Formula to Subtract From the Multiplication of Hillside Homes

Developers hoping to build houses in rugged Topanga Canyon may soon discover that a mathematician is as important to their projects as an architect, a geologist or a slope engineer.

Los Angeles County officials have unveiled a complicated formula that they plan to use to determine how large houses can be in a mountainous area.

County planners are reacting to canyon dwellers’ complaints that oversized homes are being built on tiny hillside cabin lots left over from 1920s-era subdivisions. Besides giving the rural canyon a crowded look, the flurry of construction is overtaxing the community’s schools and streets and is causing septic system problems, residents say.

The proposed formula would control the size of new homes through an equation that involves the average slope of the construction site.

In the formula, GSA is the allowable floor space, A is the area of the building site and S is the slope, which is calculated separately. On paper, the formula reads like this:

GSA = (A/5) x ((50-S)/35) + 500

Robert Hoie, a supervisor with the county Planning Department’s Ordinance Studies Division, told 170 people attending a Topanga Town Council meeting Thursday night that the formula could make developers combine several small lots to build a large house.

“Someone building a 2,000-square-foot house would have to do it on several lots,” he said.

Hearings Planned

Hoie said the county’s Regional Planning Commission will hold hearings on the small-lot restriction proposal before county supervisors are asked to approve it. In the meantime, he urged canyon residents and landowners to study the formula and consider its ramifications.

Barry Glaser, president of the Town Council, said members of his group will meet next month to discuss the proposal.

Glaser said the small-lot formula would be the second crackdown by the county on canyon overdevelopment. The county already has inspectors watching for illegal grading and construction Saturdays and Sundays, he told residents.

Town Council leaders and others in the canyon called for tougher rules after a builder constructed five out-of-scale houses on small hillside lots along Medley Lane, a curving street perched high above the canyon.

Robert Boucher, president of the Topanga Homeowners Assn., said neighbors feared that the developer was planning to build 47 similar homes on other small parcels along the lane.

“It’s totally out of character with this rural community,” said Katie Phillips, an artist who lives below the Medley Lane homes and helped organize opposition to them.

Several of those at Thursday’s meeting voiced concern that enforcement of the new rules--particularly by weekend inspectors--could turn neighbor against neighbor.

But most told Hoie that they are worried that there will not be enough enforcement to keep development in check.

In the past, county building inspectors have allowed developers to do such things as place septic tank percolation pits in stream beds, said homeowner Don Barceloux.

“Developers have to know that when the man behind the desk says ‘no,’ it means something,” resident Barry Leneman said.

Hoie said the new restrictions may not be foolproof.

“I’m not going to stand here and say that if a guy gets a permit for a house that’s 1,132 square feet, but builds 1,527 square feet, that there’s going to be a force of will for the county to go out and bulldoze it,” he said.