Council Acts to Preserve Estate-Size Lots : Development: An ordinance is sought to prevent potential subdivision applications in a residential area of Sherman Oaks.

A plan to prevent speculators from buying large, estate-size lots in a quiet residential area of Sherman Oaks and building two or three houses on them was given a boost Friday by the Los Angeles City Council.

By a unanimous vote, the council ordered city officials to prepare an ordinance to increase the minimum size of building lots in an area bounded by Beverly Glen Boulevard, Saugus Avenue, Valley Vista Boulevard and Greenleaf Street.

The council ordered planning officials to prepare the measure for adoption in six months.

The proposal by Councilman Zev Yaroslavsky calls for changing the area’s zoning to allow houses to be built only on lots of at least 15,000 square feet. Current zoning permits home construction on 5,000-square-foot lots.

Because many lots in the area have 20,000 square feet, they are ripe for unwelcome development under existing zoning rules, Yaroslavsky said.

But Yaroslavsky’s proposal would not prevent developers from building houses on existing lots of more than 5,000 square feet and less than 15,000 square feet, city officials said.

Yaroslavsky said his plan primarily seeks to head off a potential problem. “We want to do this before we see a rash of subdivision applications,” he said.

City Planning Department records show that only two subdivision applications have been filed during the past two years in the affected area, but Yaroslavsky and his staff say the area is ripe for such development.

A similar proposal to prevent large residential lots from being subdivided is now being reviewed for implementation in Councilman Marvin Braude’s district in Encino.