Adaptive reuse projects breathe new life into old buildings. The Drift Hotel, a boutique hotel with its street-facing Dawn café and Dusk craft cocktail bar located on Santa Barbara’s State Street, just two blocks from Ashley & Vance Engineering’s (AV) Santa Barbara office, is a remarkable example of a successful urban renewal project.
AV structural principal engineer Paul Belmont and civil principal engineer Bruce Jones were key players on this design team.
Adaptive Reuse
Originally built with unreinforced masonry, the structure suffered damage in the 1925 Santa Barbara earthquake and has been rebuilt and occupied by numerous tenants over the years. Recently, developers purchased the property and have revamped the historic building into the Drift Hotel.
“Adaptive reuse is one of my favorite types of projects,” says structural project engineer Paul Belmont. “I like taking old buildings, peeling back the layers, and opening them up. Buildings built 100 years ago are all different. The engineer has to be flexible and come up with unique solutions.”
To bring the 100-year-old building up to modern standards, the design team did a complete unreinforced masonry retrofit, designing a code-compliant, three-story concrete structure, then connecting the original brick to the concrete using rebar and epoxy—a procedure typical of unreinforced masonry projects. Key challenges on both the civil and structural sides included Santa Barbara’s stringent stormwater requirements, historic building materials, and a compact lot.
Onsite Stormwater Retention for 1-inch Storms
Unique to California’s Central Coast is Santa Barbara’s specialized stormwater quality control system, which civil project engineer Bruce Jones has experience navigating. Bruce explains, “During a 1-inch storm, projects of this scale are required to capture stormwater from all impervious surfaces, collect it to a central location or distributed locations, and infiltrate it back into the ground. Our overview task was to find a way to achieve this integration on a zero-lot-line project—where the entire lot is covered by a building.”
The solution was an underground retention chamber, a buried plastic chamber surrounded by geotextile fabric and rock, that sits beneath the new lobby. Designing this required considerable coordination, especially because the foundation turned out to be sandstone boulders.
The civil, structural, and geotechnical engineers worked together to find room on-site for the underground retention chamber without reducing the capacity of the footings.
Retention Chamber vs. Outdoor Planters
Bruce and the civil team worked with the plumbing engineers to design a collection system from all roof downspouts, through the walls, to an underground distribution manhole to prevent system backups from overwhelming interconnected systems.
Bruce says, “If we had the space to do an outdoor planter treatment box, which is typical, a lot of the concerns about overflow wouldn’t have been there. But an above-ground feature would have affected the flow of the lobby area, which was already space constrained.”
Designed to carry a 100-year storm, the piping system included an outlet pipe running from the distribution manhole to the adjacent city parking lot.
Updating the City Parking Lot
Updates to the city-owned parking lot involved the City of Santa Barbara in a way they’re normally not involved with private development. Because City regulations assign every land parcel a treatment requirement based on a tiered system dictated by the amount of removed and replaced impervious hardscape, decisions about the parking lot affected the stormwater tier level of the work in the lot. To keep the project as a tier 2, AV worked closely with the city to minimize the area of new and replaced impervious surface. Saving both time and cost, this additional effort greatly benefited the project since only minor stormwater improvements were required. Had the project been categorized as tier 3, the entire lot would have been required to receive costly stormwater treatment.
This intimate coordination was both educational and helpful for city staff and the design team; both sides had to understand the challenges, effects, and related costs associated with each tier’s requirements. Bruce notes, “This was a unique project because both sides worked together to meet regulations while reducing the impacts on both sites.”
Pouring Concrete with Surgical Precision
Boulders were cut flush with interior walls and new concrete walls were poured down into board forms to remedy the original sandstone boulder foundation. Paul explains, “We cut back the floor 12 inches, then poured concrete, added anchor bolts and new hangers. We added rebar dowels 18 inches on center into the bricks to attach the old brick to the new concrete. It was very surgical. You can’t shake an unreinforced, 100-year-old building. You can’t use impact tools. But the concrete turned out so well, the architect decided to leave the structural concrete exposed as part of the project.”
Other retrofits included removing the rotten wood floors and pouring a slab on grade foundation. Floor framing and other elements were reused as architectural features as much as possible.
A Tall & Skinny Retrofit
Structural analysis was performed in multiple rounds to understand the exact weight of the three-story concrete and brick building. Paul notes, “Because the length and width of the diaphragm is so long and skinny, the building just wants to bend. Two concrete walls 120 feet apart in a building only 40 feet wide was a challenge. Sometimes we had to think in completely different directions. For example, a third of this building is brand new so we added a three-story brace frame in the middle.”
Bringing the Vision to Life
“Back in 2019,” Paul says, “the developer and I crawled into the attic, out an access hatch to the roof, where we eventually put the penthouse addition. We were looking down on State Street and the developers said, ‘Wouldn’t this be awesome? To have a deck or rooftop bar or something?’ It was fun to sit there, three years later, on that exact balcony and realize we got there. The best, most rewarding part of the project for me was being there, from the start to finish, and being part of the team.”
Professional Photography: ©Adiazphoto
