The Great Christchurch Buildings Trust believes the Cathedral in the Square could be fully restored for around $67m, against Anglican estimates of between $104m and $221m.

However, the church’s spokesman, Rev Jayson Rhodes, says the Trust’s figures do not take into account inflation and escalation costs.

“It would be ill-advised to not include those figures for a project lasting a number of years,” Mr Rhodes said today. “No scheme is ready to start today.”

The church estimates that fundraising and preparation alone for full restoration could take up to 15 years.

In a press release yesterday, the Trust said it was confident of bridging the multi-million-dollar funding gap between the insurance payout and its $67m estimate for restoration.

It based the lower estimate on cuts in base isolation costs and fundraising fees, and said inflationary pressures could be avoided by fixed contracts and a shorter completion time of five to seven years.

Trust co-chairman Philip Burdon added that he would commit $1m of his own money towards the restoration.

However, Mr Rhodes said base isolation had to be included in any restoration estimate, along with increases in inflation and other costs. 

Base isolators are flexible bearings in the foundations to minimise damage in an earthquake 

“Our engineers have told us that, in their expert opinion, to take out base isolation would make the building questionable to further seismic activity,” Mr Rhodes said.

The church’s consultation on new designs for the Cathedral closes tomorrow.