Other risks include the complexity and costs of appropriate redevelopment and demolition being allowed to happen too easily.
Such challenges are confronted in a draft heritage action plan to be discussed by the Dunedin City Council tomorrow.
It is supported by 35 proposed actions that could occur over three years, although resourcing would need to be approved for some.
Among proposed actions is investigating changing the fee structure for heritage resource consents that affect heritage buildings, including seismic strengthening.
Others are to review Dunedin Heritage Fund eligibility and priorities to increase support for seismic strengthening projects, and consider a "heritage navigator" process that would be similar to laying out the "red carpet" specifically to support heritage buildings.
The problem of "demolition by neglect", where building owners allow heritage assets to deteriorate to a poor state, could be reduced through a series of ways, the report suggests.
This might include identifying the top 25 at-risk neglected buildings to focus resources on engaging with owners of such places.
Various other potential actions to protect and celebrate built heritage could include asking the community for nominations about places that should be assessed, investigating incentives to encourage occupation of vacant buildings, developing a video showcase of recently completed adaptive re-use projects, and working with mana whenua to identify significant Māori-built heritage.
"Our heritage buildings are both the stars and the supporting cast of the city — the University of Otago’s heritage buildings have seen it ranked among the most beautiful campuses in the world," the report said.
"The recently completed conservation of the exterior of the Dunedin Railway Station is an outstanding example of maintaining and repairing historic building materials."
Dunedin has 784 scheduled heritage buildings, 10 commercial heritage precincts, and nine residential heritage precincts that together contain more than 925 character-contributing buildings, 50 heritage structures and 41 scheduled archaeological sites.
Heritage buildings are described as an irreplaceable finite resource.
Recent changes to national seismic regulations — requiring certain buildings to be assessed for performance and, if necessary, strengthened — present "a substantial and disproportionate risk of losing historic buildings".
"The risk of demolition is likely to increase as the deadline for compliance with seismic requirements approaches."
For almost all of the city council’s territory, site owners would have 35 years to either strengthen or demolish an earthquake-prone building.
The council has assessed 1643 buildings as of November 1 this year.
Of those, 159 are considered earthquake-prone.
A minimum of 4400 buildings are still to be assessed by 2032.
1. More heritage places are adapted for re-use, conserved and upgraded to comply with code requirements.
2. Earthquake-prone historic buildings are strengthened, rather than demolished.
3. Demolition by neglect is reduced.
4. More places with significant heritage values are identified and protected by the district plan.
5. Heritage places are understood, valued and promoted.
6. Vacant sites in heritage precincts are developed with sympathetic and high-quality new buildings.
7. The Dunedin City Council shows leadership in looking after its own heritage places.
8. Dunedin builds a workforce trained and experienced in trades and professional services for heritage buildings.
Source: Ōtepoti Dunedin draft heritage action plan