English basements are common in urban centers, allowing homeowners to maximize their basement space by renting it out to tenants or providing an extra living space for family or friends.

English basements emerged out of 19th century London, allowing people to comfortably live below row houses, which are low-rise buildings that share a common wall on one or both sides.

In the U.S., the English basement can be found anywhere with row houses, sharing a few common characteristics: small windows, better ventilation than its predecessor and accessibility from the outside, according to a Bloomberg report.

English basements in the U.S. can usually be found in big cities with brownstones or townhouses, such as in Philadelphia, Baltimore, Chicago and New York City, but are more commonly found in the District of Columbia, particularly in older homes.

English basements occupy the lowest floor of row houses, sitting partially below ground with smaller windows at street level. There’s also a separate entrance to the unit from the rest of the building.

“They're usually smaller,” Minshall says. “A lot of times they're in basements so they can be dark.”

Pros – English basements can provide an extra living space for family or friends. – It can provide rental income for homeowners. – The separate entrance provides some privacy as the occupant doesn’t have to go through the main living area of the home. – Basement units can be more affordable.

The cost to turn a basement into an apartment ranges between $50,000 to $100,000. In some high-cost living areas, you could pay $150,000 or more, according to HomeAdvisor.