RICHMOND, NOV. 5 -- Workmen will begin a $628,000 postelection renovation Monday on the third floor of the Statehouse, starting with the suite of offices used by Gov. Gerald L. Baliles.

Financed by a little-noticed appropriation approved this year by the General Assembly, the project will be the first major renovation of the offices since 1904, according to Baliles' press secretary, Chris Bridge. Among other things, furnishings will be updated and new electrical and ventilation systems will be installed.

Asked whether the project was delayed until after Tuesday's election to keep Republicans from making it a campaign issue, Bridge said "those who are cynical" might choose to believe that, but "it was not practical to begin the work until after the election."

She said the governor was so busy campaigning for fellow Democrats the last two weeks that he didn't have time to prepare for a move. Similarly, Bridge said, there was no time in October to prepare for the renovation, even though the governor was out of the country more than half the month.

During construction, Baliles will work out of temporary facilities in the General Assembly Building, across Capital Square from the Statehouse.

Original plans called for the work to begin last month, during the governor's overseas trip, according to John Paul C. Hanbury, senior principal of the Norfolk architectural firm that won the contract.

"But at the request of the governor's staff, the start was delayed," Hanbury said.

GOP state party spokesman Steve Haner said, "As Gerald Baliles is so fond of saying, in politics, timing is everything." Haner said he hopes the work is completed by 1990, when a new governor takes office, "so some of my {Republican} friends can enjoy it."

Democrat Baliles and his staff will have plenty of time to enjoy the renovation. The 2,600 square feet of space used by the governor, his chief of staff and their secretaries, along with a ceremonial conference room and reception area, will be completed before the start of the General Assembly in mid-January, Hanbury said.

The remaining 5,000 square feet occupied by the governor's aides, including Bridge, will be fixed up after the legislature ends in mid-March.