It can be built without any special zoning approval or state licenses, Mr. Levine said.

He said they also build on sites that do not require special zoning approvals or permits.

In the suburbs, such zoning plans are normally mandatory and the builders usually must construct the lower-income units on the site if they are to receive zoning approvals.

Michael Zaccaro, Carematrix executive vice president of operations, said those projects were all in the zoning, prezoning, approval and preapproval phases.

Also attractive, Mr. Naftali said, was the ability to convert and expand the building without any special zoning approvals.

Plans for the project will require zoning approval, according to Arnold Moss, president of Hudson Heritage.

Mr. Esikoff obtained the necessary zoning approvals in 1981, but was unable to proceed because of high interest rates and a general slump in the residential market.

Indeed, Dr. Rothberg sought no zoning approval or building permit because, he said, "my position is, if I put up a piece of art, I don't need permission."

A lawsuit filed by a resident challenging zoning approvals for the warehouse is currently pending.

The plan needs no special zoning approvals, and participants expect a groundbreaking next year.