961 Gravenstein Highway South

Katherine Austin, AIA, Architect Self
179 SE Rice Way
Bend, Oregon 97702-1507
(707) 529-5565
Katherine Austin
Business Phone: (707) 529-5565

Project Location: 961 Gravenstein Hwy. South, Sebastopol,CA
Completion Date: 06/01/2017
Owner: Gravenstain Mixed-Use, LLC, Chris Pellascini Managing Partner

Architects Involved:
Mark Golik, Job Captain

Additional Team:
MKM & Associates, Structural Engineer, Rohnert Park, CA
Doble Thomas Assoc., Civil Engineer, Healdsburg, CA
Parker Smith, Landscape Architect, Santa Rosa, CA
PJC & Associates Geotechnical Engineer, Cotati, CA
Illingworth & Rodkin, Acoustical Engineer, Petaluma, CA
WMRA, Gary Waters, Accessibility Consultant, Santa Rosa, CA
Zero Energy Associates, Solar and Mechanical, Sebastopol, CA
North Coast Utility Design, Windsor, CA
DEVCON Construction, Project Manager, Petaluma, CA

Project Description

961 Gravenstein Hwy, Sebastopol, is a $4.5 mm mixed-use building of 8 residential units above, facing the Laguna de Santa Rosa, and 8 retail units below facing the street. The site is narrow and long and oriented on a north south access. It slopes in two directions, creating a challenge for both pedestrian and vehicle access. To the rear it slopes irregularly allowing for a subterranean garage entered at the rear north end. Additionally there is surface parking in the rear that completes the lot used by the adjacent affordable housing development. An elevator provides access to all levels including walkways along the rear of the retail and front of the residential levels.

The site previously was the location 2 derelict shops with front loaded parking. The overall site-plan was designed in conjunction with the local Non-Profit developer that built the adjacent residential neighborhood to the east. Both were approved jointly before the recession. Only the affordable housing had funds to build during the recession. The mixed-use building owned by a consortium of local developers was revived after the recession. At that time it went through extensive review and appeal process to reach its final design. As a result all 4 sides of the site were fixed.

The intent was to provide an urban, pedestrian friendly, mixed-use project that would provide both middle market housing and sales tax for Sebastopol. The location is indicative of 1960’s strip mall and parking-front development. Our project sought to turn that tide and provide an example for future development along this corridor. It is half commercial and half residential within walking distance to the center of town.

Due to the orientation the challenge to protect the south and west facades from sunlight were met with active shading devices, inset doors, and low e glazing in both residential and retail spaces as well as the option for natural cross ventilation in both areas.

A full solar array extends the entire length of the roof hidden by the parapets that offsets electrical use for all tenants. Electrical appliances were installed to use that solar power. Electric mini split units provide heat and cooling in all spaces with their units on the roof hidden from view. This project exceeds the California Green Building Standards in Tier 1. The ventilation for the garage is a combination of inflow from the decorative openings on the east side and exhaust on the roof so that no mechanical equipment other than meters are visible.

Lastly one fully accessible deed restricted unit is provided and the remaining 7 are fully adaptable. The elevator in the rear provides access from the garage level to both retail and residential level. A path of travel is provided by walkways on the east that also provide semi private deck areas for the residences and additional access to the retail spaces. The access was the major challenge for the project due to the sloping site and working with the existing conditions

Design Challenge

There was both a physical challenge and a political challenge in realizing this project. Physically the delay in the project caused the adjacent residential project to be built several years before. Thus all 4 sides of the site were existing, unmovable conditions. The building responds with changes in grade internally. Working on a narrow sloped site that is oriented in the opposite direction from what is optimal for solar passive design made for a challenge. Low e glass, natural ventilation and sound dampening windows were used on both levels. This is a podium style building with the garage post tension roof slab taking 17 hours to pour. Cal Trans controlled the right of way along the frontage, and working with them and the City on the lengthy pour as well as to change an awkward pedestrian cross walk and parking on the highway was an additional challenge. Meeting the owner’s need for both retail and residential on the site while providing all required parking and making the access work for both pedestrians and cars was the most difficult challenge. The building met all those challenges. This is not to minimize the political challenge of working in the very contentious environment of Sebastopol where very little gets built without appeals and court cases. The entitlements for the 16 units had been approved and delineated as condominiums in 2007, therefore the overall design remained fixed, but the look of the building went through four iterations with the Design Review Board and an appeal to the City Council. That said the design remained true to the Architects design sense and the team is quite proud of the result. The owner was happy to have all units leased even before construction was complete.

Physical Context

Sebastopol is a small city of 7,500 people. It is burdened by two highways crossing through the city that serve a population of closer to 40,000 in western Sonoma County. It is a desirable location with upwardly rising housing costs. These 8 units of housing have provided some needed middle market housing and one deed restricted unit in a location walkable to downtown and many amenities. Cal Trans controlled the western frontage improvements and cross walk as this is on Hwy 116 or Gravenstein Hwy South. The east side was fixed when the residential development was built down slope. All driveways on the north, south and west were in place. Grade changes had to be accommodated within the building itself. To the north was a Foster Freeze with its attendant parking lot. It has since been repurposed into a seafood restaurant with some parking converted to outdoor seating. To the south is a strip mall. All buildings surrounding the site are oriented at an angle to 116 which cuts through at a diagonal. This caused the driveway on the north to angle awkwardly into the site.   There are strip malls and supermarket across the highway with parking in front. This is typical along the highway, even though this is within the city limits. Our development tried to introduce a more pedestrian friendly and urban approach that can be a precedent for future redevelopment in the area.   There is significant sound coming from traffic on the highway. To mitigate this both the residences and the retail spaces have sound dampening glazing as well as low e glazing to reduce heat gain. The development helps to shield the easterly subdivision from traffic noise and was welcomed by those residents. One nice amenity is a view to the Laguna de Santa Rosa on the eastern edge of Sebastopol. The major orientation of the residences is towards that view. The living and dining areas as well as the semi-private deck areas all face that view. Thus the outdoor spaces are spared the traffic sound on the western side.