John Kadlec, a structural engineer on the Algo Centre Mall project, testified the shoddy workmanship he saw three decades ago was unprecedented in his experience.
"I'd never seen that many deficiencies in my life before," Kadlec said.
"I sent letters warning (the owner) about sloppy workmanship."
The discovery of off-kilter columns prompted an unusual fix in which the construction company, York Steel, anchored the building to an adjacent rock face, the probe heard.
Despite the problems, Kadlec ultimately signed off on the construction of the mall, which collapsed last summer killing two women.
Based on reports from an inspection company, he said he was satisfied the deficiencies had "apparently" all been rectified.
Lawyer Joe Bisceglia, who speaks for another engineer who later inspected the mall, was incredulous at Kadlec's seemingly nonchalant approach.
"It's not every day that a building you design is out of plumb and is in such a condition that it has to be anchored to the side, in essence to a rock cut," Bisceglia said.
"They put in anchors without consulting you and without making you inspect it and approve it?"
The engineer defended his actions, saying he was part of a team and decisions were made elsewhere. He said he only visited the building site three or four times and relied on inspection reports which outlined the deficiencies.
At times, it was difficult to tell whether Kadlec — who emigrated from Czechoslovakia in 1970 — was having language difficulties.
"Are you happy with this?" he asked Bisceglia at one point after a tortuous attempt at questions and answers.
At other times, he simply said he could not remember events or was unable to answer the questions.
Kadlec, who worked for Toronto-based Beta Engineering, also testified he was puzzled by the "unique" decision to put the parking garage above the mall when usual practice was to put it underground.
He said he discussed his reservations with the original mall owners — Algocen Realty Holdings — to no effect.
"I didn't like it, especially in this area," Kadlec said.
"We talked about it. I was a small man, but the decision was made somewhere else."
The roof began leaking immediately. Asked if he ever warned the owner about the corrosive effects of water and salt penetrating the roof-top garage, Kadlec said he didn't realize the problem was so serious.
Investigators believe water and road salt combined to destroy the weld of two steel structures, leading to a catastrophic collapse of the pre-cast roof deck that rained rubble down on shoppers and mall staff.
Kadlec said he couldn't remember if he had designed the structure to avoid a "progressive" collapse.
He also said he had no idea the system used to waterproof the roof had never been used before in North America, the inquiry heard.
"I know nothing about waterproofing, even to today," Kadlec said. "It's a different profession."
Kadlec testified he can now only practise engineering by working with or for another professional engineer. The limitation is the result of another ill-fated project in which he was involved: the roof of a mall in Sault Ste, Marie, Ont., collapsed in 2009.
Also Wednesday, senior commission counsel Peter Doody confirmed a Canadian Press report that the inquiry was set to take the unusual step of taking the mall's last owner to court.
Doody said the commission had instructed lawyers to seek a contempt citation against Bob Nazarian in Divisional Court for his failure to produce thousands of emails.
"It is a serious step but we are determined to obtain all the evidence that's relevant to our mandate," Doody said in an interview.
The court is expected to hear the case — which also involves Nazarian's son Levon and wife Irene — in two weeks.
Doody said he could only recall one previous case in which a commission sought a contempt citation. That occurred during the inquiry into allegations of a pedophile ring in Cornwall, Ont., when a key witness refused to testify.
The inquiry continues Thursday, with two witnesses involved in the construction of the roof at the Algo Centre expected to testify.