The Loudoun County Board of Supervisors met last night to raise property tax rates by a nickel to $1.19 per $100 assessed value, becoming the first area jurisdiction to increase the rate in this year of the taxpayer revolt.

Even with the five-cent rise, Loudoun County retains by far the lowest property tax rate of any major area jurisdiction.

A $60,000 home in the county would be taxed $714 annually at the new rate. Actual tax bills will rise more than a nickel per $100 due to increased reassessments averaging 13 percent across the county.

The total Loudoun County budget for the year starting July 1 is $37.3 million with $26.6 million of that going to schools. The budget for the year now ending was $36.1 million with $24.5 million for schools.

County officials, describing the budget as a "hold the line" document said the tax increase was the result of an $890,000 appropriation for court-mandated renovation of the county's court facilities.

Board Chairman George Yeager said the court renovation costs accounted for seven cents of the rate. We've been very conservative. Without the court order, we would have been able to reduce the rate," he said.

Most of the rest of the increase in the budget was the result of cost-of-living and salary increases averaging about 7 percent for county employes and teachers.

The county has found itself in a squeeze on the courts, with bids on the construction work coming in more than $300,000 above estimates. The county board rejected the bids and Virginia Circuit Court Judge Ernest Ballou of Roanoke has given the county until Oct. 1 to decide how it will proceed.

The boards choices include deciding to spend the $2.7 million estimated cost of executing the existing plan or going back to the drawing board and developing more expensive, longer range plans.

Yeager, who has announced that he will resign to accept a promotion with Columbia Gas Co., in Charleston, W.Va., also said yesterday that he would not leave the board until July 11.

If the vacancy occurred before that date, a special election would have to be held in November to fill the seat. With Yeager's resignation coming on July 11, his Sterling District seat will be filled by appointment from the heavily Democratic board.

Republicans have called for Yeager to step down in time for an election, but Yeager has refused, saying that it would required a candidate to run in November, again in the spring primary and again in November 1979 in the general state election. "That just creates confusion," Yeager said.