• Owner: Michael Tronstad

• Location: 973 Enterprise Way, 224-6527

• Years in business: 69

When George Slinsen started Slinsen Construction in 1938 all that was necessary to seal a business deal was a handshake. “He started the business when I was 1 year old,” said his daughter Betty Tronstad.

Slinsen Construction specializes in paving — everything from streets and driveways to tennis courts.

The business was first located on Silverado Trail at the family’s home. From there it moved to Trancas Street, where it was located for 20 years. The land is now occupied by Longs Drug, across the street from the Sizzler Restaurant. From there the construction business moved to McKinstry Street across from the Wine Train station. Today it is on Enterprise Way.

According to Betty Tronstad, in the 1960s Slinsen Construction Co. was the largest paving company in Napa County.

One of the early big jobs in Napa was the East Side Reservoir in Alta Heights, which has since been filled in and developed as a park.

Slinsen paved Napa’s first overpass — Old Sonoma Road that rises over Highway 29. The paving company also paved the parking lots for many of the public schools in Napa and numerous wineries that were getting started in the valley in the 1960s.

Slinsen also paved the parking areas and did vineyard grading at Robert Mondavi Winery in Oakville and the driveway and tennis court at his home, according to Tronstad.

Slinsen Construction also did grading and paving work at Domaine Chandon in Yountville and Trefethen Winery, north of Napa and did grading at Silverado Resort and Kennedy golf courses.

Slinsen, who was born on Mount Veeder, died in 1979. Betty Tronstad’s husband Ken Tronstad was hired by her dad in 1957 as a laborer and he worked his way up.

“So when Dad died we bought the company from my mother and my husband ran it until he retired 14 years ago.

“When (Ken) retired we sold to his brother Larry Tronstad, who turned over the reins three years ago and sold the paving business to his son Michael Tronstad who is operating the company today. And that is where we are today,” said Betty Tronstad.

What is Slinsen Construction’s secret to longevity?

“My dad was an honest businessman ... and that hasn’t changed and they do good quality work,” Betty Tronstad said, adding that there are streets in Napa that they paved in the 1950s and ’60s that are holding up better than some of the newer ones dotted pot holes.

“My father would be proud to see the business carried on the way it has,” Betty Tronstad said.

Michael Tronstad said plans to expand business are on the back burner right now. “But there has been a thought to expand.”

In the 1960s Slinsen was one of the largest paving and grading companies in the valley, but today is one of the smaller ones, according to Michael Tronstad.

The business started with a 1928 Caterpillar tractor and at its peaked included 56 pieces of equipment.

And today the business is one of the smaller union companies in the valley.

Slinsen, which has one part-time and 10 full-time employees, prides itself on being able to retain good workers.

Michael Tronstad, 34, said there is one worker who has been with them for 40 years — and still works part time — while there are about four others with at least 20 years with the business.

Michael Tronstad’s assessment of why the company continues to thrive is “the guys are proud of what they do. The quality of work makes them feel good. They get compliments and they take those to heart; it makes them feel good with their work.”

Michael Tronstad estimates 90 percent of the business is in Napa County, with the remainder in Sonoma and Solano counties.