Attachment 8 LRV averagingDAVIDON HOMES
HIGHLANDS OF LOS GATOS
LRV Averaging
Intent, Rationale & Methodology
Intent
The goal of LRV Averaging is to help better achieve the objective of the Hillside Ordinance — to make homes
in hillside areas blend into their surroundings so as not to create an eyesore.
Rationale
To achieve this goal of blending, we first look at the environmental backdrop of the homes. In this case,
we have a dark green & grey Oak Woodland of varying density laid against fields of golden grasses.
However, there are some exposed areas of earth varying in tone from beige to terra cotta. The key to
blending is the way these colors are visually merged. We want to avoid using a monotonic palette as much
as possible so the eye isn't drawn to it, and present variation in color to make the building blend visually.
From our experience, an LRV of 30 is very low compared to Hillside Ordinances in place across the US that
use LRV values. A review of other jurisdictions, that employ a Hillside Ordinance, revealed that few
municipalities utilize a LRV numeric value versus a more common requirement to utilize earth tone color
palettes or a reference to blend to the natural background. Those municipalities that do utilize a LRV trend
toward higher values than the LRV 30 as adopted by the Town of Los Gatos.
Noted below are the results of our survey of various municipalities:
Municipality
LRV
Municipality
LRV
Santa Clara County
45
Scottsdale, AZ
35
Town of Los Gatos
30
Cupertino
60
Morgan Hill
60
Los Altos Hills
None
Santa Barbara County
None
Milpitas
None
Santa Cruz County
None
Berkeley
None
San Rafael
None
San Jose
None
Tiburon
None
Saratoga
None
Walnut Creek
None
Orinda
None
Napa County
None
The goal of a darker LRV color creates an unintended consequence in which the designers & colorists will
trend as close to 30 as possible to avoid colors that are too dark for almost any architectural style or
potentially a homeowners' preference. That leads to a more monotone color palette making structures
stand out as a brown patch on the hillside. With LRV Averaging, a more diverse palette using the
background's earth tones is present on building facades to better blend the architecture into the hillside.
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Some jurisdictions even go further and state that LRV Restrictions may be waived entirely when an
Exemption for Sites that are Not Visible applies.
Methodology
The methodology used for the LRV Averaging starts with the paint colors. The colors are selected in
keeping with Architectural precedents and in concert with the context's color palette (dark green, grey,
gold, beige, terra cotta).
In determining LRV values, the manufacturer's stated LRV values for all paint and roofing colors are used.
Unless the manufacturer has provided a LRV for its material for masonry veneers, our Architectural
Consultants and Colorists use the "paint chip matching" method where they visually match averaged color
tone to a paint chip and ascribe that chip's LRV value to the masonry. For glass LRV, the consultants use an
industry accepted average of:
1) An LRV of 0 when the glass is reflecting trees and solid objects
2) An LRV of 20 when the glass is reflecting a day lit sky
3) An LRV of 15 when the glass is reflecting a cloudy sky
This averages out at an LRV of 11 for the windows.
With regard to the LRV Averaging process itself, the Architectural Consultants add up all the areas of each
of the facades of the building and use a "weighted average" to calculate what the LRV Average is for the
respective facade. All four sides of the building elevation as well as the roof elements are taken into
consideration for the LRV Averaging. In specific terms, the LRV value for a particular color or material is
multiplied by the area it occupies on that face. Then the total of those "weighted" numbers are divided by
the total area of each facade. The four independent sides are then averaged in total for the LRV weighted
average for the entire home.
An example of this process is noted below:
DAVIDON - HIGHLANDS OF LOS GATOS LOT # 2 — FRONT ELEVATION
MATERIAL
AREA BY
SQ. FT.
LIGHT REFLECTIVE VALUE
(LRV)
TOTAL MATERIAL AREA
MULTIPLIED BY LRV
NUMBER
STUCCO
773
APACHE TAN :50
38,650
S' ROOF
637
CALIFORNIA MISSION
BLEND: 18
11,466
BRICK
575
MC NEAR SANTIAGO: 17
11,500
GLASS WINDOW
265
GLASS: 11
2,915
SHUTTERS
21
PIKE LAKE: 17
357
FRAME & FRENCH
DOORS
165
ANDERSEN, TERRATONE:13
2,145
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WOOD, CHIMNEY
33
MISSING LINK: 11
363
CAP, FINIAL& GARAGE
REAR
27.58
LEFT
DOOR
RIGHT
29,73
AVERAGE OF ALL SIDES
PRECAST & TRIM
358
HICKORY: 35
12,530
TOTAL AREA =
2,827
DIVIDED BY
79,926
79,926/2,827 =
TOTAL LRV
28.27
The process above is repeated for each of the four sides of the home. The weighted average for each
elevation is then totaled and divided by the sum of the four elevations. The results are summarized for
each home as follows:
DAVIDON — LOS GATOS — LOT 2
ELEVATION
LRV AVERAGING
FRONT
2 %.27
REAR
27.58
LEFT
33.89
RIGHT
29,73
AVERAGE OF ALL SIDES
29,87
In conclusion, we feel LRV averaging actually better achieves the intent of the Hillside Development
Standards and Guidelines by using varied colors (chosen from the visual backdrop) on the homes' facades
so as to make them better blend into their surroundings. We hope this brief outline helps clarify Davidon
Homes proposal, but look forward to answering any questions the Council may have.
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