a) A minimum of 250 square feet of usable private open space shall be provided adjacent to each unit.
(b) Side setbacks shall not apply to the calculation of this private open space.
(c) Front or back yards, porches or decks, or additional side yard beyond the five-foot setback may be included in the calculation of private open space. (Ord. 10-09 § 1 (Exh. A))
18.37.110 Landscaping and vegetation.
(1) The provisions of the Covington tree preservation ordinance (Chapter 18.45 CMC) for commercial development shall apply. Native and drought-resistant vegetation is preferred.
(2) Cottage developments shall be designed around significant trees. Where feasible, existing mature trees which do not pose a safety hazard should be retained.
(3) Areas within a critical area or critical area buffer or within the shoreline management area shall abide by vegetation regulations for those areas.
(4) Landscaping located in common open space areas shall be designed to allow for easy access and use of the space by all residents, and to facilitate maintenance needs. (Ord. 10-09 § 1 (Exh. A))
18.37.120 Other design requirements.
Cottage housing units shall contain a variety of designs that include articulation of facades; changes in materials, texture, color, and window treatments; and other architectural features so all units do not appear identical. (Ord. 10-09 § 1 (Exh. A))
18.37.130 Ownership options.
Ownership may be fee simple lots with a homeowner’s association holding common areas, or condominium ownership of the whole development. (Ord. 10-09 § 1 (Exh. A))