Builders looking to meet the needs of homebuyers should start looking below ground level when constructing new homes, according to the National Association of Home Builders.

According to the “What 21st Century Home Buyers Want” survey of customer preferences conducted by the NAHB, the inclusion of basements in new homes has been on an upward rise since 2000. Homes being built on slabs are declining, as homeowners find more value in basements both during their occupancy of the home and at the time of resale.

“There’s nothing like a well-insulated basement that can serve as valuable living space to pop the eyes open of a potential homebuyer,” says Atlanta Realton Tina Fountain. “You can see the wheels start turning in a homebuyer’s mind as they quickly calculate what they can do with the ‘bonus space.’ A good basement takes the pressure off the other living areas in the home and opens up a world of possibilities for potential homebuyers.”

The survey says married couples with children and high-income households generally look for full basements.