By Sabrina Karl

The U.S. is experiencing a significant shortage of available homes, and it’s possible the scarcity could last a decade or more.

An analysis by National Public Radio’s “Planet Money” identified three factors that on their own would have significantly impacted the number of available housing units. But combined, they are having a dramatic effect that’s likely to take years to reverse.

The first is generational. Baby boomers are staying in their homes longer than older Americans of the past. In large part it’s because they’re healthier than previous cohorts, enabling them to live independently in their homes until a more advanced age. Consequently, though they make up 28% of the adult population, they own 44% of the homes.

A second impediment to increasing housing inventory is the growing practice by homeowners of blocking new developments. Many want nothing but stand-alone single-family homes added to their neighborhoods, and they’ve gotten more active in their opposition. As a result, many cities' zoning laws now prevent the building of duplexes, three-units, etc., which will make it very difficult, if not impossible, to add as many housing units as we need.

Lastly, our shortage can be traced back to the Great Recession, when the U.S. saw a glut of homes on the market. With too much inventory, the industry pulled back on more building, essentially starting this backlog more than ten years ago. More importantly, people who might have entered the housing trades didn't, since the near-term prospects for the industry were dim. As a result, the number of skilled trades needed for homebuilding is far below what’s needed to meet current demand, and it could take ten years or more to sufficiently replenish the country’s trades capacity.

Planet Money’s “Three Reasons for the Housing Shortage” aired July 30 and can be found online.