Residential Height Allowances

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Calculation of proposed height for residential structures within the R-1 and R-2 Districts can be calculated using one of two methodologies, depending on whether or not the site is located within a View Sensitive District overlay (VSD).

Sites Located Outside the VSD
Building height for residential structures within the R-1 and R-2 outside of the VSD is calculated per the International Residential Code (IRC), which defines height as “the vertical distance from grade plane to the average height of the highest roof surface.”

Grade Plane is defined as “A reference plane representing the average of the finished ground level adjoining the building at all exterior walls. Where the finished ground level slopes away from the exterior walls, the reference plane shall be established by the lowest points within the area between the building and the lot line or, where the lot line is more than 6 feet (1829 mm) from the building between the structure and a point 6 feet (1829 mm) from the building.”

The height limit for main structures within the R-1 and R-2 Districts (outside of the VSD) is 35 feet and the height limit for accessory structures is 15 feet. For buildings with pitched roofs, that height is measured to the midpoint of the roof, as shown above.

Sites Located Within the VSD
Building height for residential structures within the R-1 VSD and R-2 VSD is calculated per the Tacoma Municipacl Code, which is measured to the peak or ridge of the building (not average height or midpoint). The height limit within the VSD is the vertical distance between existing grade and a plane essentially parallel to the existing grade.
The corners of such plane shall be located above the base points (not a point 6 feet out from the building).

Additional Height on Sloping VSD Sites
One foot of additional height is allowed on the lower corners of a building for every six percent of slope on sites located within the VSD.

Survey Requirements
As part of the plan review process, the City typically requires an initial survey of the property for sites within the VSD. If the proposed structure is not within the VSD, but is proposed to be within 5 feet of the allowed height, a survey may also be required. The survey is required to show the property corner elevations prior to any grading or development activity, the four foundation base points, and the proposed finished floor elevation.

The City may require a second survey at the time of the framing inspection.

  • The height survey is at the cost of the applicant.
  • Surveys must be signed and stamped by a surveyor licensed in the state of Washington.
  • The Building Official may waive some or all survey requirements if a detailed review of the site conditions indicates setback and height requirements are in compliance. The applicant may be required to submit plans, photos, and other documentation for this review.

Site Plan to Establish Height
Necessary elevation points on the site plan:

  • A fixed benchmark needs to be established on or near the site unless elevation above sea level is used
  • Four base elevation points (A-D)
    • Located at the four corners of the foundation, or if the foundation does not form a rectangle, at the smallest rectangle that surrounds the foundation.
    • Decks and/or porches that extend beyond the foundation are not included in the height calculation for additional slope on sites within the VSD.
    • If the site is not within the VSD and the ground level slopes away from the exterior walls, the reference plane shall be established by the lowest elevation points within the area between the building and the lot line or, where the lot line is more than 6 feet (1829 mm) from the building between the structure and a point 6 feet (1829 mm) from the building.
  • Finished Floor Elevation of the Structure

Elevation Drawings to Establish Height
Elevation drawings should include:

  • Grade Plane (non-VSD) or Existing Grade (VSD)
  • Height Limit Plane (VSD)
  • Actual Height of Structure (VSD and non-VSD)
  • Average Height of Highest Ridge (non-VSD)

Structures Allowed Above the Height Limits
The following are allowed above the height limit without approval of a height variance, per TMC 13.06.010.E-F:

  • Chimneys, steeples, flagpoles, elevators, fire or parapet walls, open railings, and other similar building appurtenances, provided that no useable floor space is added and all structural or other requirements are met.
  • Solar panels/collectors that do not extend more than 12-inches above the surface of the roof
  • Structures that are allowed to exceed the height limit through a Conditional Use Permit (CUP), per Tacoma Municipal Code 13.05.010.A. Tip Sheet L-640 explains the CUP process.
  • Schools, libraries, structures for religious assembly, and colleges in zoning districts with a height limit of 35 feet. These structures are allowed to extend up to 45 feet.
  • Shipping cranes and other freight moving equipment

Height Variances for Accessory Buildings
A height variance for an accessory building (not to exceed 25 feet) is only allowed in the following instances:

  1. Additional height is needed for building door clearance for the storage of a recreational vehicle or boat.
  2. Steep topography affects the site, which makes building a detached garage for personal vehicles difficult.
  3. When the rear yard of a site abuts an alley and the slope in the rear yard next to the alley is too steep to build an accessory building on, the height of the accessory building is measured from the grade of the alley to the highest point of the roofline of the accessory building with the approval of a height variance, which may include specific conditions.
  4. The additional height is needed to provide architectural compatibility between the accessory building and the main building, for features such as roof pitch and style.

All of the following facts and circumstances must exist for approval of a height variance for an accessory building:

  1. Additional height shall be the minimum necessary to afford relief.
  2. The variance is in the interest of the general public.
  3. The variance is in the general interest of the particular neighborhood.
  4. For purposes of this variance, the interest of the general public and the general interest of the particular neighborhood are indicated, in part, by the Comprehensive Plan.

Height Variances Within the VSD – Criteria
Requests for a height variance in the VSD are generally based on the following:

  1. the extent of the view and the character of the area;
  2. the impact of the proposed construction on the view from adjacent properties;
  3. the effect of any possible restrictions on the proposed construction, the character of the area;
  4. the topography of the site and surrounding properties;
  5. the variance is in the interest of the general public; and
  6. the variance is in the general interest of the particular neighborhood.

Mitigation – The following factors may make approval of a height variance more appropriate:

  1. orientation of the ridgeline to minimize view impairment;
  2. style of roof;
  3. increased setback from the street or the side lot line; and
  4. the placement of the structure(s) on the site.

Height Variances Outside the VSD 
Requests for a height variances within the R-1 and R-2 Districts, located outside of the VSD, are held to the same criteria as a variance to required setbacks/lot size. See Tip Sheet L-645.

Applicable Regulations

 

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