Data Foundry Inc. may be finished with its 27,000-square-foot expansion at the company's data center in North Houston, but it's by no means finished growing at the site.

The Austin company's 18-acre, master-planned campus at 660 Greens Pkwy. allows for another 200,000 square feet. At build-out, Data Foundry will operate 350,000 square feet of space there.

Currently, the data center encompasses 150,000 square feet. The recent expansion completes the development's first phase. Each of two future phases will add 100,000 square feet.

So far, there's no timetable for the data center's second and third phases.

"It's all a function of demand. We will deploy the capital in response to the pace at which we end up filling up the new space," says Ed Henigin, chief technology officer of Data Foundry.

The 27,000-square-foot expansion debuted in late January at Data Foundry's Houston 2 Data Center. Henigin says space remains available there, but the company does have prospective tenants in the pipeline. It could take anywhere from six months to four years to lease the entire expansion, he says.

Data Foundry says increased customer demand along with business growth in Houston — especially in the healthcare, energy, and manufacturing sectors — prompted the four-megawatt expansion.

"For folks who are outside of Houston, it's an underappreciated market," Henigin says. "It's a huge economy, and there's a lot of dynamic activity happening in Houston and a lot of growth."

Generally, demand for data center space in Houston is "steady and healthy," Henigin adds.

"I don't think we're really overserved or underserved at this point. I think we're pretty well-balanced," he says.

Henigin points out that demand can shift depending on the region's economic conditions, such as upswings or downturns in the energy sector.

"A lot of the folks who have businesses in Houston have learned to be a little cautious, because you don't necessarily know when the next dry spell is coming," he says. "So there's a lot of careful planning or careful execution in business practices in order to be resilient."

Although Houston ranks as the fifth largest metro area in the U.S., it's not among the country's 10 biggest data center markets, unlike Dallas-Fort Worth and Austin/San Antonio. According to DataCenterMap.com, 40 data centers operate in the Houston area. A number of the region's data centers are in North Houston, The Woodlands, and Katy, according to datacenterHawk.

Among Data Foundry's competitors in the Houston market are CyrusOne Inc., Skybox Datacenters LLC, and Stream Data Centers LP — all based in Dallas — and San Francisco-based Digital Realty Trust Inc., according to datacenterHawk.

Customers of Data Foundry's Houston 2 Data Center include Carrizo Oil & Gas Inc., FMC Technologies Inc., Marathon Oil Corp., and Mattress Firm Inc. — all based in Houston — and Galveston-based Moody National Bank.

Houston 2 offers a 185 mph wind-rated infrastructure and an elevation above the 500-year floodplain. During Hurricane Harvey, tenants didn't lose power or network service, or experience flooding, Data Foundry says.

Data Foundry has operated data centers in the Houston area since 2002. Its other Houston data center, inside the Marathon Oil Tower at 5555 San Felipe St., comprises 20,000 square feet.