The redesigned plaza configuration at 801 Grand Avenue in Des Moines, Iowa, features two tiers that gently transition the space and provide multiple seating options. The redesign incorporates both new and reused granite pavers, planters, and wall cladding.
photo credit: Elizabeth Carrie

When challenges occur, the wise often realize opportunities found in their midst. Such was the case for 801 Grand, Iowa's tallest building located in downtown Des Moines. After waterproofing issues were detected, remediation was required for 801 Grand. Initially, the property owner was solely focused on correcting the problem. But when landscape architecture firm Confluence of Des Moines presented the potential to redesign the site, the owner realized the great opportunity to give the site a fresh, new feel. Confluence developed multiple concepts, and after seeing how the space could be transformed, the owner agreed it was time to give the site a face-lift.

Black and Kenoran sage granite pavers highlight the main pedestrian walkway at the east High Street entrance. Custom decorative railings, Selux MTR square column lights and Baltic brown granite columns with decorative planter bowls along the custom designed fence give this secondary entrance an updated appearance.
photo credit: Elizabeth Carrie

A 31,000 square-foot plaza surrounds the 44-story 801 Grand, providing a gathering space for building occupants and pedestrians. More than 20 years after its original construction, the plaza required remediation. The original waterproofing had begun to fail, allowing water to leak into the garage and finished spaces below the plaza. To address the waterproofing issues, most of the existing site materials at the plaza needed to be removed. Confluence was retained to lead the renovation of the plaza and streetscape. A complete overhaul of the plaza area created a more inviting space – as well as more of the "grand" exterior one would expect at such a property. The plaza redesign softened the site and created definition between the building and plaza.

Custom-designed and internally illuminated signage fabricated by ASI Signage reinforces the 801 Grand brand at all four corners of the site. Here, at the corner of 9th Street & High Street, the signage is incorporated into the new extended portion of the wall. Custom railings are inspired by the 801 Grand logo.
photo credit: Confluence

Design Plan
Confluence's site redesign began in August 2012 and incorporated additional green space, granite paving, granite planters and other site elements to soften the space and create the desired definition between the building and plaza. Features of the new site design include an upper and lower plaza for outdoor gathering on the building's east side. The site redesign also implements strategies to manage tenant and visitor traffic around the building.

This rendering by Confluence shows the 801 Grand conceptual redesign. A tiered plaza helps make the space more approachable. Sloped planters maximize the green space and help add a soft element to this urban space. The walkway immediately adjacent to the wall/railing along High Street (right) is a main thoroughfare. Reconfiguring the corner of the plaza (front center) reinforced the new plaza design and streamlined pedestrian traffic.
image credit: Confluence

Creating an inviting plaza was a primary design goal. The existing plaza space felt tired and disconnected from the adjacent pedestrian areas, and the existing streetscape felt cold and unapproachable. The existing upper plaza was all one level, so the seating area was much higher than the adjacent sidewalk. The differences in elevation accompanied with the railings and plantings that separated the two spaces made the plaza feel uninviting. The owner wanted to create a space that blurred the lines between semi-private and public space so pedestrians and people working out of neighboring buildings also felt free to enjoy the space. By creating a tiered plaza, Confluence eliminated the need for railings to define and close off the space. The tiered area smoothly transitions down to the adjacent sidewalk. Sloped plantings maximize the visible green space and help achieve the softer look desired. The goal of creating a more open appearance extended beyond the plaza to the building entrance itself. Before the redesign, large raised planters extended the length of Grand Avenue. The planters blocked access along the south edge of the block and didn't align with the pedestrian circulation of the adjacent blocks. Grand Avenue is one of two main vehicular circulation routes through downtown, but the existing streetscape configuration made the area feel like more of a back-door entrance. The redesign put the Grand Avenue entrance to work full time, solidifying this space as the front door to downtown's premier office location.

A new, more open Grand Avenue streetscape feels more inviting to visitors and resolves pedestrian circulation issues that plagued the old design. The redesign emphasizes the Grand Avenue entrance to work full-time and solidifies this space as the front door to one of downtown's premier office locations. A series of granite bowls on pedestals, containing purple coneflower, "Autumn Moor' grass, "Gladiator' and "Globemaster' allium, and "Magyar' ginkgo, march along the now unencumbered Grand Avenue streetscape. The raised granite planters near the building are home to "Pumila' astilbe, "Grape leaf' anemone, "Montgomery' astilbe, black cohosh and "Cherry Tomato' hosta.
photo credit: Confluence

Confluence removed the existing raised planters and pushed the curb line south to add bump-outs at either end of the block. This created a vehicular drop-off for employees and visitors, reinforced the 801 Grand identity and relieved some of the traffic congestion at the north entrance to the building. A series of granite bowls on pedestals march along the now unencumbered Grand Avenue streetscape, and pedestrian circulation flows freely between 801 Grand and the adjacent blocks.

Baltic brown granite pedestals and planter bowls containing seasonal annuals separate the two levels of the upper plaza. The custom stair rails were fabricated by Cox Design & Metal Fabrication and the stair lights are by Bega USA. Advent created the custom wall sconces. The raised planters between the pedestals contain "Crimson Fans' mukdenia, Deutschland astilbe, and Skyline honey locust.
photo credit: Elizabeth Carrie

Durability, Quality Critical
Granite was selected as the building material for the paving, stair treads, building column base, wall cladding, planter curbs and planter bowls. The choice of granite helped meet two important goals for material selection.

"Durability of materials was very important to the owner," said Jill Boetger, project manager, Confluence. "Also, the quality of exterior materials needed to be consistent with the caliber of interior materials and Class A office space at 801 Grand. Granite met both of these requirements."

The lower plaza provides an alternative seating area with Baltic brown granite cladding, wall caps, pedestals and decorative bowls with seasonal annuals. The raised planter in the front is home to "Gold Dew' tufted hair grass, "Raspberry Wine' bee balm, "Caesar's Brother' Siberian iris, "Butter and Sugar' Siberian iris, and "Skyline' honeylocust. The raised planter in the back center, one of eight on-site hosts "Pumila' astilbe, "Grape leaf' anemone, "Montgomery' astible, black cohosh and "Cherry Tomato' hosta.
photo credit: Elizabeth Carrie

During the schematic design phase of the project, Confluence brought in trusted partner Coldspring for supplying more than 18,800 square feet of granite for the project. During this phase, they offered materials selection and pricing assistance as well as detailing suggestions to aid in fabrication and construction.

They were able to provide the colors, quality and schedule needed for the project. Colors included black, Kenoran sage and Baltic brown, which is one of the two primary granite cladding materials on the building. The previous plaza had been primarily Baltic brown.

"In the redesign, we chose to define the plaza space by selecting a contrasting paver material. Black granite in a variety of finishes was selected to create this contrast," said Boetger. "Kenoran sage provided a lighter accent paving that tied nicely to the tones found in the Baltic brown on the building."

The plaza redesign created a more open pedestrian space, with ample seating areas. The openness of the space invites tenants of neighboring buildings as well as passersby to sit and enjoy the space.
Photo Credit: Elizabeth Carrie

Creating an inviting plaza was a primary design goal for Confluence. Before the redesign, the existing plaza space felt tired and disconnected from adjacent pedestrian areas. The large stair at the south end of the plaza was eliminated in the redesign in favor of a central staircase and a tiered design that allowed for the elimination of most of the railings, which, due to the brass accents required labor-intensive maintenance.
photo credits: Confluence

Reuse and Reliability
Confluence achieved continuity between the building and site by cladding the vertical walls in Baltic brown. The design team decided to re-use as much of the existing granite cladding as possible in the redesign. This decision was made for a variety of reasons, including environmental considerations, budget and schedule. Only two quarries in the world supply Baltic brown. As a result, acquisition of large quantities of new material would have impacted the schedule for reconstruction.

The masonry contractor, Seedorff Masonry, created a detailed inventory of all existing wall cladding and caps before the existing plaza walls were removed. The design team worked closely with the masonry contractor and the granite supplier to develop a plan to reuse the Baltic brown cladding in a thoughtful layout that accounted for the slight variations in coloration between the new and original cladding.

"Close coordination with our suppliers was needed to document where the pieces of Baltic brown from the building's cladding and the original site wall came from in order for the granite to be reused," explained Abby Rodewald, landscape architect-in-training with Confluence. "The same level of coordination on shop drawings ensured that new grades and cladding matched those that were being reused."

The 801 Grand upper plaza acknowledges the street and invites passersby to stop and sit. Freestanding tables and chairs provide a comfortable place to have lunch or read a book. The plaza is intimate enough for one or two people to enjoy, while still being large enough to accommodate a larger group or event. The granite stair treads are black granite, while the granite cladding, wall caps, pedestals and decorative planter bowls with seasonal annuals are in Baltic brown. The lower planters, adjacent to the stairs, contain "Gold Dew' tufted hair grass, "Raspberry Wine' bee balm, "Caesar's Brother' Siberian iris, "Butter and Sugar' Siberian iris, and "Skyline' honeylocust.
photo credits: Elizabeth Carrie

Inventorying the granite for reuse was critical on the front end of the project. Cladding was removed from the building façade, site walls to remain and site walls to be demolished. Some of the cladding was to be returned to its original location, but adjacent paving was being reworked. In most cases, the size of the granite didn't allow for much variation between existing and proposed grades. Typically, the reused granite only extended an inch or two below the existing grade.

"We also needed to carefully consider how and where to reuse salvaged granite so that we could reuse the most granite possible, while being strategic so the variations between new and old granite looked intentional and thoughtful," said Boetger. "For example, the existing north wall that runs all along High Street was extended on both the east and west ends."

To make the new extensions appear as though they were part of the original construction, Confluence reused salvaged panels. These are some of the tallest panels on site, so only a few of the salvaged panels were large enough to work in these locations. Along the same wall, Confluence made the existing columns deeper to accommodate new planter bowls. Baltic brown was chosen for the 44 large planter bowls that sit atop granite pedestals accentuating the architectural grid. Confluence designed the unique planter bowls and coordinated with the supplier to find the proper sourcing to import them. "Reliable sources for importing the planter bowls were critical to accommodating the project's budget and schedule," said Boetger.

Throughout the construction and installation phase, project scheduling, sequencing and phasing proved essential, as the building remained occupied during construction. Crews from JE Dunn Construction and granite installer Seedorff Masonry, both of Des Moines, had to maintain access to the building's entrance throughout construction.

"Because it is an existing building with a large number of employees in a downtown area, important considerations included site access, visibility to the entrance, skilled laborers working with somewhat delicate materials without blocking traffic or people – all required excellent coordination between the designer, fabricator and contractor," explained Rodewald.

Completed in December of 2013, the revamped plaza and site feel fresh, welcoming and new. The addition of contrasting materials in the landscape provides definition between the building and the plaza, and the south entrance on Grand Avenue now has the "grand" feel it was missing in the original design. With obstacles turned into opportunities, 801 Grand now offers a more open and inviting space for its employees and tenants.

Project Team
Landscape Architecture: Confluence
Structural Engineer and Waterproofing: Simpson Gumpertz & Heger
Irrigation Consultant: EC Design
Civil Engineer: Bishop Engineering
Graphic Designer: Selbert Perkins Design Collaborative
General Contractor: JE Dunn
Electrical Design/Build Contractor: Baker Electric Inc.
Structural Engineer (Granite Cladding Anchors): BDC Structural Engineers
Construction Signage & Barricades: Bonnies Barricades Inc.
Landscape Contractor: Country Landscape Inc.
Handrailing & Stair Railing Fabricator: Cox Design & Metal Fabrication Inc.
Caulking Contractor: Midwest Caulking
Earthwork and Utilities: Kelly Cortum Inc.
Signage Fabrication & Installation: ASI Signage
Waterproofing Contractor: McGill Restoration Inc.
Interior Insulation Contractor: Mid-Iowa Environmental Corporation
Masonry Contractor: Seedorff Masonry Inc.
Irrigation Contractor: T & T Sprinkler Service Inc.
Construction & Materials Testing: Terracon Consultants Inc.
Mechanical Design/Build Contractor: The Waldinger Corporation
SWPPP Monitoring: Soil-Tek
City's Electrical Contractor (Street lights): Mid-American Energy, Burns Electric
Existing Wall Demo/Removal: Iowa Concrete Cutting
Construction Signage Fabrication & Installation: Vita Signs
Bituminous Setting Bed Installation: Grimes Asphalt

Suppliers:
Rebar/Reinforcing: Ambassador Steel Fabrication, Inc.
Temporary Fencing: American Fence of Iowa
Granite: Coldspring Granite
Concrete: Concrete Technologies Inc.
CU Soil: Corell Contractor Inc.