Item 4 - Staff Report.Window Materials
PREPARED BY: Sean Mullin, AICP
Planning Manager
TOWN OF LOS GATOS
HISTORIC PRESERVATION
COMMITTEE REPORT
MEETING DATE: 10/22/2025 ITEM NO: 4
DATE: October 17, 2025
TO: Historic Preservation Committee
FROM: Joel Paulson, Community Development Director
SUBJECT: Consider Providing Staff with Direction on Window Materials. Project
Location: Town Wide. Project Planner: Sean Mullin.
RECOMMENDATION:
Consider providing staff with direction on window materials.
DISCUSSION:
Window replacement is a common request discussed with property owners of historic homes.
When replacement is necessary, staff works with property owners to encourage like-for-like
replacement with either wood windows or metal-clad wood windows. When details are
provided ensuring that the window replacement will match the existing windows or be
historically appropriate for the residence, the work is completed through the Building Permit
process and is not referred to the Committee for review. Staff reviews proposals for window
replacements using the Residential Design Guidelines, which provides the following
recommendations related to window materials:
3.7.3 Match window materials to the architectural style and to the surrounding
neighborhood
• Wood windows are common in Los Gatos. Wood is still the desired choice for styles that
traditionally used wood. However, today there are some window materials, such as vinyl
clad wood windows that are not noticeably different from wood at a short distance.
4.8.2 Building Materials
• Composite, synthetic, metal, vinyl, plastic or fabricated/ imitation wood products,
painted brick or imitation used brick will generally not be approved. However, some ex-
ceptions may be made on a case-by-case basis when the decision-making body
determines that the replacement is consistent with the appearance of the original
material, and that a lay person would be unlikely to discern the difference. The burden
of proof will reside with the applicant. Material samples, photographs, and specific
PAGE 2 OF 3 SUBJECT: Window Materials DATE: October 17, 2025
locations where the material may be seen in use will all assist in the evaluation of
alternative materials.
4.8.4 Windows and Glass in doors
• Windows should be constructed of real glass, and window frames should be constructed
of real wood - not vinyl, metal, or plastic. Wood sashes may be vinyl or metal clad if the
window frame and dressing is designed consistent with the historic context of the
building.
The Guidelines emphasize the use of wood windows but allows exceptions for alternative
materials when they are not noticeably different from wood at a short distance, found to be
consistent with the historic context, and consistent with the appearance of the original material
where it would be unlikely to discern the difference.
Property owners are often looking to replace windows with alternative materials that are more
durable than wood, often wood-clad products with a metal or vinyl exterior. These materials
are more resilient to weather and require less maintenance than wood. The potential drawback
of these alternate materials is a less-than-authentic appearance.
Fiberglass-wood composite windows have been presented to the Committee many times over
the last five years. While there were initial concerns with the product, evidence has been
presented showing the benefits of the material, such as its genuine wood-like appearance,
paintable surface, historic profiles, and easy maintenance. Because the Residential Design
Guidelines predates this material and is therefore silent on its use, staff has referred projects
involving the composite to the Committee for review. The Committee generally confirms that
the profile, detailing, and look of the window will match the existing window or the historically
correct window and recommends approval.
In staff’s review of like-for-like window replacements on historic homes, the same evaluation
criteria are used, albeit for wood or metal-clad wood products. Given the frequency of the
request and the merits of the product, staff recommends that the Committee consider
providing direction to staff to utilize the same evaluation criteria for window replacements and
include consideration of fiberglass-wood composite materials without referral to the
Committee. As is the current practice, window replacements that would result in a change in
exterior appearance that does not align with the evaluation criteria would continue to be
referred to the Committee for review.
CONCLUSION:
Staff recommends that the Committee consider providing direction to staff to utilize the
evaluation criteria consistent with the Guidelines for window replacements and include
PAGE 3 OF 3 SUBJECT: Window Materials DATE: October 17, 2025
consideration of fiberglass-wood composite materials without referral to the Committee. Staff-
level approval of fiberglass-composite wood windows would reduce the Committee’s and
staff’s workload, free up agendas, and allow residents to proceed through the permit process
more efficiently.
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