Owners of pre-1976 buildings (except single dwelling residences) on which the city council has no building strength information have been sent a letter notifying them of the requirement to have the buildings assessed.
Council heritage policy planner Glen Hazelton said the letters followed a six-month desktop exercise by council staff to identify buildings on which the council needed information.
The assessments would be done at the owners' cost within the next two years and the information and the building's status entered into a register, added to land information memorandums (Lims) and council files and ultimately made public.
Under the council's policy on dangerous, insanitary and earthquake-prone buildings, if a building's strength was found to be less than 34% of the new building standard, owners would be given between 15 and 30 years - the less their strength, the shorter the timeframe - to upgrade to at least 34%.
That could change if the Building Act was amended following the Canterbury Earthquakes Royal Commission, Dr Hazelton said.
However, if owners wanted to change a building's use in the interim, they would be required to upgrade at the time of consent to 67% of the new building standard, as they had to comply "as near as reasonably practicable" with building code requirements.
Most of the letters had been sent, and the remainder would be posted within two weeks.
He declined to say how many letters had been sent, but it was "a significant number".
At this stage, building owners had to have an assessment done by a structural engineer, which he expected would cost between $500 and $1500.
Many buildings had already been assessed because tenants, insurers and lenders were increasingly asking for that information, he said.
Dunedin commercial property realtor Graham Stewart said earthquake strengthening had been "all the talk" among commercial property owners in Dunedin for some time.
The letters would come as no surprise to most, as the council had been foreshadowing this for years, he said.
He imagined most larger commercial property owners had already had their properties assessed, as tenants were refusing to take leases unless buildings were up to code and building owners, when advertising space for lease, were listing the level of compliance with the code.
The smaller buildings, such as those in George St, would be the most likely not to have had assessments done and probably the most likely to be under-strength, he said.
The market would probably drive how people responded to strengthening requirements and the outcome of assessments would be interesting.
The strength of buildings was already being used in advertising to attract tenants, he said.
Dr Hazelton said the assessment work would happen alongside a new targeted rates scheme which would make available financial assistance to up to 10 heritage building owners over the next year from the Dunedin City Council to allow strengthening work to proceed.
People would be able to apply to the council for up to $50,000 towards their strengthening projects. The money would be be paid back to the council through targeted rates, at 7% interest, over 10 years.
