§ 113.5. Construction Limitations.  


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  • No building or structure shall be constructed over or upon the trace of a known active earthquake fault which is shown on maps maintained by the Building Official. These maps include, but are not limited to, earthquake fault zone maps prepared under Sections 2622 and 2623 of the California Public Resources Code.

    The absence of a known active earthquake fault trace at the proposed building location shall be determined by a professional geologist licensed in the State of California in the following cases:

    1.

    When the proposed building is within (50) feet (15.24 m) of that line designated by the Building Official as the assumed location of a known active earthquake fault on the aforementioned maps.

    2.

    When the proposed building is within 50 feet (15.24 m) of the most probable ground location of the trace of a known active earthquake fault shown on the aforementioned maps.

    In these cases the Building Official may require the excavation of a trench, for the purpose of determining the existence of an active earthquake fault. Such a trench will be required if a lack of distinguishable fault features in the vicinity prevents the Building Official from determining by a site examination, review of available aerial photographs, or by other means that the fault trace does not underlie the proposed building. The trench shall be approximately perpendicular to the most probable direction of the fault trace, at least 1-1/2 feet (0.15 m) wide, and at least five feet in depth measured from natural grade, or to a depth satisfactory to the Building Official.

    The trench must be accessible for mapping and inspection by the Building Official, when requested, and meet the requirements of Title 8 of the California Code of Regulations, Construction Safety Orders. The trench need not extend further than the full width of the proposed structure plus 5 feet (1.52 m) beyond the traversed exterior walls. A known active earthquake fault shall be presumed nonexistent if an exposure is not found by the professional geologist in the walls or floor of the trench.

    The Building Official may require a more extensive investigation by a professional geologist as evidence to the absence of a known active earthquake fault prior to the issuance of a permit for Groups A, E, I, H and R, Division 1 Occupancies and B, F, M and S Occupancies over one story in height.

    The results of the investigation, conclusions and recommendations shall be presented in a geology report prepared by a professional geologist as defined by Section 113.3. The report shall comply with the guidelines presented in Note 49 prepared by the California Department of Conservation, Geological Survey.

    The Building Official may waive the requirements for an active earthquake fault investigation for additions to existing one- or two-family dwelling units when all of the following conditions are met:

    1.

    There is no increase in the number of bedrooms or bedroom equivalent rooms in the dwelling unit;

    2.

    The addition does not increase the permitted gross floor area of the structure by more than 20 percent as it existed on January 1, 2017, or 400 square feet, whichever is less;

    3.

    The Building Official has determined that the addition is not located over or upon the trace of a known active earthquake fault as shown on the aforementioned maps; and

    4.

    The owner shall record in the office of the Department of Registrar-Recorder a statement acknowledging that the owner is aware that the records of the Building Official indicate that the property is potentially subject to a hazard from a known active earthquake fault. The owner shall also record in the office of the Department of Registrar-Recorder an agreement relieving the County and all officers and employees thereof of any liability for any damage or loss which may result from the issuance of such a permit. This agreement shall provide that it is binding on all successors in interest of the owner and shall continue in effect until the Building Official records in the office of the Department of Registrar-Recorder a statement that the Building Official has determined that a hazard from a known active earthquake fault no longer exists.

    EXCEPTION: The provisions of this Section do not apply to:

    1.

    One-story, detached light-frame buildings not intended or used for human occupancy and not exceeding 1,000 square feet (92.9 m ) in gross floor area or 12 feet (3.66 m) in building height.

    2.

    Alterations or repairs to an existing building provided that the aggregate value of such work within any 12-month period does not exceed 50 percent of the current market value of the existing building. For the purposes of this Section 113.5, "alteration" does not include an addition or additions.

    3.

    Swimming pools, retaining walls, fences and minor work of a similar nature.

(Ord. 2016-0053 § 2, 2016; Ord. 2013-0048 § 2, 2013; Ord. 2007-0108 § 2 (part), 2007; Ord. 2002-0076 § 55, 2002: Ord. 95-0065 § 3 (part), 1995.)