Redevelopmental Capi tal Corp. announced it will begin rehabilitation work this month on 13 apart ment buildings totaling 70 units. To be built under provi sions of the HUD Section 236 program, the rehabili tation project will cost an estimated $1,081,000, ac cording to Jerome Rose nberg, RCC president. Contractor is Jonco Con struction Corp. and archi tect is Reinhard Lesser Associates. The apartments are lo cated in the south central area of the city of Los Angeles. When completed, the structures will contain 40 one-bedroom units, 10 two-bedroom units and 20 efficiency apartments. Redevelopment Capital Corp., a Los Angeles-based firm active in residential rehabilitation and new construction, has present ly under construction or in various stages of plan ning the rehabilitation of 150 apartment buildings containing more than 600 living units in Los Ange les.