REAL ESTATE

Apartment construction may have been up last year in Orange County, but construction of office buildings and factories was way down, according to the Construction Industry Research Board.

The board said permits issued by local governments for new single-family houses fell by 500 in 1987, from 9,812 in 1986 to 9,322. Apartments and condominiums, however, rose by nearly 300 units, from 15,101 to 15,372.

The value of building permits for offices, however, fell from $510 million in 1986 to $389 million last year. Factories and warehouses also dropped, from $197 million to $157 million, while permits for stores rose from $220 million to $256 million.

Despite the drop, the Orange County office market still is overbuilt. The increase in retail space may soon mean higher vacancies and lower rents in that market, too, experts say.