How to prevent a damp, cold and mouldy home

New Zealand's mild climate can trick us into thinking 'she'll be right' when it comes to the warmth of our homes. But according to the latest HRV State of Home Survey1, a third of Kiwis live in cold, damp, hard-to-heat homes, and that's bad news for our health, our homes and our wallets.

Happy and warm family in living room
ARTICLE Erin Reilly

Your family’s health

“New Zealand homes aren’t especially good at helping us to stay warm and dry…with one in five people moving out of a house because of factors such as dampness or mould,” says AUT Professor of Sociology Charles Crothers.
“The health implications of a cold damp and mouldy home are phenomenal,” agrees Auckland Refresh Renovations builder. “If you suffer from asthma, which many New Zealanders do, living in a cold, damp and mouldy home will exacerbate the problem.”
Lucky for us, there are confirmed changes to the Residential Tenancy Act which will make homes warmer, drier and safer for New Zealand.
These changes require rental properties to have any replacement or installation of insulation to meet the required standard, and all rental properties to install underfloor and ceiling insulation that meets the standard requirement, where accessible.

The structural integrity of your home

“If water gets into your walls, flooring and other building materials, your home is instantly weakened,” continues the Refresh Renovations builder. “I once visited a home that had mould all down the walls, water coming in through the roof, and wet beams and leaky water pipes under their house. It was an appalling living situation.
“You can do a lot to a house if it’s structurally sound, but in that situation, it was really beyond redemption.”

Don’t forget your wallet

Damp homes hit the wallet hard, says Manukau Refresh Renovation builder Corey Rambhai.
“Damp equals cold,” he says. “It takes much more to heat your house when it’s full of moisture. You can heat it as much as you like, but as soon as you turn the heating off it gets cold again very quickly. Not only is this inefficient, but it also drives up power bills.”
The HRV State of Home Survey backs this up, with some respondents claiming their monthly power bills can get as high as $1,000 because of moisture and poor – or no – insulation.
Insulation being added into roof cavity space


The first step to creating a warm, dry and mould-free home is installing insulation in your ceiling and walls, and under your floor. There are lots of insulation options out there, with the most common being glass wool and polyester-type products.
Insulation is required in the ceiling and underfloors if accessible. If you're renovating the walls of your home, then it is a requirement to install insulation into your walls.

What if you’ve got high ceilings with no cavity to fill with insulation?

“Install a false ceiling,” says the Refresh Renovations builder. “Cathedral ceilings give a great sense of space and light, but they can also be very cold. You only need 175ml or so to build a false ceiling and install insulation, so you can enjoy a warmer home without compromising on that space that many people love.


To have a warm home you need to have a balanced ventilation system. Think about where you dry your clothes - make sure that the moisture is being ventilated to the outside of your home, rather than into your ceiling cavity. Also, get your renovation builder to take a look under the house or under the ground to see what kind of moisture levels are there. If there is an issue, a moisture barrier can be installed to avoid moisture transferring into your home.
Think about your kitchen and bathroom extractor fans, too.
“Drawing steam out of your kitchen, especially rangehoods, or bathroom is great, but if moisture collects in the ceiling cavity you’ll encounter problems further down the track,” says the Refresh Renovations builder. “Always extract moisture from your kitchen and bathroom into the atmosphere, not into your ceilings.”
Top end rangehood


“Kiwis like to let lots of light into our homes, especially during summer, so we tend to have a lot of glazing around our properties,” says The Refresh Renovations builder. “Double-glazing lets a homeowner open their home up while keeping the warmth in.”
“Installing new double-glazing on an existing home can be expensive, though,” says John. “If you have existing wooden or aluminium windows, retro-glaze the windows instead of removing them and starting again from scratch – it’s much more economical.”


Fires, electric heaters and heat pumps are popular heating options, but keep a few things in mind.
“Panel heaters are great, but make sure you get one with a thermostat and timer,” says the Refresh Renovations builder.  “Schedule your heater to turn on and off throughout the day so your home maintains a steady degree of warmth. You don’t have to have it on full-boar; just keep the chill out of the air so when you get home from work your home is much easier to heat up.”
The Refresh Renovations builder warns homeowners against some styles of gas heaters, though.
“Avoid unflued gas heaters,” he says. “Gases generate H2O, so you could find if you use an unflued gas heater, you could also have a damp home.”
Double glazed windows help make your home warmer

Cheaper options

What if you don’t have much of a budget? Fortunately, there are plenty of cheaper – and simple – options to create a warm and dry home.
1. Lay thick building plastic over the ground under your house to prevent moisture build-up.
2. Repair any broken water pipes.
3. Invest in thick, lined full-length curtains.
4. If you’ve got high windows that curtains can’t reach, stick a plastic film over the inside of them to keep the heat in.
5. Use draught stoppers around your windows and doors, and fill in any holes or cracks that could let cold air in.
6. Don’t dry your clothes inside.
7. Put a lid on your shower cubicle to prevent steam from entering your bathroom.
8. Buy a dehumidifier.
9. Visit the Energywise website to see if you qualify for subsidised insulation.
1_The HRV State of Home Survey 2016 was conducted by Buzz Channel with participants sourced from buzzthepeople online research panel of more than 20,000 New Zealanders. We surveyed N=1450 respondents who were between the age of 18 and 74 years. The margin of error on this sample is +/- 3.6% at the 95% confidence level._

You might be interested in reading: Painting Q&A: preparation and removal.


Get in touch with Refresh to discuss your home renovation project

If you would like to discuss ideas and options for your home renovation project, please use the enquiry form on this page to provide us with your contact details. We will get in touch with you at a time that suits you to discuss your project. If you would like to provide us with more information about your project, we have a more comprehensive enquiry form on our "Get in touch" page too.
*All information is believed to be true at time of publishing and is subject to change.

Read Next

All Refresh Renovations franchises are independently owned and operated.

Get in Touch

Get in touch if you are interested in a quote or consultation

(Don’t worry - if you change your mind you can unsubscribe anytime)

Please Wait ...


Oops! Something went wrong while submitting the form.

Talk to a renovation consultant today

If you would like to find out how Refresh Renovations can support you with a high quality, efficient home renovation, get in touch today. Your local Refresh Renovations consultant will be happy to meet with you for a free, no obligations consultation.

Get in touch