Commission chair Chris Titus says suggestions that the coating would add 50 years to the life of the garage are only "theoretical." (CBC)

The chair of the Saint John parking commission says the new Peel Plaza Parking garage is being built to last 50 years and it doesn't make sense to spend money trying to make it last longer than that.

But a concrete expert says it is quite possible to build a garage that will last a century.

Earlier this week, city council was told the parking commission dropped plans to put an epoxy coating on the floors of the new garage, shaving $350,000 off the structure's $16.5-million price tag.

The commission made the decision based on the recommendation of the project's manager, Bill Edwards, who told city council the change of plans will reduce the anticipated life of the building from 100 years to 50.

"We didn't need to plan for 100 years, 50 years was sufficient," Edwards said, adding that it would have cost millions over the years to re-apply the topping every seven to 15 years.

"It will have no impact," he assured.

'That's not going to have any impact, as I understand it, on the life of the garage.'—Chris Titus, parking commission chairman

Parking commission chairman Chris Titus agrees. "That's not going to have any impact, as I understand it, on the life of the garage."

Titus denies his organization is trying to save money by not using the epoxy and contends suggestions that the coating would add 50 years to the life of the garage are only "theoretical.

"An economic decision that's based on sound reasoning as to why you would not spend that money to do something that would only speculatively increase the life of the parking garage beyond 50 years," he said.

But Doug Hooton, an expert in concrete durability and a professor of civil engineering at the University of Toronto, contends there have been many innovations to concrete construction in recent years that allow designers to predict life spans even beyond 100 years.

A well-built and well-maintained structure, such as a bridge, or parking garage can be made to last 100 years "if you know the type of concrete, and you know how far the steel is in from the surface, and you know what kind of surface coating you have and how long that will last," he said.

Hooton points to the Confederation Bridge to P.E.I., which was built to 100-year specifications.

"And on the roadway there they used a membrane on the road deck. And they also used what I call a very high-performance concrete that is very resistant to chloride ingress. And they put the reinforcing steel down really deep. The combination of those measures should allow it to last 100 years without corrosion," he said.