I'm in the basement.

Of a bank.

Nicknamed "The Playground."

Looking at the place where Wells Fargo & Co. (WFC) tests out design ideas for a new branch concept meant for smaller spaces.

That playground turned into a physical reality for Wells Fargo customers in Washington, D.C. on Monday. Instead of teller windows, five bank employees equipped with Microsoft Surface tablets stroll around to help customers accomplish their financial tasks in Wells' new "neighborhood store."

This new, mini-branch is how the fourth-largest bank by assets thinks about adding a physical presence in an urban area during a time when people are increasingly using digital channels to do their banking. In short: the San Francisco bank is finding ways to maximize a smaller space.

Indeed, when you enter the Wells Fargo branch prototype, what strikes you first is the size: At about 1,000 square feet, the neighborhood store is less than half the size of a typical Wells Fargo brick-and-mortar location, about 3,000 to 4,000 square feet.

"We are using the space more effectively," Jonathan Velline, head of Wells Fargo ATM Banking and Store Strategy, tells BTN.

To that end, 90% of the neighborhood store is open to consumers, while only about 40% to 50% of traditional store space is accessible to customers, says Velline.

Helping the bank more easily move into a smaller space are changes in technology made over the years that have let the bank migrate away from the use of physical paper. The ability to accept digital images of checks is one example.

One unique feature of the new branch design is yellow-painted walls that open and close. The walls, which are located behind the ATMs, open during business hours to reveal somewhat private rooms available to patrons. During off hours, the movable walls are designed to close so that the space can masquerade as a standard 24-hour ATM vestibule.

There are no teller windows. The customer experience looks something like this: As a customer enters a neighborhood store, an employee equipped with a tablet will greet him and guide him to one of three ATM kiosks or a private room with a workstation, depending on the complexity of the customer's needs.

The ATMs, which come with larger screens, allow retail customers to take care of various banking needs, including dispensing $1, $5, $100 and $20 bills. The ATMs' software interface — like at Wells' other locations — anticipates a person's preferred transactions and allows the customer to get instant-issue debit cards and electronic receipts.

Wells worked with NCR Corp. to integrate self-service into the branch experience.

The D.C. neighborhood store is the only planned location for now. "It's a great way to test the market," says Velline.

"Wells Fargo stores play an important role in how we deliver services to customers," he says. "The neighborhood store is one format in a mix of formats."

As justifying the cost of physical branches becomes increasingly challenging in a digital world, other banks are also experimenting with smaller footprints, including JPMorgan Chase (JPM).