Loudoun County school teachers won an 8.3 percent pay raise this week when the Board of Supervisors voted unanimously to adopt the school board budget without major changes.

The pay raise, effective in the next fiscal year, is more than double the raises proposed for teachers in Alexandria and Arlington, Prince William and Fairfax counties.

School Superintendent Robert Butt said he was pleased with the raises but told the supervisors the county should continue increasing salaries so that Loudoun can attract quality teachers.

The school board's $41.8 million budget was adopted with little fine tuning by the supervisors Monday, a change from last year, when the downturn in the economy forced the board to call for a $2 million cut in the school budget.

To avoid a similar problem this year, the supervisors directed the school board early in the budget process to limit spending increases to $1 million in local funds, and the board complied.

The school budget calls for an additional $1.1 million in local funds, most of which will go toward paying for the increase in teacher's salaries and a dental plan for school employes.

While the pay raise for Loudoun's 855 teachers appears large in comparison with the 3 percent offered in most other Northern Virginia jurisdictions, it actually is a move toward austerity in the Loudoun school budget.

In an effort to bring the county's teachers' salaries in line with the average salary in neighboring counties, Loudoun's school board began raising teachers' pay four years ago. Teachers got a 15.7 percent increase in 1981, 15.6 percent in 1982 and 10 percent in 1983. The increase of only 8.3 percent for 1984 has some teachers worried that the effort is over.

"If the school board decides not to finish the parity program it committed to three years ago, the recent raises will end up being only a Band-Aid," said Arjonah Bullock-Bulmer, president of the Loudoun Education Association. The LEA's 562 members requested a raise of 10 percent, which was also the figure recommended by the superintendent's committee on salaries and benefits.

Robert Jarvis, assistant Loudoun school superintendent, said the overall salary for a typical Loudoun teacher's 20-year career is 84.35 percent of what the average Northern Virginia teacher will earn. "But four years ago, before we started raising salaries," Jarvis said, "the Loudoun teacher earned only 78 percent of the average."

Jarvis also said the turnover rate among Loudoun teachers had dropped from 11.1 percent in 1980 to 4.3 percent this year, a success Bullock-Balmer attributed to the slowdown in the economy. But she said she fears the slowdown in turnover might reduce the pressure on the school administration to finish the parity program.

The board of supervisors deleted a $300,000 request from the school board to cleanup asbestos problems in five schools but voted to allow the school board to borrow the funds from the Virginia Public School Authority.

Asbestos was used in construction of Loudoun Valley and Broad Run high schools, Blue Ridge and Sterling middle schools and Douglas Community School 20 years ago, when many schools used the material because of its fire resistant qualities. Since then, however, asbestos has become suspect as a cancer-causing agent.