Structural Considerations for Restoring the Historic Spheir Building

Bend Office, Project

The Spheir building in downtown Bend, Oregon, was originally built in 1917. At 7,000 square feet, it is downtown Bend’s largest historical structure. Originally constructed as a two-story, mixed-use commercial building, the prominent downtown corner has undergone various transformations. Most recently it was the home of Trivia Antiques since 1984 and is now home to Domaine Serene Wine Lounge, which opened in December 2021.

In 2019, the building’s owner embarked on a rehabilitation project to showcase the structure’s historic value and transform the space into an elegant restaurant and wine lounge. Ashley & Vance Engineering was hired to provide structural engineering services. Below, project engineer Rollston Frangopoulos explains what it took to upgrade this historic structure, retrofit the original basalt dug-out basement, and create the client’s desired atmosphere while maintaining the structure’s historic features.

Showcasing Original Materials

To transform the old retail store and neighboring barber shop into an elegant space that retained its historic charm, the design team worked to highlight original construction materials like wooden roof trusses and distinct brick walls. Modifications included removing the existing chimney, creating a mezzanine with wine storage, and adding a staircase in the center of the building.

Brick Walls & Steel Columns

Ashley & Vance Engineering was hired to design canopies that cover the exterior sidewalk, an improvement over the old fabric canopies that hid the building’s exterior features. Bolted plates and tie backs were added to the existing concrete beams above the brick walls. Steel columns add redundancy and provide ductility during a seismic event.

“When the window canopies get loaded with snow,” Rollston explains, “the diagonal tie backs want to pull against the brick structure, while the canopy will want to push against the brick. We didn’t want to load that brick structure as a lateral point load, so we added steel mullions and bolted the tie backs into the concrete beams above the brick pilasters to support the canopy independent of the brick. Now the brick isn’t seeing any load from those canopies on either side. In case of an earthquake, the brick provides gravity support and the steel helps prevent too much movement. So we have improved the seismic capacity of this building considerably.”

Long-Span Roof Joists

Part of the historic aesthetic of the Spheir Building is the exposed long-span roof joists that originally ran the length of the ceiling. They broke and lapped over two walls down the middle of the building where the original stairs were. Because the client wanted to add a mezzanine and open the space, much of the two walls were removed. Steel posts and beams were put in place to support the (E) Joists. The stairwell that ran through the middle of the space was repurposed. Some roof joists were removed to gain head height, while other joists were repurposed and/or reinforced to account for new rooftop loads.

[Caption] Left image: Starhead screws and doubled joists. Right image: Original hammered nails and single joists.

To make modern glue-lams match 100-year old wood, the construction team roughed the surfaces with wire brush. Look closely and you’ll see some trusses are doubled up to support loads coming from the rooftop units. The construction team used modern lumber and their own “antiquing” techniques to match the aesthetic. Aside from doubled joists, another giveaway is the use of star-head screws on the new “antiqued” joists while the original joists still have the original nailheads and hammer marks visible.

Accounting for Capacity in 100-Year-Old Timber

When retrofitting historic buildings, it’s valuable to preserve and reuse original wood materials because it not only maintains the rustic charm of a space, but older wood typically has a higher capacity if it has remained in good condition. In the Spheir Building, most of the existing wood was in excellent condition. “For a historic structure, I will look at how old the building is, look at old plans for construction dates and building code requirements, and I’ll give the material a higher designation in my analysis to see if it can support the new loads we’re putting on it,” says Rollston.

“Wood joists milled one hundred years ago typically have a higher capacity and are stronger than a 2×10 milled today. These days, we harvest trees, replant, then harvest them 20 years later. Because of that short growth period, twenty-year-old wood hasn’t grown to be as dense as some of the old growth trees used in this original construction.”

Historic Registry

“Because this building is on the historic registry, we had to maintain a lot of the existing structure. For example, these floors were completely taken out and put back in and the same joists were put back in. But we added new structural support because the joists couldn’t span as far as they needed to in the new design.” Joists that were taken out and couldn’t be used again were repurposed as wine racks, which helps preserve the historic integrity of the building while giving it a modern and comfortable feel.

“When we first analyzed this building, joists that were here originally spanned quite far. This made the floor somewhat bouncy. This was not a structural capacity issue, but a serviceability consideration. Nowadays, we calculate deflections to something that is tighter so it feels good for people to walk on. What governed our design was limiting deflection more so than the structural capacity of the wooden member.”

Adding Steel Beams and Stairwell

Opening up the space and adding an upstairs mezzanine meant cutting some of the existing joists and reinforcing the structure with steel beams and columns. “Because they wanted this whole space open, we utilized the stairwell to support the steel beams,” Rollston says. Thirty-foot steel columns were added from the foundation in the basement that span all the way to the ceiling. 

Upstairs in the mezzanine, the client wanted casings for wine storage, which hide the stairs behind them. “Structurally, the whole floor is supported by steel cantilevers, with double cantilevers supporting the corners,” Rollston says. “Adding the steel railing all the way around ends up working with the steel beams to further improve serviceability.”

Improving a Unique & Underutilized Basement

There’s a secret door in Domaine Serene disguised within the wall. Elegant stairs lead downstairs to the lava-stone basement where two rooms await private parties and events. Transforming this dugout storage room into two unique and elegant spaces meant digging down a few inches, supporting the cellar walls, raising the main level floor, and reinforcing the entire structure from the basement up. 

Before renovations, the dugout basement was shallow and dimly lit with packed dirt floors. The previous tenants used it for storage and prior to that, speculation (plus a few hidden doors and corridors) suggest it was part of an old speakeasy. After renovation, the basement now includes temperature-controlled wine storage, a prep kitchen, and two private event rooms: a dining room and wine lounge. 

“It was a completely underutilized space and, by remodeling the building and having Domaine Serene come in as a client, the owner really used the space well,” says Rollston. Additional spaces tucked into the basement includes an old coal chute, a back door and stairwell, tunnel, a dumbwaiter that still works, a temperature-controlled wine cellar, and a furnace room.

In order to remove the street-level flooring, they needed to shore up the basement-level retaining walls with temporary diagonal kickers. They used lasers to measure how much the retaining wall deflected while the floor was removed before putting it back in and re-supporting that wall to see how much it moved. The team poured footings, added steel columns, and raised the street-level flooring, which fully transformed the basement.  

What was the biggest challenge of this project?

“As with any existing building, a lot of the structure wasn’t exposed until we started the demo, which is well after design,” Rollston says. “So the challenge with any existing structure is always trying to interpret what you can see to the structural design. Lowering the basement floor and taking out the street-level floors was a big challenge to make sure we didn’t accidentally collapse the building in on itself.

“But the biggest challenge was getting all of these steel structures in a place that the architect was okay with. With the mezzanine structure and the roof structure, everything comes down on the steel columns and beams. We needed these beams to reach the foundation while allowing as open a floor plan as possible so the architect could achieve the functionality of the spaces that they wanted. 

“We also worked really hard to avoid seismic upgrades because that might have pushed the cost to being prohibitive. It was already an expensive refurbishment, but the client signed a lease to occupy the entire space so they wanted to utilize all of it.  

“On this project we worked with the building owner as well as the tenant, Domain Serene. Typically, the main shell of a building is done by the owner and then tenant improvements are done later. But so much of this design was integral to a winery that they probably had a lot of input early on.”

What advice for someone else with a similar project?

“Get your architects to open up as much as you can before you start doing your design because you’re going to redo the design a lot. That was one of the biggest challenges on this one. This one had so many site visits. That’s why we’re constantly taking photos of the spaces as we go to make sure that our initial assumptions from the design are still accurate.”

For more information on the Historical Building, visit:
City of Bend Historical Preservation Stories – Spheir Building, 1917