Mr Ward is working at Totara Estate, removing Portland cement mortar from the historic stone buildings and replacing it with "proper" lime mortar - as it used to be.
He started about two months ago and is now just over halfway through work on the granary.
Portland cement was wrong for the buildings of that period, he said.
The procedure was relatively straightforward "as long as you know how to go about getting the proper recipe for the lime mix".
Totara Estate was the birthplace of New Zealand's frozen meat industry.
"What's contained here actually made New Zealand. This set up New Zealand as a country. This was the beginning [of the meat industry]," he said.
Mr Ward gained satisfaction from doing the work, which he hoped to finish by the end of July, and "achieving something".
"It's doing something that needed to be done and you're doing it right. It's something you look back on and think, `Yeah, I did that."
'Mr Ward was saddened to see the damage to heritage buildings in Christchurch after the earthquakes.
He worked on Christchurch Cathedral for just over a year three years ago and had worked on other heritage buildings, including the Provincial Chambers and the Rose Chapel.
Many he helped restore had either been severely damaged or were "completely gone".
"That's ... history gone down the gurgler," he said.
Mr Ward expected Christchurch Cathedral to be rebuilt, saying it was the focal point of the city, and he would be happy to help with restoration if asked.
He had a call after the first earthquake last September, asking if he was interested in helping with the rebuild.
It was "not everyday sort of stuff" that builders or blocklayers could do, and the work would involve plenty of carving.
"They are going to need people like me to do it. I wouldn't say no to going to give them a hand with it," he said.
