18.12.050   Permitted Encroachments, Projections and Exceptions
   The following projections and encroachments into required yards, daylight plane and height are permitted, provided a projection shall not be permitted to encroach into a special setback, as established by the setback map pursuant to Chapter 20.08 of the Palo Alto Municipal Code, except as noted in subsection (a)(1)(D) below.
   (a)   Setback/Yard Encroachments and Projections
      (1)   Horizontal Additions
   Where a single-family dwelling legally constructed according to existing yard and setback regulations at the time of construction encroaches upon present required yards, one encroaching side (first floor wall) of the existing structure, at a height not to exceed 12 feet, may be extended in accord with this section. Only one such extension shall be permitted for the life of such building. This subsection shall not be construed to allow the further extension of an encroachment by any building that is the result of the granting of a variance, either before or after such property became part of the city.
         (A)   Front Yard. In cases where the existing setback is less than 20 feet, but at least 14 feet, the existing encroachment may be extended for a distance of not more than 100% of the length of the encroaching wall to be extended; provided, that the total length of the existing encroaching wall and the additional wall shall together not exceed one-half the maximum existing width of such building.
         (B)   Interior Side Yard. In cases where the existing setback is less than 8 feet, but at least 5 feet, the existing encroachment may be extended for a distance of not more than 100% of the length of the encroaching wall to be extended but not to exceed 20 additional feet.
         (C)   Street Side Yard. In cases where the existing setback is less than 16 feet, but at least 10 feet, the existing encroachment may be extended for a distance of not more than 100% of the length of the encroaching wall to be extended, but not to exceed 20 feet.
         (D)   Special Setbacks. In cases where a special setback is prescribed pursuant to Chapter 20.08 of the Municipal Code, and the existing setback is less than the special setback distance, and at least 14 feet for the front setback or at least 10 feet for the street side yard setback, the exiting encroachment may be extended for a distance of not more than 100% of the length of the encroaching wall to be extended, provided that the total length of the existing encroaching wall and the additional wall shall together not exceed one-half the maximum existing width of such building.
      (2)   Rear Yard Encroachments for Portions of Homes
      A portion of a main building that is less than half the maximum width of the building may extend into the required rear yard no more than six feet and with a height of no more than one story, except that for a corner lot having a common rear property line with an adjoining corner lot, the building may extend into the required rear yard not more than ten feet with a height of no more than one story.
      (3)   Allowed Projections
         (A)   Cornices, Eaves, Fireplaces, and Similar Architectural Features
   For cornices, eaves, fireplaces, and similar architectural features, excluding flat or continuous walls or enclosures of usable interior space, the following projections are permitted:
            (i)   A maximum of two feet into a required side yard. Fireplaces in a required side yard may not exceed five feet in width. Fireplaces not exceeding five feet in width may project into a required side yard no more than two feet.
            (ii)   A maximum of four feet into a required front yard.
            (iii)   A maximum of four feet into a required rear yard.
         (B)   Window Surfaces
            (i)   Window surfaces, such as bay windows or greenhouse windows, may extend into a required rear yard a distance not to exceed two feet, into a required street side setback a distance not to exceed three feet, or into a required front yard a distance not to exceed three feet.
            (ii)   Window surfaces may not extend into required interior side yards, with the exception that one greenhouse window with a maximum width of six feet, framed into a wall, may project into the interior side yard no more than two feet. The window surface may not extend into any yard above a first story.
         (C)   Storage Structures
   Storage structures not over six feet in height or twenty-five square feet in floor area may be located in interior side yards and rear yards according to the provisions of Section 18.12.080(b) for accessory structures. Where the provisions of Section 18.12.080(b) for front and/or street side yard setbacks are not met, the following projections are permitted for such structures:
            (i)   A maximum of two feet into a required side yard.
            (ii)   A maximum of four feet into a required front yard.
            (iii)   A maximum of four feet into a required rear yard.
         (D)   Patios, Decks, Stairways, Landings, Balconies, or Fire Escapes
   For uncovered porches (less than 30 inches above grade), patios, decks, stairways, landings, balconies, or fire escapes the following projections are permitted, provided these projections are not permitted above the first story:
            (i)   A maximum of three feet into a required side yard.
            (ii)   A maximum of six feet into a required front yard.
            (iii)   A maximum of six feet into a required rear yard.
         (E)   Canopy or Patio Cover
   A canopy or patio cover may be located in the required rear yard or that portion of the interior side yard, which is more than 75 feet from the street lot line measured along the common lot line. Such canopies shall be subject to the following conditions:
            (i)   A canopy or patio cover shall not be more than 12 feet in height.
            (ii)   The canopy or patio cover shall be included in the computation of building coverage.
            (iii)   The canopy or patio cover and other structures shall not occupy more than fifty percent of the required rear yard.
            (iv)   The canopy or patio cover shall not be enclosed on more than two sides.
         (F)   Pools, Spas, and Hot Tubs
            (i)   Pools, spas, and hot tubs may extend into a required rear yard a distance not to exceed fourteen feet, provided that a minimum setback of six feet from the property line shall be maintained.
            (ii)   No swimming pool, hot tub, spa, or similar accessory facility shall be located in any portion of a required front or street side yard.
   (b)   Height and Daylight Plane Exceptions
      (1)   Height Exceptions
   Flues, chimneys, and antennas may exceed the established height limit by not more than 15 feet.
      (2)   Daylight Plane Exceptions
   The following features may extend beyond the daylight plane established by the applicable district, provided that such features do not exceed the height limit for the district unless permitted to do so by subsection (b)(1) above:
         (A)   Television and radio antennas;
         (B)   Chimneys and flues that do not exceed 5 feet in width, provided that chimneys do not extend past the required daylight plane a distance exceeding the minimum allowed pursuant to Chapter 16.04 of this code.
         (C)   Dormers, roof decks, gables, or similar architectural features, provided that:
            (i)   the sum of the horizontal lengths of all such features shall not exceed 15 feet on each side; and
            (ii)   the height of such features does not exceed 24 feet;
            (iii)   no single feature exceeds 7.5 feet in length; and
            (iv)   there is a minimum 5 foot separation between each feature.
         (D)   Cornices, eaves, and similar architectural features, excluding flat or continuous walls or enclosures of usable interior space, provided such features do not extend past the daylight plane more than 2 feet.
(Ord. 5373 § 9 (part), 2016; Ord. 4964 § 14, 2007: Ord. 4869 § 14 (Exh. A [part]), 2005)