With a growing reach in Suffolk and even into other states, a local church is planning to double the size of its sanctuary to accommodate its burgeoning congregation.

Southside Baptist Church on Wednesday received authorization from City Council to add onto its current building, located at 917 Carolina Road. The church currently has three services and three Sunday school hours on Sunday mornings to accommodate all its members and guests.

“It’s just a matter of mathematics,” said Pastor Stewart McCarter. “We’re growing, and we’re already out of room. We had to go to three services because of the number of people that were coming, and three services is about our limit.”

The church’s first two services, at 8 a.m. and 9:30 a.m., have a little bit of room in them, McCarter said. However, the 11 a.m. service is “pretty crowded” most weekends, and the 9:30 a.m. Sunday school hour is bursting at the seams.

The church has had the addition in the works for about two years, McCarter said. The church is now starting to raise funds to construct the addition.

“We knew one day we’d need to expand,” McCarter said. “We’ve been planning on that for a long time.”

The decision to expand was based on the “80 percent rule.” In church work, McCarter explained, a church must have enough room for parking, education space (Sunday school) and worship space. People perceive a space as full at 80 percent, so a church will only grow to 80 percent of its smallest space. For example, if a church has 100 parking spaces, and each car brings two people, the church will only grow to roughly 160 people (80 percent of 200), even if there is a 500-seat auditorium.

“We’ve tried to balance out those three areas — education, worship and parking — as we’ve grown,” McCarter said.

McCarter hopes adding more space will allow the church to grow in size, and in its members’ relationships with the Lord.

“Just increasing your [space] isn’t going to bring people in or keep them there, but if you don’t have room for them, they might come once or twice” but then will not return, McCarter said.

McCarter compared the church’s expansion to the Biblical story of a widow who was running out of oil, and a prophet instructed her to go find as many containers as she could.

“As long as she had containers, the oil kept flowing,” McCarter said. “She filled up every container they provided.”

In addition to filling its main container, Southside Baptist also is reaching beyond its property line. Not only does the church give 10 percent of all money that comes in to missions, but its members have supported four church plants across three states in recent years.

The first, Abundant Hope in Gates County, N.C., was started by the church’s former youth pastor. The church has reached 120 people, bought land and constructed a building.

“They’re still growing,” McCarter said.

The second, in Franklin, is called River of Life. Another, in Baltimore, Md., was started by the youth director’s daughter and her husband.

The church also supports a plant right here in Suffolk. The church plant, officially called the “North Suffolk Mission,” is often referred to as the “Ugly Mug Church,” since it meets at the Ugly Mug coffee shop on Godwin Boulevard.

McCarter said the church is growing inside because it focuses on the outside.

“It’s not just about just us,” McCarter said. “People are open and friendly and have something to come to. We give them a positive message.”