In its first step to reduce the city's costly surplus of old schools, the Washington school board has voted to close six red brick school buildings built before 1912.

Only one of the buildings, Blair Elementary, at 6th and I Streets NE, has any students in it. They are adults in basic education classes, which are being moved to a larger building nearby.

In the spring the board is expected to receive recommendations from Supt. Vincent Reed to close some schools that have regular classes - a move that will probably create much more controversy.

Besides Blair, the other buildings being closed now are Carberry, 5th and D Streets NE; Crummell, at Gallaudet and Kendall Streets NE; Dent, 2d Streed and South Carolina Avenue SE; Morse, 5th and R Streets NW; and Perry, First and M Streets NW. All were built as elementary schools from 90 to 65 years ago but have been used recently as either offices or warehouses.

Reed said that closing the buildings will save the school system about $250,000 a year in heating and maintenance costs. He said it also will allow 11 costodians to be reassigned to newer buildings, which don't have enough janitors to take care of them properly.

The surplus of schools was a major factor in the three-day "sick-out" in September by union custodians, who charged they had become overworked. Four large new school buildings opened last full but no extra custodians were added to take care of them because of a city employment freeze. Since October, Reed reported, 35 custodians have been hired.

The surplus of schools here is part of a nationwide phenomenon, caused by a drop in births and a decline in school enrollment. In addition, the District now is completing the largest school building program in its history even though the city already has a surplus of almost 9,000 elementary school seats.