SUNDERLAND — In December 1989, one of the coldest on record in the region, John Sackrey was in Conway with a small team building an addition onto a home.

That addition, for an associate working with Berkshire Design Group, kicked off a decades-long legacy of design and construction work. That day marked the birth of Sackrey Construction Co., which is celebrating 35 years of business on Friday, Dec. 13.

“That was the first job and we’ve never stopped,” Sackrey said in his office.

Sackrey and his team of six employees have undertaken countless residential projects around the Pioneer Valley since he started his business, which was initially operated out of his Westhampton home. He’s also completed several commercial projects, including the Whalen Insurance building in Northampton and the former Sinauer Associates building in Sunderland.

He described the company’s work process as “frame to finish,” as Sackrey Construction used to do more design work but has shifted to mostly construction in recent years.

While the construction industry has evolved in many ways since Sackrey started his company, such as the addition of cellphones, new excavation technology and the introduction of net-zero homes, he said many things remain the same. He pointed to the spreadsheet format he’s used for decades, which he originally laid out on IBM’s long-discontinued Lotus 1-2-3 program.

“The industry’s changed, I’m not sure I have. … I’ve been using the same spreadsheet forever, I’m embarrassed to say,” he said. The biggest change, Sackrey noted, is the use of cellphones, which have made it easier to administer jobs because he can easily reach subcontractors and schedule deliveries.

While technology has changed, the key to maintaining a successful family-run business, especially in construction, has not, Sackrey said. Consistency and relationship-building with customers, subcontractors and vendors are essential.

“You have to trust each other to build,” he said, noting that building residential homes creates a special relationship, as someone is trusting you to build the place where they will live. “You really become friends.”

As the company celebrates its milestone this weekend, John Sackrey said his wife, Traci, has been “instrumental” to his success over the years, as she has handled marketing and communications for the company, as well as some interior design work. His three kids, too, have been involved in small ways, as they used to help with small tasks when they were younger and one of his sons still works summers with him.

While Sackrey, 66, has three and a half decades of work under his belt, he said there’s still plenty of work to be done here in the Pioneer Valley. He said he envisions working maybe five more years, which would be enough time to see his kids through college.

“I think I’m gonna keep rolling for a while,” he said, joking that he’s a classic example of a self-employed person who would struggle to find something to do in retirement, but when the time does come, he hopes Sackrey Construction will live on. “I would like to see the business continued with one of my employees if somebody’s interested, or one of my kids if they’re interested at that point.”

For more information about Sackrey Construction, visit sackreyconstruction.com.

Chris Larabee can be reached at clarabee@recorder.com.