Design-Assist Prescription Expands Hospital

Teamwork approach keeps workflow on time for a St. Louis expansion and renovation.

A custom, unitized curtainwall system allowed innovation and flexibility to combine aesthetic, performance, and economic considerations for St. Joseph Hospital West. Here the stud panel air vapor-barrier tie-in is set before the curtainwall units are installed.

SSM Health St. Joseph Hospital West in Lake St. Louis, MO, was established in 1986 to meet the expanding healthcare needs of western St. Charles County. As the Lake St. Louis area grew and residents from surrounding counties began using the hospital’s services, a need developed for expansion and renovation. The expansion came to include a three-story patient tower adding 84 additional beds to the facility. The highly rated hospital’s ultimate goal for increasing space and upgrading the facilities was to improve the overall patient and employee experience.

The expansion design planning began in May 2015 and was finalized that October. Construction of the 24,350-sq.-ft. patient tower began in November. IWR North America, St. Louis, one of the largest specialty contractors in the United States focusing on being a building-enclosure partner, was commissioned early on during the design-assist phase as the sole building-envelope contractor.

The concentrated teamwork approach of the design-assist phase presented IWR with challenges similar to any large, complex project using the same method. This method encourages all primary parties to be involved from start to finish, enabling each participant to ask questions and make recommendations. IWR’s coordination of details, documents, transitions, and any overlap between trades contributed to the success of the project.

Streamlined collaboration and workflow was essential in keeping all activities and trades working together. The management and coordination of installation transitions of the building-envelope systems was the core factor in preventing or causing performance issues for the building during its lifespan. IWR held internal meetings twice a week with their team and subcontractors to ensure the transitions were on track and executed properly. Additionally, IWR representatives met with the general contractor, architect, and project consultant twice a month to confirm that construction was running smoothly and all parties were meeting expectations.

The sequencing of trades and tasks on a commercial construction project is critically important to the operation and completion of the project. IWR was challenged with the commercial-construction building sequence, including the time that is required to finalize the plans, develop estimates, organize project contracts, obtain permits, and begin the procurement process. Some steps were executed at the same time while others couldn’t begin until one finished, increasing the risk of delays.

The hospital’s partial south-elevation curtainwall and panelized stud framing is shown complete.


During the design-assist phase, IWR collaborated with the glazing contractor to design the custom unitized curtainwall systems. The design team started with a chassis from previous systems, and the system was modified to fit the aesthetic component of the design intent. New extrusions were made, and, in the end, a new system was designed that was specific to the needs of the hospital.

A large section of the building-envelope’s wall panels were built off-site in a controlled shop environment. The sheathing and air and water barriers were applied to the wall panels in a weather-controlled environment, allowing production to continue during winter months. Prefabricating the wall panels brings many advantages to contractors and facility managers. The factory-built wall panels allow more square footage to be erected at one time, require a minimal laydown area, and provide a better quality-control process in lieu of the traditional stick-built system. Once on-site, the pre-built units were hoisted onto anchors and connected to the building. This system was ideal for the project as it sped up the installation process, reduced field labor costs, facilitated higher performance, and provided more regular conditions for panel optimization.

Both of the rainscreen cladding systems used aluminum composite material (ACM) and phenolic panels from Trespa North America Ltd., New York, that were attached to a custom-designed, thermally isolated sub-girt system. The architect wanted an organic look achieved by using directional grain and an anodized aluminum finish to the ACM panel systems. The Trespa panels were installed in a random pattern featuring one color while rotating the panels in varying degrees. By varying the orientation, the overall look appeared to be unsystematic, meeting the architect’s desired texture and aesthetics.

A view of the partial south and east elevations complete with curtainwall, rainscreen, Trespa panels, and anodized aluminum fins in place. The Trespa panels were oriented in a random pattern featuring one color, while rotating panels varying degrees to create an unsystematic look.

The project’s successful completion was aided by a value-management log that IWR management used. The log captured the ideas generated during internal and external meetings where potential design changes, associated costs, performance, and schedule impacts related to each concept were discussed. The tracking method allowed the team to stay organized and maintain focus on moving toward the completion date. The log management also allowed flexibility with the design elements that were needed in identifying areas of opportunity to reduce cost in line with the established budget.

IWR was hired as the sole building-enclosure contractor to help streamline the design and construction process and ultimately accomplished the goal through commitment to organization and communication. The benefits of a custom, unitized curtainwall system allowed innovation and flexibility to combine aesthetic, performance, and economic considerations into a solution that met the needs of the hospital. In addition, the use of the unitized wall system for the expansion needed limited space for installation and storage. The expansion was completed in November 2016, providing enhanced facilities and medical care for families in the Missouri counties of St. Charles, Warren, and Lincoln.

— Learn more about Trespa panels.

— Learn more about IWR and the MHS Legacy Group.

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