WESTBROOK – While the outside of the building still looks much the same, work is rapidly progressing to transform the interior of the former Warren Memorial Library on Main Street into the new regional headquarters of the Northern New England Conference of the Seventh Day Adventist Church.

During a tour of the building earlier this week, Caleb Johnson, the Biddeford-based architect and builder who has been hired to renovate the building for the church, said he was pleased with the progress, which started about two months ago and should be completed in January.

“It’s been very easy,” Johnson said. “(The church was originally) considering a much more extensive project up (at Pine Tree Academy) in Freeport. That was going to be a multi-million dollar project, years long, and then the treasurer of the church found out about this building. The building is a perfect match for what they want to do and it’s a really high quality building, really well maintained.”

The church has big plans for the former library, which include a museum chronicling the history of Christianity of all denominations, a new headquarters for the church’s northern New England branch and services in the building’s 4,500-square-foot auditorium.

The church closed in October 2011 on the former Warren Memorial Library, buying the 479 Main St. building for $900,000. The price was considered a bargain, considering the building initially went on the market in early 2010 for $1.195 million.

Johnson said this week that he estimated the total cost of the renovations to the building would come in at “less than $500,000.” Johnson added that when he compared the church’s original plans for a new building in Freeport with what it could do with the existing building, he told church administration that they were getting a higher-quality building at a quarter of the cost.

“It’s an ideal building,” he said.

The building originally served as a private library for the city for more than 130 years, beginning as a library for employees of the S.D. Warren paper mill. In 1929, the Warren Memorial Foundation was established to support education and the arts.

The foundation, which also supported the 14,500-square-foot library, decided to close it in 2009, despite the fact that it had recently spent $2.5 million to renovate the building. Board members at the time said that because of the economic downturn, the foundation would deplete its endowment if it kept the library open.

The fact that the building had just undergone an extensive renovation made the transformation into church offices fairly easy, Johnson said.

“They (the Warren Foundation) did a quality job,” he said. “They didn’t spare expenses.”

Johnson said the Warren Foundation “really left the building in great shape,” and that made it easy for the church to save money on the renovations.

“We made the decision, ‘Let’s not waste the church’s money and give the whole building a makeover, let’s just take cues from the last renovation and stick with that,” he said.

Johnson said that instead of doing a complete rebuild inside, the church is creating office spaces with sheetrock and glass walls and leaving most of the rest of the interior alone. “The building has great bones for what they want to do,” Johnson said.

The city receives no taxes for the building because the church is tax-exempt.

The Seventh Day Adventists practice a Protestant Christian faith that the Northern New England Conference president, Mike Ortel, described in an interview last year as “middle of the road.” The church, which was founded in the Portland area in 1863, adheres to the Bible, perhaps more strictly than more liberal-leaning divisions like the Unitarian Universalists, but, Ortel said, the church is not as strict as other Christian fundamentalist faiths. Like the Jewish faith, Ortel said, the Seventh Day Adventists also consider Saturday, not Sunday, the holy day of the week, and hold services then. The church also believes in living a healthy lifestyle. Ortel said congregants don’t drink, smoke, or use drugs and many are vegetarians.

The Northern New England Conference covers Maine, New Hampshire and Vermont, and has a total of 5,200 members throughout that area. In all, the conference oversees 60 churches, 12 elementary schools, and two high schools spread out over all three states. In addition, the conference maintains a 200-acre seasonal campground in Weld, a 54-site campground in Freeport, a 48-unit 55-plus senior housing complex in Brunswick, and the Parkview Adventist Medical Center in Brunswick.

Builder and architect Caleb Johnson, left, speaks with framing contractor Jason Rickett as work continues on the interior of the former Warren Memorial Library building on Main Street. The Northern New England Conference of the Seventh Day Adventist Church is converting the former library into its new regional headquarters.