Building Materials – Introduction

This section of the Building A Home In New Zealand series is an introduction into different building materials and why you may be interested in looking at both traditional and newer building materials.  There is a lot of content to discuss so the Building Materials has been broken into Windows, Thermal And Noise Wall Insulation, Attic Venting And Moisture Control, and Heating.  We recommend reading all of these before Choosing A Builder as some builders may not be comfortable with something that they don't have experience with.


Throughout time, building materials generally didn’t change that much over short periods of time.  The technology of earthen bricks stayed the same with an area over hundreds or thousands of years. All, until recently. Now, building practices are changing extremely rapidly because of significant and frequent advances in technology and studies in material science and engineering. Sometimes, improvements in technology are due to a better understanding of previously used inferior building practices. Examples of recent changes in building practices in NZ include increasing insulation, the prevalence of LED over incandescent lighting, and the resurgence and importance of vented attics.

However, this isn’t the limit of the technology that is out there.  Other countries apply more advanced building practices and newer technology in some aspects that NZ still hasn’t heard of and aren’t required by our building code. An international investigation of NZ building code showed NZ building code is so outdated compared to other countries that even the newest NZ houses don’t meet OECD countries’ building codes. An OECD report (2017) said the NZ Government "should consider modernising the Building Code – its standards are less stringent than those of many OECD countries". And the IEA report said the New Zealand Building Code is "below the standards required of most IEA countries with comparable climates".

We don’t believe that any one country has all the answers and by no means are all of the practices of one country better than all of the practices of another.  However, it would be naïve and foolish to ignore improvements that can have significant benefits for your home and directly improve your comfort or energy efficiency. It is possible today to build houses that are warm, dry, quiet, and secure without spending significantly more.  The initial cost will then be recouped in reduced energy, water, and maintenance costs.

We built our house in 2014.  We were familiar with US building practices and made efforts to understand NZ building practices. We noticed that the US does some things better like windows, ventilation, and insulation; while we preferred the NZ sewage return and roofing materials. We were able to combine the best of the international building practices with the best of NZ building practices and created a home that was better than either countries building practices alone.  This has resulted in a very warm and dry home that is comfortable all year around, especially in winter.

In the winter of 2015, our family was having dry sinuses at night because of the low humidity in our warm house. Our inside temperature would get down to 18°C at night (we don’t use our heat pumps or electric heating) and our hydrometer was stating the relative humidity would be 30-40%.  Having a warm home with lower humidity is normal in the US, so we went to Mitre 10 to get a humidifier to increase the relative humidity in our home, just as we would have gone to a similar hardware store in the US.  A summary of our conversation with the Mitre 10 employee is below:

Us: Good morning. Can you please show us to the humidifiers?

Employee: Sure. We have a wide selection of dehumidifiers right over here.

Us: I’m sorry, we are looking for a humidifier, not a dehumidifier.

Employee: No you aren’t, you need a dehumidifier.

Us: Our home has a low relative humidity and we need to add water to the air. Our current humidity is 30% and is drying out our noses. We need to add more humidity. Where are your humidifiers.

Employee: I’m sorry, we don’t carry those. There is no need for those in NZ. I still think that you mean you’re looking for a dehumidifier.

Note – I was eventually able to find a humidifier in a pharmacy in the baby section.

This is a great summary on the effects the different building practices in NZ. The US equivalent of Mitre 10, Home Depot, sells humidifiers for winter use and only small canister desiccants for closets, but not large electric dehumidifiers.  The US building practices are intended to keep excess moisture out of the home, so excess moisture isn’t a problem. Ironically, I passed a stand for a Karcher window squeegee / water vacuum designed to collect the condensation on windows in NZ as I exited the Miter 10 store.  We don’t have or need those with US windows either.

In this section, I will share some of the differences in the building code that may have the largest impacts on the comfort of homes in NZ. Some are very simple and can be very inexpensive to implement as well.  However, one option may not be the best solution for every build. We mention topics here to prime your thought processes so you can research them and discuss them with your builder. Though there may be some huge performance advantages, the below isn’t a direct endorsement for any specific technology.

One thing needs to be stated though concerning newer technologies.  Many builders may be hesitant to use something that they are unfamiliar with. We noticed that the bigger building corporations seemed to be more hesitant about new technology than the smaller ones. If you have something new that you would like to implement, bring it up with your builder when interviewing them. Some will be happy to learn from newer technologies; others won’t. Also remember that everything that goes into your home needs to prove that it meets NZ standards. Some NZ standards may be so outdated that newer materials don’t fit the mold of what has been previously accepted, and you will need to work with your builder and the supplier to provide what is needed for council approval.


Next Steps:

This brings to a close the introduction section of Building Materials.  The next step is to look at the first topic in new Building Materials - Windows.  This topic has had a revolution outside of New Zealand starting after WWII, but lack of education has prevented Kiwis from enjoying the benefits of more recent technology.