Post-Earthquake Checks: What to Look at Before Reoccupying Your Building

After a significant earthquake, the instinct is to get straight back into your home or workplace. But a building can look fine from the outside and still have damage that affects its structural safety. Here's how the post-earthquake assessment process actually works in New Zealand, and what to check yourself in the meantime.

Right after the shaking stops

• Drop, Cover and Hold for aftershocks — they're common after a significant quake.
• Check yourself and others for injuries first.
• Staying inside is usually safer than rushing outside, unless the building is showing obvious signs of distress (new cracking, visible leaning, dropped ceilings) or you're in a tsunami evacuation zone.
• Keep phone lines free for emergency calls — use text or social media instead.

Who decides if a building is safe to use

After a significant event, territorial authorities can send out authorised Rapid Building Assessors (RBAs) to check buildings, under a methodology set by MBIE. They place one of three placards on the building:

• White — Can Be Used
• Yellow — Restricted Access
• Red — Unsafe, Do Not Enter

Only an authorised official can place, change or remove a placard — not the owner, and not a private engineer acting alone. If officials direct it during a state of emergency or a designated area, arranging a more detailed assessment becomes the owner's responsibility.

What a detailed assessment involves

Engineering New Zealand's guidance expects residential damage assessments to be carried out by a Chartered Professional Engineer, or by a supervised engineer with at least five years' relevant experience. The process typically includes:

• A non-intrusive survey first — level surveys, crack and verticality measurements, and photographs, compared against the building's likely condition before the event.
• An intrusive investigation (opening up linings, for example) if hidden or hard-to-see damage is suspected.
• Geotechnical input where ground movement or liquefaction may be involved.

Depending on the situation, engineers may carry out an Interim Use Evaluation for short-term occupancy decisions, or a more thorough Detailed or Targeted Damage Evaluation.

What to check yourself in the meantime

For a home that hasn't been placarded, a few practical checks can help you decide whether to call in a professional:

• Foundations: is the house still properly fixed down? If there's a subfloor, you may be able to check its condition and that fixings and bracing look intact — take care, or ask a licensed building practitioner to check if you're unsure.
• Chimneys: brick or unreinforced masonry chimneys are a known risk after shaking. Don't go near one that looks disturbed, and leave removal to a professional.
• New or growing cracks, doors and windows that won't close properly, or visible leaning: these point to possible structural movement, and are a reason to call a structural engineer rather than just a painter or plasterer.

Repairs and the Building Code

• Repairs generally only need to bring the damaged element back to the compliance level it had before the damage — there's no general obligation to upgrade the whole building.
• Reinstatement work can't leave the building, the site, or neighbouring property worse off for natural hazards.
• For most ordinary houses, the separate "earthquake-prone building" provisions don't apply — those generally only apply to buildings with two or more storeys and three or more household units. That doesn't mean a damaged house can be ignored; it still needs to be safe to use.

Insurance and next steps

• Don't do anything that risks your safety or could cause further damage while you wait for an assessment.
• Photograph all damage before any clean-up.
• Contact your insurer (and EQC/Toka Tū Ake for insured residential property) as soon as possible.

This article is general information for New Zealand conditions and isn't a substitute for a site-specific assessment. If your building has been through a significant earthquake and you're not sure whether it's safe to use, get in touch with Fil Engineers for an assessment.

Sources

• MBIE Building Performance — Rapid building assessment resources
• Engineering New Zealand — Guidance for Engineers on residential damage assessment and reinstatement
• National Emergency Management Agency — What to do after an earthquake
• Natural Hazards Commission Toka Tū Ake — Check your home is safe and secure