A planned $51 million renovation of the Poff Federal Building in downtown Roanoke is facing more opposition -- this time from the two U.S. senators who hailed the project a year ago.

In a statement Thursday, Democratic Sens. Mark Warner and Jim Webb said the three-year project could disrupt operations of the regional Veterans Affairs office, the building's largest tenant.

While that concern has also been raised by Rep. Bob Goodlatte, R-Roanoke County, the two senators stopped short of echoing Goodlatte's complaint that the project is a "waste of taxpayer dollars."

Staffers for Warner and Webb said they still support the original intent of U.S. stimulus funding for improvements to make the 14-story building more energy efficient.

But plans to relocate the Veterans Affairs office temporarily to four separate locations during the renovations could worsen delays and other shortcomings with the processing of veterans' claims, the senators said.

"We ask that you consider alternatives to the current reconstruction plan," Warner and Webb wrote in a letter to Eric Shinseki, secretary of the Department of Veterans Affairs, and Martha Johnson, administrator of the General Services Administration, which is overseeing the renovation project.

One such alternative would be to construct a new building to house the Veterans Affairs office at a cost less than the $51 million designated for the Poff Building renovation in the American Recovery and Reinvestment Act.

After the stimulus package was passed last year by Congress, Webb and Warner issued a statement that said the renovations would make the federal building more energy efficient and generate local jobs.

"I think what's new is a greater appreciation for how significant the backlog was at the VA regional office," Warner spokesman Kevin Hall said when asked about the change in course.

In January, a report by the VA's inspector general found widespread problems in the office, including improperly processed claims and a backlog that affects about one-third of the total caseload.

In recent months, Hall said, "there has been some pretty steady improvement, and this has been an effort to suggest that at least the current plan to scatter those operations ... would slow the effort to address the backlog."

Webb spokesman Will Jenkins said the letter was based on concerns that "the specific plan that has come out of the process is not the best option."

GSA officials, who last month awarded a $40 million contract to a Fairfax construction company for the bulk of the work, have previously defended the renovation as "a hallmark in taxpayer savings." Among other things, the project will replace the building's roof and glass walls, upgrade the heating and cooling system, and renovate the restrooms.

While no new location has been suggested, the possibility of moving the VA office away from the downtown area has city officials concerned about the loss of business from the agency's 400-plus employees and the veterans they serve.

When the topic came up at recent meeting of the Roanoke City Council, City Manager Chris Morrill said a presidential executive order encourages federal agencies to remain in downtown areas.

According to the GSA, work on the building is not slated to begin until spring.

Staff writer Michael Sluss contributed to this report.