Des Moines’ East Village is changing. Urban infill and adaptive reuse have revitalized the district with apartments, retail options, and office spaces. 111 East Grand is the latest addition to an area on the upswing.
Our client, 111 East Grand, LLC represents a joint venture among JSC Properties, Rypma Properties, Christensen Development, and Ryan Companies. We had recently completed several nearby mixed-use buildings and parking facilities with the team.
The trust those projects built gave us the confidence to suggest a mass timber strategy for their new development. Given the surrounding revitalized building stock, timber seemed like the right material for conscientious ground-up construction. The 4-story structure locates three floors of commercial office space over street level retail.
Our clients asked themselves two critical questions: ‘what will our tenants be like, and why will they want to locate in our project?’ Market studies suggested that prospective tenants could include retailers and professional firms seeking a unique location in a hip downtown area to attract clientele and talent, respectively. For both target tenant types, high-quality design would be a justifiable investment. When we suggested that a slightly ‘edgy’ building might be appropriate, our client reminded us that ‘cutting edge is ok, bleeding edge is not.’
111 East Grand, LLC
Des Moines, Iowa
Where We Started
We made sure to substantiate mass timber’s potential when we suggested it. The team visited Minneapolis’ T3 office building to get a grasp on mass timber’s spatial qualities and we facilitated a cost/benefit review for the owners to assess the value of providing ‘something special.’
Previous mass timber buildings had used Cross Laminated Timber (CLT) and Nail Laminated Timber (NLT). After interviews with various suppliers, the team decided to pursue Dowel Laminated Timber (DLT) for 111 E. Grand. The timber supplier we selected had already made substantial capital investment into the technology, allaying owners’ concerns about risk.
DLT is prevalent in Europe and recently found its way to North America. In DLT, a manufacturer hydraulically inserts hardwood dowels into softwood dimensional lumber. The hardwood expands upon reaching moisture equilibrium and creates a friction bond with the softwood. This application greatly reduces the need for glue and drastically decreases off-gassing upon fabrication.
What We Did
We followed an Integrated Project Delivery (IPD) approach. During the design phase, we shared the Building Information Model (BIM) with the mass timber supplier. That allowed the supplier to create precise shop drawings detailing each column, beam, and panel. We then shared the model with the general contractor, who combined it with the consultants’ models. Virtual Design and Construction (VDC) meetings enabled the team to see where conflicts would occur among different systems. Finally, just prior to construction, our mass timber engineers provided erection drawings to choreograph a fast-paced installation.
A kit-of-parts approach allowed the entire structure to be erected within a 7-week period. A steel or concrete structure would have added an additional 6 weeks to the schedule. Time is money. Once the precast concrete portion of the project was complete, two of the mass timber team remained on site to lead a small crew of local carpenters. The supplier shipped the DLT panels in trucks timed to the installation sequence, arriving ready for its cargo to be lifted into place.
Despite the rectilinear footprint of the building (265’x65’), the structure was erected in separate phases; as three towers moving east to west. This enabled the crane to occupy the footprint of the building and transfer west into the staging area, eliminating the need for any road closures.
How it Works
111 East Grand’s mass timber strategy has yielded several benefits. It is technically a hybrid system, relying on a precast concrete service core to buttress against lateral forces while housing the stairs, elevators, mechanical shafts, and utilities.
Off-site fabrication paid off during construction, minimizing disturbance, crew size, and the cost of operating during one of the worst Iowa winter in years.
Mass timber brings substantial environmental benefits. 1,180 cubic meters of timber was used throughout the building structure. That’s 284 tons of sequestered carbon and 1,042 tons of sequestered CO2. To translate to experience, our impact would be the same as 170 cars being kept off the road for a year, or the energy of operating 75 single family houses in a year.
The wood’s refined aesthetics enable it to remain exposed as an interior finish. This minimizes tenant improvement work (like dropped ceilings and column wraps) while enriching occupants’ visual, tactile, and olfactive experience. Each tenant floor is provided with restrooms, a shower room, and locker rooms to promote walking and biking. Operable windows allow natural ventilation and balconies on the west take advantage of impressive views towards downtown.
The lasting benefits of carbon sequestration and biophilia will contribute to occupant health and provide a sustainable long-term work environment.