Why old chimneys are a quake risk
The Natural Hazards Commission (NHC) says homes built before 1970 most likely have unreinforced brick or masonry chimneys. Heavy, tall and poorly tied in, they're the part of an older house most likely to come down when the ground shakes.
New Zealand has learned this the hard way. The one recorded death in Wellington in the 1855 Wairarapa earthquake came from a collapsing brick chimney. In the 2016 Kaikōura earthquake, NHC describes a Wellington family whose 1920s home's chimney collapsed metres from their baby's cot.
After the 2010 Darfield earthquake, BRANZ found the main effect on Christchurch houses was the loss of unreinforced masonry chimneys, and that damage to sheet roofing and metal tiles came mainly from chimneys falling onto them. The 2007 Gisborne earthquake led to 1,582 chimney claims, and the 1929 Murchison earthquake damaged chimneys in Nelson, Greymouth and Westport.
Signs yours deserves a closer look
- The house was built before 1970
- There's a brick or concrete stack sticking up above the roofline
- From the ground, you can see cracks, missing mortar or a lean
- Water stains on the ceiling or wall next to the chimney, which point to tired flashing
- Nobody has looked at it since the last decent shake in your area
- You no longer use the fireplace, so the chimney is all risk and no benefit
What are your options?
| Remove to floor level | Remove above the roof, fit a metal flue | Leave it as it is | |
|---|---|---|---|
| Suits | A fireplace you no longer use | A fireplace or burner you want to keep | Only a chimney you've had checked and are comfortable with |
| Quake risk | NHC's safest option: the whole stack is gone | Takes away the heavy brickwork above the roofline | Unchanged |
| Roof work | The hole is framed, roofed over and made weathertight | New flashing around the lighter flue | Keep the flashing maintained |
| Consent | May need one, depending on what the chimney holds up | Ask your council | None |
Does removing a chimney need a building consent?
NHC says removal may need a building consent. MBIE's Exemption 31 allows removing a building element, such as a chimney, from a building of not more than 3 storeys without consent, provided it doesn't affect the primary structure, any specified system or any fire separation.
That proviso is the whole question. Some chimneys are tied into the framing or carry load, and taking those out is a different job. Exempt work must still meet the Building Code and must not leave the house less compliant than before, so get the builder or roofer to tell you in writing why they think it's exempt, and ask the council if there's any doubt.
Character areas and heritage homes
Chimneys are often part of what makes an older street look the way it does. Dunedin's listed villas, for example, typically have brick chimneys with corbelled tops.
In Auckland's Special Character Areas Overlay (Residential), external alterations or additions need resource consent as a restricted discretionary activity, and taking a chimney off is an external change. For a house built before 1900, Heritage New Zealand says works that may modify or destroy a pre-1900 structure need an archaeological authority. Check your district plan before booking anyone.
After an earthquake
Keep everyone away from the chimney, the fireplace and the outside walls beneath it, and don't light a fire until it's been checked. Stay out of any room where bricks or debris have come through the ceiling. Don't go up to look: aftershocks can bring loose brickwork down without warning. Photograph what you can see from a safe distance on the ground, and if anyone is hurt or in danger, call emergency services first.
Claiming for earthquake damage
If your home insurance includes fire cover, which most policies do, you automatically have NHC cover for earthquake damage to your home. You claim through your insurer, which usually manages the NHC part on its behalf.
You have a maximum of two years to lodge a claim, but NHC encourages claiming within three months, because a longer delay can affect the assessment. NHC may also cover imminent damage, meaning damage that's more likely than not to happen in the 12 months after the event. Our guide to Natural Hazards Commission roof claims goes through the process.
If you find more damage after a claim is settled, NHC says to stop all work in that area and contact your claim manager straight away.
While you're thinking about the roof
Chimneys aren't the only heavy thing up there. NHC says a single roof tile can weigh up to 4.5 kg, and recommends replacing concrete or slate tiles with lighter options or making sure tiles are well secured to the framing.
BRANZ found many concrete and clay tile roofs in Christchurch's hill suburbs had tiles knocked off their battens because they weren't tied down or the ties had corroded. If you're removing a chimney on a tiled roof, it's a good moment to ask the roofer about the tile fixings too.
Planning a chimney removal
Decide about the fire
If you still want a fireplace or burner, plan for a metal flue above the roofline. If not, removal to floor level is the option NHC rates safest.
Check consent and character rules
Ask whether Exemption 31 applies, and whether your district plan controls changes to the outside of the house.
Get a quote that covers the whole job
It should say how far down the chimney comes, how the roof is made good, the flashing, scaffolding, removal of the bricks and rubble, and who repairs the ceiling or wall inside.
Expect scaffolding
WorkSafe's example control for roofing work on a house is scaffolding with full edge protection. Bricks being taken down also need a way to stop them falling on anyone, or an area people are kept out of.
Line it up with other roof work
If a re-roof or roof painting is coming anyway, doing the chimney first saves paying for access twice.
What you can do, and what needs a pro
You can
- Look at the chimney from the ground, with binoculars if you have them
- Stop using a fireplace whose chimney is cracked or leaning
- Keep children and pets away from it after any decent shake
- Check your district plan or ask the council about character rules
- Photograph it before and after work, for your records and insurer
Leave to a roofer
- Taking the chimney down, from scaffolding
- Framing and roofing over the gap, or flashing a new flue
- Checking whether the chimney carries any load
- Securing loose tiles or ridge while access is up
- Anything on the roof after an earthquake
What we'd do with an old brick chimney
If it's pre-1970 brick and the fireplace isn't used, we'd have it taken down to floor level and the roof made good, ideally before the next re-roof or repaint so the access does double duty. If we loved the fire, we'd keep the fireplace and swap the stack above the roof for a metal flue. Either way, we'd sort it before an earthquake makes the decision for us.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.