Owning a home, the most common way Americans build wealth, can become a distant dream for many crushed by student debt.

Eighty-three percent of people ages 22 to 35 with student debt who haven't bought a house yet blame their educational loans.

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In the late 1990s, Ed McKinley fell in love with a $65,000 house by a lake in New Hampshire. The owners let him move in early and pay rent until the buying process was completed. Inside his new home, McKinley installed a modern stove, painted the walls and began to redo the floors. Then came the bad news. "The mortgage company decided that my income-to-debt ratio was a little bit higher than they were comfortable with," McKinley, 59, said. They were referring to his $34,000 in federal student loan debt. He had to pack up and leave. "It's crushing," McKinley said, choking up. "I have a very strong desire to own a piece of land that I can put my signature on."

Ed McKinley Source: Ed McKinley

Student loan debt has become a major barrier to homeownership in America. Some 45 million people in the United States carry student debt. Almost a fifth owe more than $100,000, according to the National Association of Realtors. People's monthly student loan payments can eat up a large slice of their income, threaten to push down their credit scores and make saving nearly impossible — all huge impediments, of course, to landing in a house. Eighty-three percent of people ages 22 to 35 with student debt who haven't bought a house yet blame their educational loans, according to the Realtors. And while 86 percent of millennials believe that buying a house is a good financial investment, only 15 percent have a mortgage today, according to information services company Experian.

"Student loan debtholders do want to own a home; that's part of their American dream," said Jessica Lautz, managing director of survey research and communication for the National Association of Realtors. "It's just really hard to get there right now." To be sure, people who receive more education also tend to earn higher incomes, possibly offsetting some of the financial distress of student loan debt, said Jonathan Spader, a senior research associate at the Joint Center for Housing Studies at Harvard University. "You have these competing influences of greater access to education versus reduced ability to buy a home because of student loan debt," Spader said.

Challenge one: Debt-to-income ratio

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Almost one-fifth of people with student debt who apply for a mortgage — like McKinley — are denied because of their "debt-to-income ratio," which is what a person owes versus how much they make, according to the Realtors. The median income for student loan borrowers is $59,746, according to analysts at the Harvard joint center. For borrowers under 30, the average monthly loan payment is $351, according to Student Loan Hero. "The bank looks at it as 'unsecured debt,'" said Doug Amis, a certified financial planner at Cardinal Retirement Planning in Cary, North Carolina. "With a mortgage, you have the asset of the house. If you stopped paying, you could foreclose on the house. "But you can't go and foreclose on an education." In other words: Banks know you'll most likely be stuck with your student debt until you pay it off. "The mortgage officer wants to see that your overall expenditures on housing and debt — including student loans and car payments — is not more than 36 percent of your income," Amis said. "That's really going to limit things if you're only making $50,000 a year." In certain areas where the cost of living is higher, that debt ceiling is pushed up.

Challenge two: Credit score

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Eight percent of student loan borrowers are denied a mortgage because of their credit score, according to the Realtors. Mike, a government worker in Yukon, Oklahoma, said banks offering loans would line up at his law school at the University of Toledo. (He asked to use his first name only because of his job with the government.) He graduated in 2008, with more than $200,000 in debt, into the Great Recession. He couldn't find a job and soon defaulted on his student loans, as 40 percent of all borrowers are expected to do by 2023, according to the Brookings Institution. He felt helpless. "I just ignored it, there was no way — they were wanting $1,200 a month," Mike said. His credit score sank into the low 500s, which is considered very poor by credit data company Experian. "If I went into any bank in Oklahoma, they would just laugh at me," Mike said.

Challenge three: Down payment