HomeMy WebLinkAboutGrade & Structure HeightCITY OF NEWPORT BEACH
PLANNING COMMISSION STAFF REPORT
Agenda Item No. 3
February 5, 2004
TO: PLANNING COMMISSION
FROM: James Campbell, Senior Planner
(949) 644 -3210, icamabell Co�citv.newoort- beach.ca.us
SUBJECT: Grade and Structure Height
Introduction
Commissioner Eaton requested a report from staff on the definition of grade and
how the height of buildings and structures is measured.
Discussion
The Municipal Code establishes how the height of structure is determined.
Specifically, Section 20.65.030.A states:
Weight of Structure. The height of a structure shall be the vertical distance between
the highest point of the structure and the grade directly below. In determining the
height of a sloped roof, the measurement shall be the vertical distance between the
grade and the midpoint of the roof plane, as measured from the ridge of the roof to
where the wall plate intersects the roof plane, provided that no part of the roof shall
extend more than 5 feet above the permitted height in the height limitation zone."
Grade is defined as the unaltered vertical location of the ground surface unless it
is altered or some other grade is identified. Section 20.65.030.13 states:
"Grade. For the purpose of measuring height the grade shall be the unaltered
natural vertical location of the ground surface unless one of the following applies:
At the time of subdivision, the City has approved a grading plan or map,
under which circumstances grade shall be finished grade as shown on the
plan or map so approved. For sites that were developed without or prior to
the requirement for a grading plan or map, the Planning Department shall
exercise its best efforts to determine the location of grade for the purpose of
measuring height. In so doing, the Planning Department shalt use existing
on -site elevations and contours, as well as the elevations and contours of
adjoining and nearby properties to determine the natural profile of the site. In
cases where retaining walls have been constructed or filled surfaces have
been used for the purpose of measuring height prior to October 12, 1972, the
finished grade established in conjunction with the filled condition shall be
used for the measurement of height. Under no circumstances shall height be
measured from excavated surfaces such as basements and wine cellars
which have been used to artificially lower the ground surface.
2. Flood Hazard Areas. The height shall be measured from the finished floor of
any portion of the principal building where habitable space is required to be
elevated to the elevation established by the Flood insurance Rate Maps
recognized by the Building Department as part of flood safety requirements
and maps adopted by City Council. Notwithstanding the building elevations
established by the Flood Insurance Rate Maps, the minimum required first
floor finished floor elevation for the interior living areas of all new structures
shall be at least 6.27 Mean Sea Level consistent with the Public Works
Department standard for bulkhead elevation."
Determining what the natural profile of a site is extremely difficult when the grade
has been altered by past development or use of the property. Nevertheless, this
section provides some guidance when the grade has been altered and it
identifies other grades to be used under specific circumstances.
1. Grades established by a grading plan for a subdivision
Typically, new subdivisions involve mass grading to create roadways and
level building sites. The finished grades are then used to measure building
or structure height with the development of the particular tract. The Code
permits the finished grade to be used under this circumstance.
2. Grades created without a grading plan or map
The Code specifically directs planners to use existing grades and contours
of the site and surrounding lots in their best effort to determine the natural
profile of the site. When retaining walls or filled surfaces are present and
were created prior to 10 -12 -1972, the finished grade is used as the
baseline for measuring structure height. Artificially lowered grades such as
basements or wine cellars are not to be used to measure height. This
provision has been more broadly applied through the years such that no
excavated grades are used to measure height today.
3. Grades in flood hazard areas
The grade for the purpose of measuring height is increased to 6.27 feet
above mean seal level (MSL) measured in the 1929NGVD for habitable
portions of residential structures since the finished floor may not be below
this level. In essence, those residential properties are not penalized in
terms of height for providing mandatory flood protection. The increased
grade requirement does not apply to uninhabitable areas such as garages
and the height of these portions of the structure is measured from natural
grade. Within the Cannery Village /McFadden Square area, commercial
buildings are also required to elevate the lowest inhabited finished floor
and the height limit is measured from the 6.27 feet above MSL. As with
the residential garages, parking areas and parking garages do not have to
elevate above 6.27 feet above MSL and the height limit is measured from
the natural grade as opposed to the elevated portion of the building.
Issues
The primary difficulty in implementation of the height limit is in the determination
of what grade should be for the purpose of measuring height when a site is
developed or otherwise altered. Applicants are increasingly requesting a grade
determination based upon their belief that the existing elevations and contours of
the site and its surroundings were excavated and do not represent the "natural"
profile of the site. Estimating the historic grade is difficult when limited or no
information of past grades exists. Most of these requests relate to sites that were
developed prior to October 1972, and it is a rare event to have a grading plan
that shows the natural profile of the site and proposed grades at the time of
development. In looking at many sloping properties today, retaining walls are
evidence of excavation and applicants want to use the prior natural grade to gain
additional height for their proposals to increase property values.
History
The history of the evolution of the definition of grade and building height tells an
interesting tale. Prior to 1950, there was no definition of grade within the Zoning
Code and the height of a building was 'the vertical distance measured from the
average level of the highest and lowest point of that portion of the site to be
covered by the building to the ceiling of the uppermost story." In 1950, the
definition was changed such that the upper measurement was taken from the
"topmost point of the roof." In 1965, a definition of grade was adopted and the
average level of the portion of the lot covered by the building was again used,
however projecting balconies were included in the building coverage. Artificial
grade was specifically excluded from use unless it was authorized by the
Planning Commission. The record from 1965 does not explain why this change
was made, but staff theorizes that it was may have been response using the
grades of excavated surfaces when property owners desired to build up.
In 1972, the City first used the term "natural" within the definition of the term
grade. Ordinance No. 1454 states: "For the purpose of measuring height, the
grade shall be natural grade unless the Planning Commission approves a
grading plan or map, or a grading permit has been issued on or before the
effective date of this ordinance, under which circumstances grade shall be
finished grade as shown on the plan or map so approved..." This standard
permits the use of finished grade only for prior approvals issued by the Planning
Commission; otherwise, natural grade (which was not specifically defined) is
used. The changes in 1972 also included the Planning Commission's ability to
establish the grade when the natural grade or finished grade was determined to
be "inappropriate or unworkable" by the Commission. The procedure was revised
in 1991 to require a Site Plan Review application subject to 4 findings. This
procedure remains in effect today. The definition of grade above was used until
1992 when it was determined that the definition was unclear and unworkable
since the term "natural" was not defined.
In 1992, the City Council defined natural grade to be the "unaltered natural
vertical location of the ground surface." They also re- drafted the definition of
grade and broadened the use of finished grade. Previous standards prohibited
the use of artificial surfaces (finished grades) and then allowed their use with the
approval of the Planning Commission. The change in 1992 permitted the use of
any finished grade when retaining walls or filled surfaces were used for the
purpose of measuring height prior to October 12, 1972. Why this aspect of
clarifying the code was done is not in the clear record. It may have been done by
design or it may have been inadvertent, but staff theorizes the provision was re-
drafted to address artificial grades created prior to 1972 without the approval of
the Planning Commission. The standards adopted in 1992 are identical to today's
regulations although they have been reorganized and re- codified since.
Summary
Natural grade is what it is defined to be when it is applied to a specific
development proposal. The Code is clear that retaining walls or filled surfaces
are to be used and it is equally clear in that structure height is not to be
measured from an excavated surface such as basements and wine cellars, which
have been used to artificially lower the ground surface. Applicants ask that
existing grades, retaining walls, old building plans, street improvement plans and
old air photos to be used to indicate of some level of excavation. Several
questions arise...
• Does the Code permit the use of air photos or other information when it
clearly states that the Department shall use existing on -site elevations and
contours, as well as the elevations and contours of adjoining and nearby
properties?
• If historical air photos are used, what year should be used? Should the
grades of the 1960's, 1940's, 1920's be used?
• Does the provision that prohibits the use of excavated surfaces limited to
areas lowered artificially due to basements or wine cellars or other similar
structures? Does it apply to excavated areas due to the construction of
retaining walls for the purpose of creating a level building site?
In the past, staff and the Planning Commission have used any information,
including air photos, to assist in the determination of what prior grades were. The
prohibition of using excavated surfaces and the use of filled surfaces including
foundations and retaining walls has been consistently and broadly applied for
many years.
Natural grade can be a difficult concept when viewed from the outside. A
property is judged by its physical attributes and owners and neighbors formulate
expectations about a property based upon what they see. Designing a building or
structure to a grade that has not been seen for 20, 40 or 80 years, although
potentially beneficial to a property owner, will contradict the expectations
neighbors and the community.
Staff also believes that unequal application of the height limit is possible since
determining the natural profile of a site is subjective when unclear or limited
historical data is available. Finally, the administration of a system using historical
and oftentimes uncertain grades can be abused with faulty or inaccurate
information. As time goes on, the system relies more heavily upon the retention
of all surveys and grading plans so someone can use that information for a future
design.
Finally, recent occurrences have revealed an exploitable weakness in using
"existing" or "natural" grade for the purpose of measuring height. During the
process of new construction, over excavation of the land to build a foundation
essentially removes the grade used to measure height. Once this is done, staff is
wholly reliant on the survey and plan information in the construction documents
to insure a project's compliance with height limits. This has lead staff to conclude
that a system using a more permanent benchmark may be preferable.
Staff would like the Commission's support to examine different methods of
measuring and administering building and structure height. Staff would not like to
see a relaxation of height standards, unless the Community wanted it and the
Council directed it, but we would like to pursue a system that is easier to
understand and administer while meeting community expectations.
Prepared by: Submitted by:
P&4M (4�
mes Camp ell, Sen' r Planner Patricia L. Temple, Plarfnihg Director