Some federal government buildings in Ottawa's Tunney's Pasture area will be vacated in 2015, according to a representative from the Public Service Alliance of Canada (PSAC).

Nobody from Public Works and Government Services Canada responded to requests for information about the future of these buildings, but PSAC told the CBC's David Gerow some buildings would have new plans in four years.

Big Fix RELATED: 7 federal buildings in rough shape

Dominic Lavoie, who is in charge of health and safety for PSAC, said some workers could be moved to other buildings while other services might be privatized.

The large space of land at Tunney's Pasture, which includes 22 buildings and much of Statistics Canada, features four government buildings rated in "poor" condition, five in "fair" condition and five in "good" condition.

The four buildings rated in "poor" condition have caused some health issues, Lavoie said.

"There is a significant impact that we've noticed over time in people that are working in these older buildings," he said.

Long-term health problems among workers are hard to measure or link to old buildings, though, because the issues normally arise when employees no longer work in the building, he said.

Many workers have also said a lack of clean water is among the most common concerns of employees at Tunney's Pasture, according to PSAC.

Structural engineer predicts buildings will be demolished, not renovated

Many of the buildings were built in the 1950s and 1960s at a time when the emphasis was on quick construction and not on making things built to last, said Ottawa structural engineer Ted Sherwood.

Sherwood said many government buildings are deteriorating faster than they can be renovated and the problem is compounded at Tunney's Pasture.

"They weren't built in the expectation that they would last forever," said Sherwood, who teaches civil engineering at Carleton University.

He added many of the buildings are reaching the end of their "design life." The government has committed millions of dollars to fix the five buildings deemed to be in "good" condition, but the other nine continue to further deteriorate.

Sherwood said he has an explanation for that thinking.

"It's often cheaper just to demolish a building and rebuild it than to try to upgrade an existing poor building," he said.

Public Works, however, has not given any indication as to what its future plans for the buildings are.