An expert witness at the Canterbury Earthquakes Royal Commission has faced fierce questioning over whether the Canterbury Television building met building codes when it was constructed in 1986.
Civil engineer John Mander was called by the building's designer, Alan Reay Consultants, to give evidence about the building's design and failure.
On Monday, he told the commission that the CTV building did meet design codes when it was built.
However on Tuesday, Professor Mander backtracked, saying that the assertion was based on other people's interpretations of the building code.
He said he did not have his own opinion.