They only got as high as level one or two in the five-floor concrete structure: "It was not ideal... but from what we did see there was no obvious damage.''
But Canterbury Television staff were told later that day that the building had been inspected by a team of engineers and that they should feel safe going back there to work.
The green placard also meant the owner didn't have to commission a detailed engineer's assessment of the building.
The royal commission heard the contents of an email sent by Murray Wood, the 56-year-old manager of CTV who would later be one of 115 people killed when the CTV building collapsed.
Just hours after Mr Calvert, and his council colleagues Dave Flewellen and Russell Simson, found no concerns with it, Mr Wood relayed to his staff: "We've just had an internal inspection from three engineers and they found the building was in good condition and has been deemed habitable.''
Counsel assisting the commission, Mark Zarifeh asked Mr Calvert if that email summed up his own view of the inspection on September 7.
"No it doesn't because it wasn't assessed by three engineers'' he replied.
Mr Calvert was a council senior building support officer when the September 4 quake hit and he was seconded in to carry out rapid assessments of buildings, looking for damage.
He told the hearing today that he was "broadly aware'' of the process, having received a presentation on a Civil Defence course the year before.
However, he emphasised to the commission that he was not an engineer - and neither were either of his colleagues who were there on September 7.
They arrived at 11.45am and spent an hour inspecting the building, walking around the outside, and not seeing any major damage.
They spoke to the receptionist inside the building, and to someone he thought was the building manager, and claimed neither of them had any concerns over being inside the building..
"I have a very clear recollection of that,'' he said.
"There was no reason for any alarm with the CTV building.
"Nothing obvious required remedial action, otherwise I would've raised it with the building manager and receptionist.''
There was definitely no concern by either three of them, he said.
He did, however, accept after questioning from Mr Zarifeh that the inspection would have benefited from the expert knowledge of an engineer.
Zarifeh asked: "Would having an engineer in the group helped you appreciate the structural elements and what should've been inspected?''
"Yes, definitely,'' he said, adding that he did not think of it at the time as the team were "doing our job''.
He signed off the building as 'Green G2', which meant it was safe to be in but required repairs.
But on reflection , he wondered if he "meant that''.
"It perhaps highlights a degree of lack of understanding of Level 2 assessments.''
On the form, he wrote: "Looked at by 3 CCC (Christchurch City Council) senior officials - no issues sighted (sic) by users of building.''
He conducted more rapid assessments after February 22, but was accompanied by an engineer and a USAR member.
Earlier, Peter Van der Zee, a building consent officer, told how he was tasked with carrying out a Level 1 "visual'' inspection only of the building on September 5 despite not having any experience or training in post-earthquake assessments.
The hearing continues.
