When Murphy Jr. met Whiteman two decades ago, they were fast friends. Whiteman had sold his own construction company. He was working on a Ph.D. at the University of Florida and taught Thomas C. Murphy, the CEO’s son, in an undergraduate class. Whiteman joined Coastal in 1997 after serving as an advisor and became president after 18 months.

When Murphy Jr. decided to grow the business, he hired consultants to analyze its culture and operations. Over time, Coastal formalized practices and procedures. The company strives to keep up on technology and to provide training for employees, he said.

“They have continuing education to keep all employees updated. They’ve got a good operation going,’’ said Neil Levy, an assistant project manager, who is among the laid-off employees recently rehired.

Murphy Jr. said a painful aspect of expanding the firm was jettisoning employees who didn’t buy in to the more corporate environment. “Those are the people you have to let go, because they’ll stall you,’’ he said.

He has been equally tough-minded about his own relatives. Eleven family members work in the business, but others have gotten the boot. “I had to let three go,’’ said Murphy, Jr.

“You have to have passion in the belly. If they’re looking at their watch, they’re not going to make it around here,’’ he said.

He coaches his sons to work harder than other employees to combat any perception of nepotism. “Even if you work every day without a break for a year, if you take a week off, people are going to say ‘You know who his dad is,’ ’’ Murphy Jr. said.

Murphy Jr., who credits his father for his values, preaches some basic principles — echoed repeatedly by his top lieutenants during interviews. They are tenets that apply to most any business.

The foremost is putting people first. “Respect people,’’ said Sean Murphy, 41, executive vice president of operations and the second of three sons. “Don’t think you know everything. Settle down and listen.’’

“I could be talking to a billionaire, and an hour later I’ll be talking to a laborer. You have to be able to deal with people at all different levels,’’ Sean Murphy said. “Treat people with respect. We want to earn a good fee, but we service the crap out of things to service the client.’’

Developer Gil Dezer, who has tapped Coastal for the Porsche Design Tower, a luxury condominium planned for Sunny Isles Beach, said: “These are true gentlemen to do business with, which is very unusual in the construction business. I look forward to doing business with them again.’’

“I’m doing my third building with them,’’ said Alan Ojeda, president of the Rilea Group, which hired the firm as general contractor for the Monte Carlo rental-apartment project in Miami Beach. “They are good people.’’

Coastal executives often talk about focusing on long-term relationships and guarding reputation.

“We’re in the business of building, but we’re really in the business of building relationships,’’ said Mike Murphy, a cousin of Murphy Jr. and vice president of quality assurance overseeing the post-construction warranty business. “Today I was at three projects. If you can catch something early, you can be proactive, not reactive,’’ he said.

Another common theme at Coastal: You can’t make a good deal with a bad client. Even in the downturn, Coastal wouldn’t take jobs that looked potentially troublesome.

“We interview people a lot tougher than they interview us,’’ said Murphy Jr.

“One bad job, one bad client can put you out of business,’’ said Sean Murphy.

Coastal boasts that 85 percent of its work comes from repeat business.

“We’ve never been to court with a client — and we’re in the nastiest business there is,’’ said Murphy Jr. “I’d rather take a hit to profits and save our reputation.’’