High above the Schuylkill, in the Ridge Park section of Roxborough, old millworker houses sit side by side with wood-trimmed Victorian mansions. The little houses are jammed together as tightly as crayons in a box, but they typically sit back from the street, often behind postage-stamp gardens, and many have snug porches or high stoops. The streets, still paved in red and yellow brick, rise steeply, and thick woods carpet the slopes behind the houses. It's just 10 miles from Center City, but it might be a small town in Pennsylvania.

That village-in-the-city quality is what locals love about the quirky Philadelphia neighborhoods that hug the long ridge that follows the river. From high points like Germany Hill, Center City's skyline glistens like a distant Oz. It's not unusual to spot a deer or fox in someone's yard.

But now, the same housing boom that took Philadelphia's flatlands by storm is blowing into this quiet corner of the city, and it is threatening to turn the compact village into something more like a suburban subdivision. Developers have been clear-cutting older homes and replacing them with alien McTownhouses decked out with vinyl siding and gabled roofs. Instead of gardens and porches, the newcomers greet their neighbors with front-loaded garages and concrete parking pads.

The story in Roxborough isn't all that different from what is happening in Graduate Hospital or Fishtown, where garages are also taking over the ground floors on traditional rowhouse blocks. But Roxborough residents have found a way to fight back, and their approach could be instructive for the city's other booming neighborhoods.

With the help of the city Planning Department, they've carved out two districts - one in Central Roxborough, the other in Ridge Park - where special zoning rules apply. Known as a Neighborhood Conservation Overlay, the rules are meant to ensure that new housing reflects the neighborhood's urban values.

The goal, says city planner Matt Wysong, is to protect the area's "special character, especially its walkability," while preserving its distinctive mix of rowhouses, twins, and single-family houses.

Both overlays set standards for how far houses can be set back from the sidewalk and how much of the site can be paved. The Central Roxborough version (which covers parts of Manayunk) prohibits front-loaded garages. That provision, unfortunately, was deleted from the Ridge Park overlay by City Council, but neighbors hope to have it restored.

The demand for the controls was sparked by a spate of teardowns in Roxborough and nearby Wissahickon. Although dominated by rowhouses, these areas are studded with larger and fancier twins and single-family houses dating from the 19th century.

As developers moved in, they immediately trained their sights on the big houses because of their generous yards. A single teardown can net space for a dozen townhouses. Soon, blocks that had been an eclectic patchwork of gardens and stoops became an unrelenting Sahara of parking pads.

What really set residents off was the loss of several grand houses that were neighborhood fixtures. Three years ago, developers leveled the stone Bunting House in the Ridge Avenue shopping district for a Wendy's surrounded by a large parking lot. "We felt like we were losing all our big houses," says Kay Sykora, who worked on the Central Roxborough overlay.

In the spring, the quest for building lots got so crazy a developer even tried to slice off half of an 1880 Queen Anne-style twin in Wissahickon to make way for eight houses. Only a last-minute nomination by the Historical Commission stopped the amputation. Instead, a deal was worked out that kept the twin intact while allowing the developer to construct seven townhouses on the property.

As Sandy Sorlien, a Ridge Park activist, concedes, it wasn't just the teardowns that had neighbors in the northwest neighborhoods reeling. It was the sudden increase in density and the abrupt change in building style that set off alarms. Many wanted to stop new construction altogether.

But as the debate progressed, cooler heads prevailed. The Roxborough civic groups switched their focus to what mattered most: the form of the new houses.

"We can't fight density. It's coming. We can't dictate design standards," explains Sorlien, who helped write the overlay rules. "But we realized that we can manage the form of these houses so they fit into the neighborhood better."

They agreed the biggest threat to the neighborhood's charm was a suburban mind-set that prizes parking over everything else. The overlay restores a balance. Garages are still allowed in Central Roxborough. They just can't be in the front of the house. Single-family houses also were rezoned to allow fewer houses on the lot. That makes them less attractive as teardowns, Sykora says.

Surprisingly, even some developers welcome the new rules. Vaughan Buckley, who takes responsibility for nearly two dozen garage-fronted houses, says he's happy to see the new rules because they level the playing field.

"I'm not building front garages because I want to build them," he says. "I'm building them because I have to react to the market" and the competition. About 60 percent of the newcomers are empty-nesters from the suburbs. "They want to live in the city, but not downtown."

Because the overlays are so new, it's still too early to measure their impact. Queen Village and Overbrook introduced overlays several years ago, also as a way to protect the character of their neighborhoods. One thing is clear: They haven't slowed the frenzy of construction.

Roxborough residents have no illusions about how much they can control, Sorlien concedes. A few less sore thumbs would be nice.