When she entered Boston-based construction heavyweight Suffolk’s eight-week Trades Partnership Series program in 2015, Janet Peguero was only vaguely aware what “post-construction cleaning” meant.

Three years later, Peguero, president and owner of All Time Service Inc., a janitorial company she founded in Roslindale in 1996, has expanded her company, hired an extra 35 workers and worked on the some of the most high-profile development projects in downtown Boston. Her firm works as a Suffolk subcontractor that cleans newly built commercial and multifamily buildings from top to bottom before new tenants move in.

“I had heard about it, but didn’t know exactly what it was,” she said. “It’s the best thing I’ve done in years.”

Suffolk Construction next month launches its eighth annual Trades Partnership Series, a program designed to identify, train and help union and non-union minority, women- and veteran-owned companies become potential partners with Suffolk on construction projects as subcontractors.

The program is partly the result of a genuine desire to help diversify the trades industry by hiring minority-, women- and veteran-run firms as subcontractors, said Brooke Woodson, director of trade partner diversity at Suffolk Construction, the region’s largest construction company. But it’s also the result of Suffolk meeting legal requirements to use minority-, women- and veteran-owned firms on certain projects, such as Wynn Resorts’ $2.4 billion new casino in Everett and government-backed construction projects.

The program – which counts the city of Boston, the state of Massachusetts and the Massachusetts Minority Contractors Association as partners – accepts trade firms in the position to “take the next step” in its growth from a small firm to medium-sized or potentially larger, Woodson said. There’s no set revenue level that firms must meet to qualify for the program, but they also can’t be small “mom-and-pop” firms that aren’t in the position to take on potentially big jobs, Woodson said.

If accepted into the annual program, firm owners must attend eight two-hour classes held weekly over two months. The class topics include risk management and safety, estimating and purchasing, project management and finances, project management technology, union relationships, certification programs and other subjects.

After the courses are complete, firm owners are awarded certificates and assigned to a Suffolk “mentor,” usually a Suffolk executive who acts as a sort of consultant and advisor to company owners on exactly how to win and manage a subcontractor gig with Suffolk.

“To me, the mentoring is probably the best part of the program,” said Woodson, noting it allows small-firm owners to get to know Suffolk executives on both a professional and personal level.

Peguero, an immigrant from the Dominican Republic, agrees that the mentoring aspect of the program was a huge plus, allowing her to get to know more about how Suffolk works and what’s expected of its subcontractors.

But she said the courses also are key. Among other things, she learned how to estimate the costs and the time involved in tackling large post-construction cleaning projects.

Growth Opportunity

Before becoming a Suffolk contractor, Peguero’s firm exclusively handled the cleaning, usually at night, at existing commercial and multifamily facilities. But it was “nothing on the scale” of cleaning newly constructed office, retail and residential towers of the sawdust, glue, paints and general grime that accumulates during construction projects, she said.

“We’re referred to as the ‘last trade in,’” she said. “After all the other trades are finished, we go into the buildings to make them presentable, from top to bottom.”

Not all graduates of the Suffolk program become regular Suffolk subcontractors.

Abraham Gonzalez, owner of One Way Development in Boston, said he went through the Suffolk program in 2012 but came to the conclusion that he didn’t want to be a subcontractor for anyone. Today, his firm is a general contractor that also handles general mechanical and electrical work.

Gonzalez, a member of the Massachusetts Minority Contractors Association, said the program paid off.

“I learned so much, especially about all the (government) certification programs out there,” he said. “It was invaluable.”

Other major construction companies do try to reach out to those in the minority community in search of qualified subcontractors, said Beverly Johnson, president of the Massachusetts Minority Contractors Association, but nothing comes close to Suffolk Construction’s Trades Partnership Series.

“They definitely stand out,” she said. “Their program has become a model for others to emulate. I just can’t say enough how aggressive they’ve been (in reaching out to) minority firms. They’re committed to helping minority contractors develop the expertise they need to grow.”