Chapter 18.40
HEIGHT, YARDS, AREA, AND OPEN SPACES – GENERAL PROVISIONS

Sections

18.40.010    Regulations subject to chapter.

18.40.020    Height of buildings on through lots.

18.40.030    Height of structures and roof structures.

18.40.035    Construction on artificial grades.

18.40.040    Yards and open spaces.

18.40.050    Greater yard and open space requirements include minimum requirements.

18.40.060    Modification or adjustment of side yard requirements on consolidated lots or oversize building sites.

18.40.070    Yard requirements when more than one main building exists.

18.40.080    Method for determining modification of required front yard on steep lots.

18.40.090    Modification of required front yards where nonconformities exist.

18.40.100    Yard requirements for property abutting half-streets or streets designated by official control.

18.40.110    Measurement of front yards.

18.40.120    Vision clearance – Corner and reverse corner lots.

18.40.130    Permitted intrusions into required yards.

18.40.140    Location of swimming pools.

18.40.150    Location of wall, fence, or hedge.

18.40.160    Required increase of side yard where multiple or row dwellings front upon a side yard.

18.40.170    Required increase of side yard where multiple or row dwellings rear upon a side yard.

18.40.180    Yard requirements on through lots.

18.40.190    Lot area not to be reduced.

18.40.200    Dividing an improved building site area prohibited.

18.40.210    Greater yards and open spaces not to be alienated.

18.40.220    Greater lot area may be required.

18.40.230    Substandard or nonconforming lots in single-family residential zones.

18.40.240    Substandard lots may be combined.

18.40.250    Use of lots or parcels containing more than minimum required lot area.

18.40.260    Dangerous fences – Restrictions.

18.40.010 Regulations subject to chapter.

The foregoing regulations of this title shall be subject to the general provisions, conditions, and exceptions contained in this chapter. [Ord. 175 § 1(24.48.010), 1964.]

18.40.020 Height of buildings on through lots.

On through lots divided by a zone boundary line, the line shall be considered a property boundary line for purposes of determining the permitted height on the building site. [Ord. 175 § 1(24.48.020), 1964.]

18.40.030 Height of structures and roof structures.

Penthouses or roof structures for the housing of elevators, stairways, tanks, ventilating fans, or similar equipment required to operate and maintain the building; fire or parapet walls, skylights, flagpoles, chimneys, smokestacks, church steeples and belfries, utility line towers and poles, and similar structures may be erected above the height limits of this title; provided, however, no penthouse or roof structure, or any other space above the height limit prescribed for the zone in which the building or structure is located shall be allowed for the purpose of providing additional floor space. [Ord. 445 § 6, 1978: Ord. 175 § 1(24.48.030), 1964.]

18.40.035 Construction on artificial grades.

The height of any structure constructed on an artificial grade shall be measured from existing grade, as defined in DMMC 14.60.030, in accordance with the formula contained in DMMC 18.04.320. The decision as to whether a grade is artificial shall be made by the building department, subject to appeal to the hearing examiner in accordance with the hearing examiner code, and shall be based on the intent of the developer as professionally perceived by the building department. No grade shall be deemed artificial if, in the professional opinion of the building department, the change of grade is necessary for development of the property on the basis of sound engineering principles and customary construction practices in the area. [Ord. 801 § 2, 1989: Ord. 564 § 2, 1983.]

18.40.040 Yards and open spaces.

Except as may be otherwise provided in this title, every required yard and open space shall be open and unobstructed from the ground to the sky. No yard or open space provided around any building for the purpose of complying with the provisions of this title shall be considered as providing a yard or open space for any other building, and no yard or open space on any lot or parcel shall be considered as providing a yard or open space on an adjoining lot or parcel whereon a building is to be erected. [Ord. 175 § 1(24.48.040), 1964.]

18.40.050 Greater yard and open space requirements include minimum requirements.

Wherever in this title a particular use, or a building in connection with a particular use, is specifically required to maintain a distance from any boundary property line or other building or buildings on the site greater than the minimum standard required yard or open space set forth for the zone, such greater distance is intended to apply only to the particular building, buildings, or use involved and the standard required minimum yards and open spaces required for the zone (if any) shall be included as a part of the greater required distance or open space for the specified building, buildings, or use. [Ord. 175 § 1(24.48.050), 1964.]

18.40.060 Modification or adjustment of side yard requirements on consolidated lots or oversize building sites.

When the common property line separating two contiguous lots is covered by a building or permitted group of buildings, such lots shall constitute a single building site and the yard spaces required by this title shall then not apply to such common property line. [Ord. 175 § 1(24.48.060), 1964.]

18.40.070 Yard requirements when more than one main building exists.

Where two or more buildings are, by definition of this title, considered to be main buildings, then the front yard requirements shall apply only to the building closest to the lot front line. [Ord. 175 § 1(24.48.070), 1964.]

18.40.080 Method for determining modification of required front yard on steep lots.

On any lot where the natural gradient or slopes, as measured from the lot front line along the centerline for the lot for a distance of 60 feet is in excess of 35 percent, then the required front yard may be reduced one foot for each one percent of gradient or slope in excess of 35 percent. [Ord. 175 § 1(24.48.020), 1964.]

18.40.090 Modification of required front yards where nonconformities exist.

(1) The depth of required front yards on unimproved lots may be modified when any of the following circumstances apply:

(a) When the unimproved lot or lots are located between lots having nonconforming front yards;

(b) When the unimproved lot or lots are located between a lot having a nonconforming front yard and a lot having a conforming front yard;

(c) When the unimproved lot or lots are located between a lot having a nonconforming front yard and a vacant corner lot; and

(d) Where a vacant corner lot or reverse corner lot adjoins a lot having a nonconforming front yard.

(2) A nonconforming front yard shall be deemed to be an area between the lot front line and the portion of the main building closest to it, which area is less in depth than that defined by this title as constituting a required front yard. On a lot having a nonconforming front yard the degree of nonconformity to be credited in making the adjustment shall in no instance exceed 60 percent of the front yard depth required on the nonconforming lot, such percentage to be measured from the rear line of the required front yard on such lot toward the lot front line.

(3) The rear line of the modified front yard on the unimproved lot or lots as referred to in subsection (2) of this section shall be established in the following manner:

(a) On lots having nonconforming front yards a point shall be established at the intersection of the line determining the depth of the lot with a line coincident with the front of the building causing the nonconforming conditions;

(b) On lots having conforming front yards or on a vacant corner lot, a point shall be established at the intersection of the line determining the depth of the lot with the rear line of the required front yard;

(c) A straight line shall be drawn from such point of intersection on the lot with the nonconforming front yard across any intervening unimproved lot or lots to a point established on the next lot in either direction as set forth in paragraphs (a) and (b) above; and

(d) The depth of the modified front yard on any lot traversed by the straight line defined in paragraph (c) of this subsection shall be established by the point where the straight line intersects the line constituting the depth of each such intervening lot.

(4) When an unimproved corner lot or reverse corner lot adjoins a lot having a nonconforming front yard, the front yard on the corner lot or reverse corner lot may be the same as that on the adjoining lot; provided, the placement of the buildings does not interfere with the required vision clearance at the corner formed by the intersection of the streets. [Ord. 175 § 1(24.48.090), 1964.]

18.40.100 Yard requirements for property abutting half-streets or streets designated by official control.

(1) A building or structure shall not be erected on a lot which abuts a street having only a portion of its required width dedicated and where no part of such dedication would normally revert to the lot if the street were vacated, unless the yards provided and maintained in connection with such building or structure have a width or depth of that portion of the lot needed to complete the road width plus the width or depth of the yards required on the lot by this title, if any. This section applies to all zones.

(2) Where an official control adopted pursuant to law includes plans for the widening of existing streets, the connecting of existing streets, or the establishment of new streets, the placement of buildings and the maintenance of yards, where required by this title, shall be measured from the future street boundaries as determined by such official control. [Ord. 175 § 1(24.48.100), 1964.]

18.40.110 Measurement of front yards.

Front yard requirements shall be measured from the property front line or the indicated edge of a street for which an official control exists, except as provided in DMMC 18.40.100. [Ord. 175 § 1(24.48.110), 1964.]

18.40.120 Vision clearance – Corner and reverse corner lots.

All corner lots and reverse corner lots subject to yard requirements shall maintain for safety vision purposes a triangular area, one angle of which shall be formed by the lot front line and the side line separating the lot from the street, and the sides of the triangle forming the corner angle shall each be 15 feet in length measured from the aforementioned angle. The third side of the triangle shall be a straight line connecting the last two mentioned points which are distant 15 feet from the intersection of the lot front and side lines. Within the area comprising the triangle no tree, fence, shrub, or other physical obstruction higher than 42 inches above the established grade shall be permitted. [Ord. 175 § 1(24.48.120), 1964.]

18.40.130 Permitted intrusions into required yards.

The following may project into required yards:

(1) Fireplace structures not wider than eight feet measured in the general direction of the wall of which it is a part – 18 inches into any yard;

(2) Uncovered porches and platforms which do not extend above the floor level of the first floor – 18 inches into side yards and six feet into the front yard; provided, they may extend three feet into the side yard when they do not exceed 18 inches in height above the finished grade; and

(3) Planting boxes or masonry planters not exceeding 42 inches in height in any required front yard. [Ord. 175 § 1(24.48.130), 1964.]

18.40.140 Location of swimming pools.

In any zone, a swimming pool may not be located in any required front yard, nor closer than five feet to any property line or to any building on the same premises. [Ord. 175 § 1(24.48.140), 1964.]

18.40.150 Location of wall, fence, or hedge.

In any residential zone a wall, fence, or hedge is permitted under the following conditions:

(1) Where a fence of hedge is located directly on the ground, the height of the fence shall be the vertical distance from the top board, rail, or wire to the ground directly below the fence; where a masonry wall is used as a fence, the height shall be the vertical distance from the top surface of the wall to the ground on the high side of the wall;

(2) In any zone a wall, fence, or hedge not more than 42 inches in height may be located and maintained on any part of a lot;

(3) On interior lots a wall, fence, or hedge not exceeding six feet in height may be located on any lot line to the rear of the rear line of the required front yard; provided, where a lot rears upon an alley any such wall, fence, or hedge along the lot rear line shall contain a gate affording access to the alley;

(4) On corner lots a fence, wall, or hedge not exceeding six feet in height may be located on the lot interior side line to the rear of the rear line of the required front yard, and on the lot rear line except that along the portion of the lot rear line constituting the width of the required side yard on the side street side, the wall, fence, or hedge shall not exceed a height of 42 inches; on the side street side of a corner lot a wall, fence, or hedge exceeding 42 inches in height shall observe the required side yard;

(5) On reverse corner lots a wall, fence, or hedge not exceeding six feet in height may be located on the lot interior side line to the rear of the rear line of the required front yard; if the lot rears upon an alley, a wall, fence, or hedge not exceeding six feet in height may be located on the lot rear line except that along the portion of the lot rear line constituting the width of the required side yard on the side street side, such wall, fence, or hedge shall not exceed a height of 42 inches; on the side street side, a wall, fence, or hedge exceeding 42 inches in height shall observe the required side yard;

(6) Where a retaining wall protecting a cut below the natural grade is located on the line separating lots or parcels, such retaining wall may be topped by a fence, wall, or hedge of the same height that would otherwise be permitted at the location if no retaining wall existed, and the top of the retaining wall shall be considered the bottom of the fence;

(7) Where a retaining wall contains a fill, the height of the retaining wall built to retain the fill shall be considered as contributing to the permissible height of a wall, fence, or hedge, and shall be measured from the ground on the low side; provided, that in any event a protective fence not more than 42 inches in height may be erected at the top of the retaining wall and any portion of such fence above the six-foot maximum height shall be an open-work fence; an open-work fence means a fence in which the component solid portions are evenly distributed and constitute not more than 50 percent of the total surface area of the face of the fence;

(8) Electric fences shall not be permitted in any residential zone;

(9) No fence shall be located in any public right-of-way;

(10) Any fence exceeding a height of six feet, and any retaining wall exceeding a height of 48 inches shall require a building permit; the provisions and conditions of this section shall not apply to fences required by state law to surround and enclose public utility installations, or to chain link fences enclosing school grounds and public playgrounds. [Ord. 1237 § 4, 1999; Ord. 175 § 1(24.48.150), 1964.]

18.40.160 Required increase of side yard where multiple or row dwellings front upon a side yard.

The minimum width of the side yard upon which multiple or row dwellings front shall be not less than 10 feet. Open, unenclosed porches not extending above the floor level of the first floor may project a distance of not more than three feet into the side yard upon which such dwellings front. [Ord. 175 § 1(24.48.160), 1964.]

18.40.170 Required increase of side yard where multiple or row dwellings rear upon a side yard.

Where multiple or row dwellings are arranged so that the rear of such dwellings abuts upon a side yard, and such dwellings have openings onto such side yard used as secondary means of access to such dwellings, the required side yard to the rear of such dwellings shall be increased by one foot for each opening onto such side yard. [Ord. 175 § 1(24.48.170), 1964.]

18.40.180 Yard requirements on through lots.

(1) If a through lot is improved as one building site, the main building shall conform to the requirements of the zone of the frontage occupied by such main building, and in residential zones no accessory building shall be located closer to either street than the distance constituting the required front yard on such street, and required side yards shall extend the full depth of the lot.

(2) If a through lot is divided by a zone boundary line, the line shall be considered a property boundary line for purposes of determining the required yards and open spaces. [Ord. 1237 § 4, 1999; Ord. 175 § 1(24.48.180), 1964.]

18.40.190 Lot area not to be reduced.

The lot area of any lot recorded prior to August 3, 1964, shall not be so reduced or diminished that the area, width, yards, or other open spaces shall be less than prescribed by this title for the zone in which the property is located, nor shall the number of dwelling units be increased in any manner except in conformity with the regulations established by this title. In multiple lot subdivisions recorded subsequent to August 3, 1964, the minimum lot area requirement for each lot in the subdivision shall be deemed to have been conformed to if the average lot areas for all lots in the subdivision meet the minimum requirements set forth in the zone applying to the property. [Ord. 1237 § 3, 1999; Ord. 175 § 1(24.48.190), 1964.]

18.40.200 Dividing an improved building site area prohibited.

When a single lot or parcel contains twice the minimum required lot area or more for the zone in which it is located, and the total area of the site has been used to compute the number of dwelling units to be located thereon, the building or buildings which contain dwelling units shall be so located on the property as to cover, at least in part, any line that would represent a property line between two or more parcels that could result from an otherwise legal division of the original lot or parcel, and thereafter no property shall be alienated from the building site which would reduce the total required area of the site upon which the number of dwelling units located thereon was based. [Ord. 175 § 1(24.48.200), 1964.]

18.40.210 Greater yards and open spaces not to be alienated.

Where a greater height of buildings has been accomplished by reason of providing increased yards or open spaces, no property may be alienated from the lot or building site which would reduce the yards or open spaces provided to compensate for the greater height of the building, nor which would reduce the total required minimum area of the site upon which area the permitted floor space contained in such building was based. [Ord. 175 § 1(24.48.210), 1964.]

18.40.220 Greater lot area may be required.

Greater lot areas than those prescribed in the various zones may be required when such greater areas are established by the adoption of a planned unit development as provided in this title. [Ord. 175 § 1(24.48.220), 1964.]

18.40.230 Substandard or nonconforming lots in single-family residential zones.

In any single-family residential zone, a single-family dwelling may be established on a lot which cannot satisfy the lot area requirements of the zone; provided: (1) that all other bulk regulations shall apply, and (2) that the owner of such nonconforming lot does not own any adjoining vacant lots of record of continuous boundary to which the nonconforming or substandard lot can be merged in title or with which the lot lines can be adjusted to create lots of record which satisfy the lot area requirements of the zone or create a lot of record of greater area, and (3) that the owner of such nonconforming lot or lots has not received a fee interest in such lot or lots from a party who at any time subsequent to April 25, 1988 held a fee interest in any adjoining lot of continuous boundary; and further provided, that limitation (3) above shall not apply to a party who either (A) acquires a fee interest by enforcement of a security interest in such property where the security interest was created prior to April 25, 1988, or (B) has acquired such fee interest as the result of a judicial decree of partition by a court of competent jurisdiction. [Ord. 756 § 1, 1988.]

18.40.240 Substandard lots may be combined.

In an RA or multifamily residential zone two or more substandard lots or fractions of lots, or a standard lot and substandard lot or fraction of lots may be consolidated into a single building site; provided, the total area of such consolidated lots is less than twice the required minimum lot area of the zone in which the property is located. In an RA or multifamily residential zone a single building, which complies with the requirements of the zone in which it is located, may be erected on such consolidated site containing as many dwelling units as would be permitted if each substandard lot or fraction of a lot were improved individually. No portion of the consolidated building site shall thereafter be alienated which would reduce the area upon which the number of dwelling units allowed thereon was based. [Ord. 1237 § 4, 1999; Ord. 1197 § 29, 1997; Ord. 231 § 1, 1968: Ord. 175 § 1(24.48.240), 1964.]

18.40.250 Use of lots or parcels containing more than minimum required lot area.

When a lot contains two or more times the minimum lot area required for the zone in which the lot is located, and the owner desires to use each unit of area equivalent to the minimum lot area as a separate building site; provided, not more than four such units result, and no dedication of streets, alleys, or other public ways are involved, such area units may be so utilized only after approval of the lot division as prescribed in the subdivision code (Title 17 DMMC). When such units are thus defined, then all of the provisions of this title governing the use of a lot in the zone in which such property is located shall apply thereto. [Ord. 175 § 1(24.48.250), 1964.]

18.40.260 Dangerous fences – Restrictions.

Dangerous fences are subject to the following restrictions:

(1) Fences containing razor wire, coiled barbed wire, or material(s) of similar design are prohibited in all residential zones, except that the community development director may approve such dangerous fences in residential zones for jails, detention facilities and other methods of court-ordered personal confinement, through the building permit process. Only those fences to be used for the purposes set forth in this subsection will be allowed under such permit.

(2) Electric fences are not permitted in the city except when used to contain grazing animals in an area zoned to allow such a use. Electric fences must be set back at least five feet from the property line or must be enclosed by additional fencing or other barriers which prevent access to the electric fence by small children on the adjacent property.

(3) A barbed wire fence may be a maximum of five feet in height and may contain four strands of taut parallel barbed wire.

(4) A fence or wall may incorporate a maximum of three strands of parallel barbed wire a maximum of two feet in height on top of the fence, so long as the orientation is either straight up or angled in toward the site. If such a fence contains three strands of barbed wire which are oriented outward from the site, the fence shall be set back from the property line a distance of one to 10 feet as determined by the community development director, based on the following criteria:

(a) The proximity of the fence to existing or planned sidewalks, pedestrian ways, or public parking areas;

(b) Whether the security needs for the property can be satisfied;

(c) Whether the location of the fence will degrade the aesthetics of the surrounding area;

(d) Whether the fence location is in the best interest of the health, safety and welfare of the general public;

(e) Whether either required landscaping can be fulfilled, or landscaping is otherwise provided to ameliorate visual impacts of the fence;

(f) The proximity of the fence to environmentally critical areas, open space, or other such areas likely to provide habitat for urban mammals.

(5) In residential zones, all permitted dangerous fences shall comply with height and setback restrictions for all fences as set forth in DMMC 18.40.150. For properties where both codes apply, the more restrictive code shall prevail.

(6) All fences not in compliance with this section shall, within 60 days of notification from the city, be removed by the owner or, upon failure to remove the fence, the community development director is empowered to cause the removal of the fence, the cost of which shall be billed to the owner. [Ord. 1315 § 2, 2003.]