Density and Height Bonuses

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The Tacoma Municipal Code includes density and height bonuses for incorporating sustainable features into building and site design.

DENSITY BONUS FOR PLANNED RESIDENTIAL DEVELOPMENT (PRD) DISTRICT
The PRD is to be located in areas already providing amenities and services for residential dwelling districts, and in locations not adversely affecting adjacent properties.

Built Green 4 Stars or LEED Gold for Building Design and Construction is required. (TMC 13.06.140)

Additional density may be permitted as follows:

  • An additional 0.50 times the underlying district density is permitted through the provision of affordable housing units, pursuant to TMC 1.39. Once this is achieved,
  • An additional 0.25 times the underlying district density is permitted for either achieving Built Green Emerald Star or Living Building Challenge 3 Petals and, if new roadway sections are constructed, Greenroads Gold.

DOWNTOWN– DESIGN STANDARDS FOR INCREASING ALLOWABLE FLOOR AREA RATIO (FAR)
The Development Standards Table in the Tacoma Municipal Code (13.06.A.060) includes allowed FAR for downtown district buildings. Building FAR may be increased (allowing for a larger building footprint) when select design standards listed in the Tacoma Municipal Code 13.06.A.080, Design Standards for Increasing FAR are incorporated.

For each of the following incorporated design standards, the allowable FAR can be increased by 0.5 times (up to the maximum FAR listed in the Development Standards Table):

  • Exterior public space equivalent to at least five percent of the site area with options including trees and other plantings; and solar exposure during the summer;
  • Landscaping covering at least 15 percent of the surface of the roof and/or the use of vegetated roofs;
  • Retention and renovation of any designated or listed historic structure(s) located on the site.

MIXED-USE DISTRICTS HEIGHT BONUSES
The Height Bonus program (TMC 13.06.300.E.2) provides a mechanism to allow for additional height for projects within certain portions of the Mixed-Use Centers, with the intent of encouraging new growth and fostering economic vitality within the centers. Eligible projects increase the standard maximum height limit through the incorporation of one or more public-benefit features, up to the maximum allowed height.

Bonus features (with the exception of vegetated roofs which can be counted for stormwater management and energy efficiency bonuses) cannot be counted more than once toward the additional allowed height or be worth more than the maximum height identified for that feature, even if the project provides more than the minimum amount required to qualify. Providing a bonus feature twice or at double the level described is not worth twice the bonus amount.

  1. STORMWATER MANAGEMENT

A height bonus of 10 feet may be granted for integrated systems that use low impact development (LID) techniques such as permeable surfaces, roof rainwater collection systems and bioretention/rain gardens, etc. The system shall be designed to result in:

  • No net increase in the rate and quantity of stormwater runoff from existing to developed conditions; or
  • If the amount of imperviousness is greater than 50%, the system shall be designed to result in a 25% decrease in the rate and quantity of runoff.
  1. VEGETATED ROOFS

A height bonus of 10 feet may be granted for vegetated roofs which cover at least 60% of the building footprint. Roofs shall:

  • Conform to best available technology standards, such as those published by Leadership in Energy and Environmental Design (LEED);
  • Be designed in accordance with the City of Tacoma Stormwater Management Manual.
  1. SOLAR ENERGY COLLECTION

A height bonus of 10 feet may be granted for solar energy system installation that provides at least 15% of a building’s expected annual operating energy. In addition, solar panels/collectors are allowed to exceed maximum height limit as long as they do not extend more than 12 inches above the surface of the roof (TMC 13.06.602).

The system shall be designed and installed under the direction of a professional with demonstrated expertise in the design and construction of such systems.

  1. ENERGY EFFICIENCY

A height bonus of 10 feet may be granted for energy reduction beyond prerequisite standards by at least 20% for new structures and 10% for existing structures or existing portions of structures. Projects shall use an energy cost budget analysis to demonstrate energy savings over current standards.

Maximum allowable roof height may be increased by eight inches when adding insulation to the exterior of the existing building structural frame (not applicable within view-sensitive districts) (TMC 13.06.602).

  1. HISTORIC PRESERVATION

A height bonus of 10 feet may be granted for:

  • Adjacent historic rehabilitation: retention, substantial renovation and incorporation of a designated or listed city landmark adjacent to new construction.
  • Landmark designation: voluntary placement of any significant historic building in the same Mixed-Use Center on the Tacoma Register of Historic Places.
  • Historic façade retention: retention and incorporation of an existing façade that is 50 or more years in age.

MIXED USE DISTRICT HEIGHT BONUS FOR TRANSIT-ORIENTED DEVELOPMENT

  • A height bonus of five feet may be granted for projects that include transit stop/station improvements of twice the level of improvements that are required by code (TMC 13.06.511)
  • A height bonus of 10 feet may be granted if at least 50% of the floor area is for residential use.

MIXED USE DISTRICT HEIGHT BONUS FOR PEDESTRIAN-ORIENTED ENVIRONMENT
A height bonus of 10 feet may be granted for projects that include at least 50% of the required parking within the building footprint (above or below ground).

A height bonus of 20 feet may be granted for projects with all parking provided within the building footprint (above or below ground).

DETACHED ACCESSORY DWELLING UNIT (DADU) HEIGHT BONUS
The maximum height for detached ADUs shall be 18 feet, measured per the Building Code, or up to 20 feet with incorporation of either parking on the main level of the structure, or with certification of the DADU under Built Green 4 stars criteria, or equivalent environmental certification.

RESOURCES

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