They’re Growing Older. Their Mortgage Debt Is Growing Deeper.

It was a modest house, a two-bedroom ranch in Arlington, Mass. Jerri and Richard Newman had to stretch to buy it for $169,000 in 1996, but with his job at Boston’s Museum of Fine Arts and her freelance editing, they figured they could swing it.

They took out a 30-year, fixed-rate mortgage. But their son developed mental health disabilities, including a bipolar disorder. To pay for his care, and help compensate for Ms. Newman’s interrupted career, the Newmans refinanced four times and took out a home-equity loan.

In an earlier era, the Newmans — he’s 65; she’s 62 — might now be contemplating retirement in a paid-for home. Instead, they’ve amassed so much mortgage debt, about $375,000, that they’re reluctantly considering selling. “We tried for years to catch up,” Ms. Newman said.

“The norm for a long time was, if you bought a house at 35 and didn’t refinance, you’d be done paying for it by retirement,” said Geoffrey Sanzenbacher, a research economist at the Center for Retirement Research at Boston College.

Amid the continuing fallout from the housing boom and bust, however, a growing proportion of older homeowners now carries mortgage debt. And the average amount keeps rising, according to two recent studies, which may portend lower standards of living for many retirees.

More than three-quarters of Americans over 65 remain homeowners despite housing market gyrations. Those houses usually represent their greatest single asset.

But often there’s little equity left, even as prices have largely recovered, because so many older homeowners have borrowed against their homes.

As housing values rose more than 60 percent nationally between 2000 and 2006, homeowners like the Newmans (more than younger ones) refinanced and took out cash, or signed up for home equity loans or lines of credit.

The proportion of homeowners over 55 with housing debt has climbed, the Boston College group recently reported. Dr. Sanzenbacher provided the numbers: 50 percent still had mortgages, home equity loans or lines of credit in 2013, compared with 38 percent in 1998.

An Urban Institute study published this month, based on data from the national Health and Retirement Study, found a similar pattern among homeowners over 65. The proportion with housing debt rose to 35 percent in 2012 from 23.9 percent in 1998.

Moreover, the median amount they owed nearly doubled, to $82,000 from $44,000.

Tapping home equity “was an attractive opportunity,” Dr. Sanzenbacher said. “If you assumed housing prices would keep going up, it didn’t seem very risky.”

At the same time, cultural attitudes about owing money shifted, said Barbara Butrica, an economist and co-author of the Urban Institute report. “It used to be a stigma to have debt,” she said. “Now everyone has debt.”

Let’s not overlook the role of banks and other lenders, either. “Financial institutions were very opportunistic,” Dr. Butrica said. “They made it easy to refinance or take out a home-equity loan or line of credit.”

Housing prices didn’t keep rising, of course. After they plummeted, would-be retirees confronted the prospect of years during which salaries would stop, but monthly mortgage payments wouldn’t.

Some of these households face a precarious financial future. In 1998, less than 3 percent of homeowners over 65 were “underwater,” with housing debt that exceeded the value of their homes, the Urban Institute analysis found. By 2012, that proportion topped 8 percent.

The institute also looked at older homeowners with loan-to-value ratios of 80 percent or more, meaning that their debts had reached 80 percent of their home values, often a point at which banks won’t approve loans, charge higher interest rates or require mortgage insurance.

In 1998, 8.4 percent of older homeowners had reached an 80 percent ratio. In 2012, 19.5 percent had. “If you think of 80 percent as the threshold for being at risk of default, it’s pretty dramatic,” Dr. Butrica said.

Her study also found that health events or work-limiting conditions, like those the Newmans experienced, correlate with higher rates of home equity borrowing.

Housing debt can have the greatest impact on the middle class, Dr. Sanzenbacher said. Lower-income retirees are less likely to own homes, and the wealthy rely less on home equity.

But for most retirees, even if they don’t tap their equity initially, a paid-for house represents security. They can live rent free (though, of course, they still pay property taxes, utilities and maintenance), or they can sell the house to finance a move to a retirement community or a nursing home.

Dr. Sanzenbacher and his colleagues calculate a National Retirement Risk Index, which indicates how many working-age households may be unable to sustain their standards of living after they stop working.

It’s always a scary number: 30 percent in 1989, rising into the 40 percent range during the boom and bust. In 2013, given longer life expectancies, historically low interest rates and lower home equity, the figure reached 52 percent.

What’s unclear, economists say, is whether this debt crunch will turn out to be a one-time phenomenon. Is it a consequence of an imploding housing market that will not recur, or an ongoing reality that now must be factored into most Americans’ retirement planning?

Dr. Butrica votes for the latter. The rise in housing debt predated the recession, she pointed out. Even if that debt levels off, as recent data suggest, she doesn’t see it going away.

Her work has shown that older people with mortgage debt tend to stay in the labor force longer, and to delay receiving Social Security benefits.

The Newmans are likely to be among them. Mr. Newman intends to stay in his job as long as possible; he likes his work and also hopes to rebuild his employee retirement savings. “We’re in better shape than a lot of people,” he said.

That’s particularly true for black and Hispanic homeowners and those with high school diplomas. They’re more apt to be overextended, at the 80 percent loan-to-value mark, than whites, the college educated or upper-income households.

The Newmans, living frugally and trying everything from a mortgage modification (they didn’t qualify) to an interest-only arrangement (it helped, but lasted only two years) remain stuck with an 8 percent mortgage, twice the rate many local lenders offer. But they don’t want to default.

“The solution would be refinancing at a reasonable rate,” Mr. Newman said. “But because of our history and our credit rating, we don’t qualify.”

Selling their house would allow them to settle their obligations, but it’s not clear where they and their son would live.

They have the very minor consolation of knowing that their situation is no longer unusual.

“We need to recognize that people are retiring with a monthly payment that previous generations didn’t have,” Dr. Butrica said. “And for a lot of people, it’s a pretty large payment.”