Precast Solutions writer Sue McCraven asked KZF Design’s project architects of the Metropolitan Sewer District of Greater Cincinnati to discuss the steps required to build a LEED Gold structure. Michael K. Smith, RA, CCS, CSI senior architect and project manager and Dan Groene, senior project designer, talk about the project and how precast concrete became an important component for successful bidding, project planning and budgeting.
Q. How did this LEED Gold Certified project begin?
A. Smith: The owners, the City of Cincinnati and the MSDGC, wanted a LEED project right from the beginning. Because of the city’s problematic combined sewer-wastewater system, MSDGC and the EPA (Environmental Protection Agency) worked together to develop a long-term control plan as part of a consent decree to the city to reduce stormwater runoff in any new construction. Initially, the city wanted to go for a LEED Silver Certification with a vegetative roof to help fulfill this goal.
A. Groene: That’s correct. From the project’s inception and during the bidding competition — which was very stiff, by the way, with highly qualified competitors — we knew the owners intended for this addition to MSDGC’s facilities to be an outstanding example of environmentally friendly design using the best available technologies (BAT). Another important issue that was solved in the selection of precast durability was the RFQ (Request for Qualifications) requirement that building components would require only standard maintenance for the first 40 years.
Q. What does it take to put together a LEED-certified project?A.
A. Smith: It involves an intense and coordinated effort. A great many people were players on the team that put this project together; KZF has a LEED coordinator who handled all the required templates, forms and filings, as well as a detail architect, the project contractor (Cintech), AMS, Reddy Electric, an estimator, a quality controller, project architects and engineers, and the precast fabricator.
Q. How did precast help K2F in securing the winning bid?
A. Groene: Precast scores big on several points in the Cintech/KZF team’s ability to win this project. First, prefabricated wall panels reduced labor costs over alternative designs, plus we had the consistency and quality of plant manufacturing. Secondly, we were able to save budget costs when the owner decided to go from the original RFQ LEED Silver designation to LEED Gold. Once we began adding elements to meet the higher certification level, we had to find ways to cut costs for the owner. Precast provides a very energy-efficient cladding system with the high R-values we needed. And last, we knew the precast could be delivered on time and erected during bad weather to keep the project on schedule and under budget.
A. Smith: Once the city upped the ante to go for Gold (LEED certification), we had to re-examine the original design features of our proposal to see where we could save time and money and still offer a thermally efficient structure. Precast wall systems helped to achieve the credits we needed for the building’s energy-efficiency rating and, from industry conferences, we know the precast industry has worked hard to advertise and promote sustainable designs.
Q. What was your biggest challenge in this project?
A. Smith: In addition to the very tough competition to be the top bidder for the owner, this was the first sizeable design-build project to be built by the City of Cincinnati. We needed both a savvy design-build business partner in the general contractor, Cintech, and we knew we faced very discerning and pragmatic judges in the wastewater engineering group that examined our proposal. We had to be able to deliver what our proposal was promising in terms of valid green construction.
A. Groene: We knew our proposal would be judged on our credibility in delivering LEED-certified components. KZF has solid experience in developing green projects and we understood what the wastewater engineers were looking for from prior experience.
Q. What makes the architectural precast critical to winning this project?
A. Smith: Because we had to match the architectural look of the existing MSDGC facilities, we needed a brick finish but without the labor, time, cost or quality issues of real masonry construction. High Concrete developed prototypes of precast wall panels finished with half-inch-thick quarry tile brick that has better material characteristics than that of standard face brick. For example, standard face brick would absorb too much water with its clay content to work within the tolerances of precast concrete processes. The quarry tile bricks selected by the precaster use a finer gradation of clay to keep absorption rates down. Metro Brick by Ironrock Capital provided a product with higher stress and bending attributes that would perform within precast manufacturing limits.
A. Groene: As you can see from the photos at the precast plant, the architectural finish with the quarry tile brick is aesthetically pleasing and provides a sophisticated look.
Q. How important was the precaster to the success of this LEED-certified project?
A. Groene: A competent precaster was critical. You have to remember that when we bid this job, the precaster was not on board. It was only after we were awarded the contract that Cintech began negotiations with High Concrete. At that point, the precaster was tasked to provide mock-ups of the architectural finish and thermal rating we needed for the LEED Gold certification. We coordinated closely with High Concrete to develop wall samples and a mortar mix that would work for the project and satisfy the owner.
This is not a continuous precast wall panel from the bottom to the roof line. It’s more a ‘kit of parts’ with different components — from panel infills, spandrels and column panels — that are hung on the underlying structural steel framing. In other words, the precaster had to solve a number of challenges in a hurry and with a high-quality product.