In an application to the commission probing last year's tragic roof collapse, James Keywan argues any such finding would be outside the inquiry's scope.
"The commissioner should now rule that he will not express any opinions, conclusions or observations that Keywan may have breached a duty of care," his application states.
"To do so would be tantamount to expressing an opinion that he breached the standard of care of professional negligence."
At the very least, Keywan's lawyer maintains, he should be able to introduce a report to counter expert evidence that "a duty of care in the design and construction of this roof was not exercised."
Keywan, now 87 and retired, designed the Algo Centre Mall in the late 1970s.
He has admitted he was "uncomfortable" with putting parking atop retail space, saying he had never done anything like that before, but it was what the owner wanted.
During his testimony in March, he also rejected any responsibility for the roof's substandard waterproofing, and said he didn't track the terrible leaking that beset the building from the start and ultimately led to its collapse.
"I didn't design any leaks," Keywan testified from Hamilton.
As it has done with the several other players, inquiry counsel has notified Keywan that Commissioner Paul Belanger might make a finding of misconduct against him in his final report due early next year.
A forensic report by NORR Ltd. for provincial police and entered as evidence at the inquiry concluded the design and construction of the mall was shoddy.
Keywan maintains police marching orders to NORR were to "take a view on liability and possible negligence," something outside of the commission's scope.
He has since had his own report prepared by architect Allan Larden and wants to introduce the document as evidence to rebut the NORR conclusions, or have him testify.
Initially, commission counsel agreed to admit Larden's report as evidence.
However, citizens' groups at the inquiry oppose the report's admission on the basis it has little new to offer, and that it speaks to potential civil liability, which is outside the mandate of the inquiry.
They also say lawyers involved with the inquiry have already had an opportunity to cross-examine the authors of the NORR report.
Belanger will now have to decide whether to hear from Larden.
The commission is also currently fighting with Bob Nazarian, the last owner of the mall, for access to several hundred documents over which he claims privilege.
Appeal Court Justice Stephen Goudge is expected to arbitrate that dispute by the end of the month.