The head of the structural engineering firm that designed the Canterbury Television building says he accepts his firm is ultimately responsible for any deficiencies in its design.
The Canterbury Earthquakes Royal Commission is investigating why the building in central Christchurch failed in the 6.3-magnitude earthquake on 22 February 2011, killing 115 people.
The commission has been told there was lack of care was shown in the design of the office block and it was only one of the first of a new generation of multi-storey buildings in the 1980s in which precast concrete was used.
Alan Reay, of Alan Reay Consulting, was giving evidence at the inquiry on Thursday.
When asked if the building was well designed, he replied that he could not answer that question because he had not reviewed the plans and they had been overseen by one of his employees, structural engineer David Harding.
Mr Reay agreed that he was reserving his judgement on whether the building was well designed.
"You know, I look back and try and remember what the circumstances were at that time in my life when I was doing that, because I do accept that my firm is ultimately responsible."
Mr Reay extended his condolences to the families of the victims.
Evidence has already been heard that Mr Harding did not have experience in the design of multi-storey buildings.
Design showed 'lack of care'
One of the structural engineers who investigated the CTV building's collapse for the Department of Building and Housing was questioned by the lawyer for the building's designer.
Nigel Priestley was asked whether he agreed that the building could be classed as an innovative building when constructed in 1986.
Professor Priestley said he could not see any evidence of an innovative design process being used, and that a lack of care was shown in its design. He pointed to the designer's lack of experience in working on multi-storey buildings.
But the lawyer for Alan Reay Consulting attacked the department's investigation, which blames his client for the collapse.
Hugh Rennie said it is inappropriate for the department to come out with its findings before the Royal Commission has completed its work. He said his client's efforts to help it were rejected from the beginning.
"The first and continuing response of Dr Reay and ARCL has been to be investigate and so understand what happened. Their intention of doing this in cooperation with other investigators was rebuffed and, in particular, by the Department of Building and Housing.
"This rebuff is contrary to long-established professional principles and, rightly or wrongly, was seen as an implied accusation and with degrees of pre-judgement."