After floods and slips comes the clean up – so where do you start?

After floods and slips comes the clean up – so where do you start?

The information in this story was first published after the Nelson and Marlborough floods in August.

Mud, silt and sewage have been left behind in homes in Auckland, Northland, Bay of Plenty and Waikato after torrential rain brought flooding and landslides to many parts of the North Island.

But, if you are allowed to return home, how do you clean it? Here’s what you need to know.

Before you start cleaning

While it’s tempting to get stuck, the first step is to stop, take pictures, and document the damage for insurance purposes.

* Roads linking Nelson and Blenheim remain closed as the full picture of damage unfolds
* In Photos: Four-day weather bomb that hit the top of the South Island
* Prime Minister Jacinda Ardern sees first-hand devastation in Nelson
* After the rain – what to do if your house has flooded

The Insurance Council of New Zealand Te Kāhui Inihua o Aotearoa and Toka Tū Āke EQC are encouraging people to contact their insurer before taking action.


Raewyn Flexman and family clean up Raewyn’s flooded home in the Waikato.

“They will let you know what to do next, how to claim and what damage may be covered by your insurance or EQCover,” says Tim Grafton, chief executive of ICNZ.

Karen Stevens, Ombudsman for Insurance and Financial Services, warns that repairs should only be done after speaking to your insurer.

And throughout the process make sure that everything is documented, she says.

“It is important to establish to your insurer what has been damaged and prove ownership. Your claim process will be easier with those documents to back up your claim.”

Get ready

Flood water is often contaminated with sewage and your home can be too, so you need to protect yourself.

“Flood water can make the air in your home unhealthy. When things get wet for more than two days, they usually become moldy. There can also be germs and bugs in your home after a flood,” advises the National Emergency Management Agency.

Andrew Freeman-Greene

Severe flood damage at a home in Auckland on Friday night.

“Mold can make some people with asthma, allergies or other breathing problems sick. “

Make sure you wear long sleeves and trousers – waterproof is even better – gloves, sturdy shoes and a mask or respirator.

Empty it

Once you’re admitted, make sure the power is off and then clear the house.

“Do not leave anything inside the home that can trap moisture and slow down the drying process,” advised a BRANZ guide, Restoring a Home After Flooding.

Anything that is wet should be dried out thoroughly – but if it has been contaminated or cannot dry properly, it may need to be thrown away.


Safunga and Seve Uatea are pictured outside their home in Clover Drive, Henderson, in the wake of intense flooding in Auckland

Residents are also advised to throw away any wooden spoons, plastic utensils and baby bottle spouts and dolls if they are covered by floodwaters. There is no way to clean them safely.

Any contaminated food – including vegetables in gardens outside – will have to be thrown away.

Any appliances affected by water will need to be checked before being plugged back in.

It is also recommended that you remove any valuables to protect against would-be thieves while you make the house habitable.

Along with cleaning up all the visible mud, BRANZ advises you to look for any trapped water and debris. This involves removing skirting boards, skirting boards and front panels to showers and baths, and cleaning any hidden mud and silt.

Andrew Freeman-Greene

Severe flood damage at a home in Auckland on Friday night.

“Remove wall linings sufficiently to allow cleaning of the wall cavity and removal of wet insulation material.”

If there is enough water available, and you are not still waiting for your supply to be reconnected, you can rinse walls and place them in hidden spaces to flush out dirt.

Come scrub

Once the debris is gone, it’s time to use the elbow grease – all surfaces should be cleaned with disinfectant to ward off flood-borne infections, the BRANZ report advises.

“Hard linings such as wood paneling or wallboard can be scrubbed with a stiff bristle brush, water and detergent to remove dirt from cracks, corners and crevices. The surfaces must be rinsed well with clean, cold water.”

If plasterboard is used for bracing, it will need to be completely replaced. In other places it must be cut off 300 mm above the flood line and only the affected part removed.


Floodwaters surrounded the Ormsby family’s home before they dramatically evacuated in a boat with their bedridden grandmother.

Other materials – such as those used for baseboards and architraves – may have swelled and will need to be replaced.

Getting out of shape

If mold has started to grow on liners, they will need to be discarded. Dr Mikael Boulic, senior lecturer, School of Built Environment, Massey University, says flooding provides perfect conditions for mold to grow.

“Mold is very difficult because you clean what you see, and you don’t clean what you don’t see. Mold grows according to temperature and relative humidity, and often it is invisible. Your most effective weapon against it is to dry out the house as soon as possible.

“If you have power (and it’s safe to use), turn on your air conditioner, a dehumidifier, and/or every fan you own. If you have a dehumidifier and an air conditioner, keep the windows closed to keep the air inside to help circulate and get rid of excess moisture. Keep your windows open if you only have fans, and if power and weather don’t permit, open all your windows and doors to create airflow.”

The Insurance Council says that when things are wet, they usually go moldy after two days. They also suggest opening cabinet doors and drawers to maximize air circulation.

BRANZ says any affected timber frame should be thoroughly washed, rinsed, treated and dried. If mold has been removed from the sides of a stud, it is likely to appear on the rear of the stud as well, and should be managed accordingly.

Floor coverings, such as vinyl and tile, should be lifted to speed the drying process.

Heaters and dehumidifiers can help speed up the process, but BRANZ advises against turning the heater up to high, as too much heat can warp and split wood. Try to keep the temperature at around 20C, and keep the windows open to allow moist air to escape.

Throw it out

Once you’ve worked out what can’t be salvaged – and sorted it properly with your insurance company – you’ll need to dispose of the rubbish.

Auckland Council says if you have insurance, contact your insurance company in the first instance to confirm the process for disposing of storm-related waste, including construction debris, soft furnishings and storm-damaged household items.

“A number of private waste companies can provide you with a container or flexi bag to collect your waste. A list of these companies can be found here [PDF].

You can also take your debris and damaged items to a waste transfer station in Auckland. A list of these can be found here.”

If you don’t have insurance, Auckland Council has arranged for waste to be taken free of charge at participating transfer stations in the Auckland region. If you want to take your waste to one of these stations, call Auckland Council on 0800 22 22 00 to confirm your visit.

A list of participating facilities can be viewed here.

If you do not have transport to go to a transfer station, mention this to the council on the same number above so they can determine the best option for collecting your waste.

For other towns, contact your local council for further information.

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