Master Translator

Ask Mary Peterein what it costs to erect blast-resistant concrete walls for a high-security downtown office building. Or how to plan the installation of custom-built life-support systems at a new aquarium tucked inside a 19^th-century train shed.

Those are a couple of the intricate scenarios she tackles on any given day.

Peterein has devoted more than two decades to translating ambitious client visions into executable plans. Her hands-on McCarthy project experiences have spanned the healthcare, education, commercial, science and technology, and hospitality sectors.

A few recent precon assignments she has overseen include the O'Loughlin Family Champion's Center at Saint Louis University, an Emergency Department Addition at Phelps Health in Rolla, Mo. and several projects for Omaha Public Schools.

The construction challenges that cross Peterein’s desk rarely fit standard templates. 

During her 21-year McCarthy career, the preconstruction phase has evolved from a narrow focus on traditional cost-estimation activities to a broader involvement in projects from the initial pursuit and well into the construction phase. “There's more overlap with construction, which helps us accelerate the project schedule so we can get the building opened earlier for the owner,” she says.

These days, Peterein and her precon teammates are go-to strategists who provide valuable data and guidance that get shovels in the ground as soon as possible.

Small-Town Activism

Peterein’s story begins about an hour south of St. Louis in the rural community of Ste. Genevieve, Missouri, where she grew up on a small farm with her parents and older brother. 

An early fascination with LEGO sets provided clues into Peterein’s future vocation, but it was a proposed landfill across from her family’s farm that sharpened her focus. “The whole neighborhood rallied to understand the impact of what was going to happen, and to fight it,” she recalls. 

The community's persistence paid off, as the project was abandoned by the developer. 

Peterein enrolled in the geological engineering program at the University of Missouri–Rolla (now Missouri S&T), where an environmental emphasis within select engineering programs was just starting to take shape.

On a campus where men outnumbered women four-to-one, Peterein joined the Chi Omega sorority to build community with other female students, and she became close friends with several sisters who were civil engineering majors. When a statics class piqued her interest in structural design, she switched her major to civil. 

During the first couple of college summers, Peterein got a taste of manual labor as she spent sweltering days working at a cement plant in Festus, Missouri, where her dad was also employed. “I came home covered in dust and dirt every day,” she recalls, “but it was good money, and I learned to drive a forklift and a Bobcat.” 

Truth be told, construction wasn't a serious career consideration for Peterein until a college co-op broadened her perspective. She spent two semesters working at City Utilities of Springfield, a utility company serving communities in southwest Missouri. Her role involved laying out new water and gas lines as well as coordinating with contractors installing the systems in the field. 

That experience crystallized her commitment to a career that blended technical problem-solving with community building.

The Path to Precon

Following graduation in May 2000, Peterein joined another St. Louis–based general contractor as a project engineer on the company’s largest project at the time. When her civil portion of the project wrapped up, the firm enlisted her to assist the project estimator support a steady stream of developer-related estimates. 

It ended up unlocking a skillset that has defined the balance of her career. 

After signing on with McCarthy as an estimator in July 2004, Peterein immediately embarked on one of her most formidable project challenges: estimating a blast-resistant addition to a historic, block-long office building in downtown St. Louis. The construction team had to demolish an existing parking garage and infill the block with a structure so seamlessly integrated that most observers can’t tell where the original building ends and the addition begins. 

Since then, her eclectic portfolio has encompassed everything from the St. Louis Aquarium at Union Station—home to more than 250 species of fish and aquatic life—to pharmaceutical-grade clean rooms where a two-degree temperature swing can ruin million-dollar production batches.

Beyond the technical complexities of the job, it’s the collaborative relationships with her precon teammates and operational partners that keep Peterein engaged.