San Francisco ? For most of the past 37 years, the dinner dress code was coats and ties for men, skirts or dresses for women, at The Sequoias, a high-rise retirement community. But the newer, younger residents lobbied successfully for more casual dining.

More than two years later, some of the old-timers are still grumbling.

“There is a definite generation gap between the ones who have lived here 20 years” and more recent arrivals, said 82-year-old Hilde Orloff.

At retirement communities around the country, a rift has opened up between the 90-year-olds and the comparatively spry 70-year-olds, between the generation that came of age during the Depression and the one that reached adulthood amid postwar prosperity.

They are clashing over such things as dress codes, the food, the conversion of tea rooms into coffee bars, and higher monthly fees to pay for the weight rooms, roomier quarters and computer-ready apartments demanded by the younger, more active set.

Maria Dwight, a Santa Monica-based consultant who helps plan and market senior-citizen housing, said older residents do not want to pay for perks they won’t use, and they can be resistant to change.

“They don’t see the facilities with fresh eyes,” she said. “So the carpet is a little worn, so what? They are living there; they are comfortable.”

The intergenerational tension is expected to mount as more and more baby boomers enter their golden years, during which they are expected to be healthier and more active than the generation that came before them. By 2030, one in five U.S. residents is expected to be 65 and older.

“This creates a real dilemma for older retirement communities,” Dwight said, “because they tend to have small dwelling units and huge dining rooms that aren’t attractive to younger older people who want weight rooms and casual dining and lap pools and a home office and room for the grandchildren to come visit.”

But even small switches, such as replacing a calisthenics class with pilates, can be disconcerting to the old-timers. At Oakmont Village, a 3,000-home neighborhood in Santa Rosa, it was the cost of spiffing up the gym that raised people’s blood pressure. At the San Francisco Towers, a luxury retirement community, there was some tension when the ladies’ tea room was transformed into a casual cafe.

Residents Betty Cable, from left, Inge Berliner and Doris Bebb, dine at San Francisco Towers retirement community in San Francisco. As residences designed for a generation that came of age during the Great Depression make way for one that entered adulthood amid postwar prosperity, more and more retirement communities are experiencing culture clashes.

One retirement-home chief executive in New Jersey was forced out after residents rebelled over plans to modernize the place, Dwight said. “They tried telling me that having an indoor lap pool was very hedonistic,” she recalled.

That is the quandary in which Northern California Presbyterian Homes and Services, which owns The Sequoias and six other retirement communities, finds itself. Chief Executive Barbara Hood said upgrading aging facilities is critical to nonprofit organizations like hers as more private developers get into the increasingly lucrative senior-citizen housing market.

The Sequoias, whose 333 residents range in age from 69 to 103, added a buffet and casual-dress seating, though it also kept sit-down table service and the dress-up rule for those who preferred it. A cafe where people can grab an espresso and pastry is also planned. And an outdoor garden for meditating and practicing tai chi was added.

“It’s their home, so of course they are going to be concerned,” Hood said of the grumbling from the older residents. But “we have to make sure we are keeping our commitments to current residents and attracting the next cohort of seniors.”

While there has been a lot of talk about what the baby boom generation will want when it retires, the changes under way have largely been targeted at their predecessors, the so-called Silent Generation born between 1925 and 1942. And they tend to be wealthier and more outspoken than the GI Generation that came before them, said Anne Burns Johnson, president of Aging Services of California.

Most senior citizens tend to adapt if the changes are handled with sensitivity, said Dee Ann Campbell, vice president of the Episcopal Homes Foundation, which operates the San Francisco Towers.

“The people who have been there a while and only did water aerobics or chair yoga will say, ‘I didn’t think I would like line dancing, but it’s really fun,” she said.

Over at The Sequoias, the chronic complainers still gripe about how things just haven’t been the same since the dining room relaxed the dress code. But many residents have embraced the buffet or learned to adapt.

“We have grandchildren coming in who wear nothing but jeans,” Orloff said, “but by and large the nasty looks have disappeared – sort of.”