POULSBO — When the state Legislature changed from the Uniform Building Code to the International Building Code as the state’s standard in 2004, not many people noticed.

Now, with winds of controversy swirling around the city’s municipal campus project, supporters of both the 10th Avenue site and Creekside Center have presented their own interpretations of what the code means. City officials have said bringing an existing building up to the new code requirements would cost millions of dollars, while others have strongly disagreed.

In an effort to bring some outside clarity to the matter, the Herald asked the National Council of Structural Engineers Association to weigh in with its thoughts.

The response came from the Structural Engineers Association of Washington’s earthquake engineering committee.

“The Uniform Building Code (UBC) and the International Building Code (IBC) have structural requirements that differ, sometimes considerably, but both codes are most readily applied to new construction,” the statement read. “Their treatment of existing building seismic performance is similar.”

Structural engineers often perform seismic evaluation and rehabilitation of existing buildings using national standards developed by the American Society of Civil Engineers (ASCE), it read.

“However, where additions, alterations, or repairs are made or where the use or the use of a building is changed, the local jurisdiction may require all or part of the building to comply with either the current building code or equivalent provisions for existing buildings,” it continued.

The requirements related to fire and life safety, energy efficiency and seismic performance can have a significant impact on the costs of renovating an existing building, it read.

“Determining that cost and deciding whether to replace or renovate often involves studies by architects and engineers, development of cost estimates based on those studies, and consideration by other stakeholders,” the response stated.

However, certain classes of buildings designed and constructed under previous building codes are sometimes found to be in compliance with current seismic standards without further evaluation or retrofit, it said.

Ronald O. Hamburger, a structural engineer with Magnusson Klemencic Associates in Seattle, provided more insight into the seismic requirements.

“The UBC provided design criteria to resist earthquakes that might occur one time every 500 years,” Hamburger wrote. “The IBC, which was specifically formulated to apply nationally, as opposed to only in the Western U.S. bases design on an earthquake that might occur one time every 2,500 years.”

That criteria makes the IBC more restrictive in Washington than other states, he wrote, noting that there are also many changes to fire life safety and other requirements in the IBC.

“It is unlikely a building design (done to the standards of) the 1994 UBC would be found to be hazardous,” Hamburger wrote. “Although the city may believe it is obligated to upgrade the building, this is likely not the case.”