Renovations expert Jen Jones talks about eco-friendly design and sustainable materials for your next build or reno
In a perfect world, all homeowners undertaking a new-build or renovation would like the project to be as sustainable as possible. But for most of us, cost is a real factor. Will it be more expensive than a traditional build? The answer is… it depends. Investing in better quality materials from natural resources will likely be more expensive in upfront cost – but the key word here is “investing”.
Part 1 of our sustainable homes series:
How to create a sustainable home with small, incremental changes
If the quality of that product means it has a longer lifespan and doesn’t need to be replaced as frequently, is it really more expensive? Or in the context of infrastructure – investing in energy-efficient systems and solar energy now, means low or no power bills will eventually pay back, and your overheads will decrease.
It starts with design
If you can’t afford the very best or most sustainable option at every decision point, then start with a combination of the design and what is called basebuilding – meaning the core and shell. When it comes to new-builds the design of the home, from the orientation, footprint and specifications, has a big impact on how efficiently it will run, how expensive it will be to build and how much waste is generated in the process. The same goes for renovations, although on a smaller scale.
These are also the parts of the home harder to change later, which means it should be where you prioritise investment if you can’t have it all. Set the foundations for success, then improve the interior over time and as resources allow. Future-proofing your home for solar energy down the line is a good example of this.
Materials and infrastructure
When it comes to your basebuilding, the biggest decision you’ll need to make beyond footprint and layout is the materials you choose to use – particularly for exterior and interior cladding, roofing and framing. This is also the time to invest in infrastructure, even if it’s only to future-proof or add resilience.
Bricks
Arguably one of the most sustainable and versatile materials, bricks can be used indoors and out. Thanks to their density, bricks improve the energy efficiency of a home as they absorb and retain heat, helping to cool the home in summer and warm it in winter.
Bricks are made from clay and shale, and although this is a non-renewable resource, the positive attributes of brick and the ability to recycle them still makes them a top choice for building.
If you really want to level up your sustainability when using bricks, you can use slip bricks in construction. What this means is a slice of the brick is used rather than the whole brick, so you get a lot more mileage out of your order. On the outside, they look the same, but on the inside the reduced depth creates an opportunity to add extra insulation to your home without compromising on floor area. They’re also lighter, reduce the cost of installation yet still carry all the same benefits listed.
In the case of a renovation, if you don’t like the look of the existing bricks consider alternatives like a bagged or paint finish rather than replacing them. Remember to prime first to avoid efflorescence (crystalline deposits) as this can’t be easily undone.
Timber
There are a couple of considerations to keep in mind if specifying timber cladding for your home. One is the regular maintenance you have to be prepared to do to ensure longevity. The other is how the timber was harvested and processed.
Timber helps with heat regulation of the home. As a natural insulator, it resists the transfer of heat, meaning any heat loss through the cladding is minimised, which is great in winter. In summer it absorbs the sun’s heat and helps to stop your home from overheating.
Timber is a 100 per cent renewable resource that sucks up and stores carbon dioxide when grown; it’s already fighting the good fight before being used in construction, and as long as trees are replanted at the same rate they’re harvested, this will continue. The key to confirming this is to keep an eye on whether the suppliers offer Forest Stewardship Council (FSC)-certified timber.
Another consideration when reviewing suppliers is how they treat their timber. Chemical-heavy options are usually those available at the lower price end and will be marketed as being more durable, but the toxic chemicals used in the treatment are as bad for the environment as they are for you. Keep an eye out for thermally modified timber (TMT) options in New Zealand.
Rammed earth
If you’re not familiar, rammed earth walls are formed from soil that is only just damp enough to hold together, which is then tampered between shutters and rammers to compact it. The structure is similar to that of a concrete column (tied rebar) with timber or steel beams used to bridge openings. There are a few limitations to how it can be built, but the benefits far outweigh the inconveniences as it’s a natural product, low-maintenance, energy efficient, breathable, fire resistant, soundproof, durable and it even helps to control humidity.
However, it has a very distinct look about it and, although it can be painted, many choose to leave it exposed. Rammed earth homes are incredibly energy efficient to build and generate a very small amount of waste, giving it a strong case for being one of the most sustainable options for your home. You will need to make sure your architect is across how it translates to the new insulation requirements under the Building Code, particularly for the exterior walls.
Concrete
The most obvious use for concrete in the home is foundations, with the option to polish the interior surface in place of an overlay flooring. This would be an unnecessary additional cost in most cases. Concrete is highly durable, with a life expectancy of 100 years when maintained, which is double the alternatives (re-pile anyone?), as well as being both acoustically and thermally insulating.
As far as production goes, the energy requirements for manufacturing are less than the alternatives, which means its carbon footprint is lower. Add to that the fact it can be made with recycled materials and there isn’t much not to like about it. In some cases it can be used for wall construction as well, which is more commonly the case in larger scale multi-unit construction.
Roofing
Slate and clay tile roofs have for a long time been considered one of the most sustainable options due to their 50- to 75-year lifespan. They’re also one of the most commonly recycled roofing options available. The most sustainable roof is a well-maintained one, so completing an annual check of any wear and tear or compromised areas and repairing or patching them to extend the life of your roof is a sensible habit to get into.
Similarly, don’t assume that your metal roof needs replacing when it starts to look a bit aged. Sometimes extending its life is as simple as an acid wash and a repaint, which helps prevent it from ending up in landfill prematurely. It’s also a bit better in the pocket.
Roof materials to steer clear of? It’s a no from me on asphalt shingles and fibreglass due to their 20-year lifespan, which means you’ll find three times more asphalt and fibreglass going to landfill than terracotta and porcelain tiles.
Insulation
I feel strongly that if a hazmat suit, gloves and mask is the required PPE for your insulation installation it probably doesn’t belong in your house. In today’s market, we’re spoilt for choice. The most sustainable solution is a largely wool-based insulation (some poly is often needed for binding) because wool has incredible insulation qualities, as well as trapping air and moisture and even yucky chemicals.
There are also recycled polyester insulation options on the market, which is a nice narrative but can feel a little like greenwashing – diverting plastic bottles from landfill is great, but how about we address the actual problem and stop manufacturing plastic bottles? Plastic bottles also often contain BPA and/or BPS, which are endocrine-disrupting compounds, so I suggest reaching out to individual brands to ask if their insulation is free from both; and proceed with a wool option if you’re unsure.
Water
As far as water goes, the most powerful thing you can do is collect rainwater and use that for things like watering your garden, washing your car, or filling the kids’ paddling pool. By doing that, you’re not drawing down on the town’s supply which also means – if others follow suit – you’re less likely to end up in a water restriction period.
These days, most tapware already comes with inbuilt water restrictors anyway, so if your new shower head doesn’t feel quite as powerful as the last, that’s why.
Energy
There are a few ways to be more sustainable in the context of your energy consumption, and not everything needs to be considered during your build. You may have mixed feelings about an over-connected world, but there are a lot of benefits that come with smart technology in the context of energy consumption.
For a bit of background, New Zealand generates a lot of its power from renewable resources, and only really kicks into non-renewable generated power during peak times – think breakfast and dinner, Monday through Friday.
You may have noticed that some electricity companies offer different rates for your power usage at different times of the day or week. That’s likely due to a combination of renewable power not being as expensive (off-peak), and for some companies such as Electric Kiwi, it’s because they want to incentivise homeowners to “load-shift”. This is when you utilise power off-peak for things that quite frankly, can wait.
Delaying the start of your dishwasher, washing machine and dryer to late evening will cost you less, as well as being better for the environment. Most current-day models have the capability for you to schedule the start for later. Same goes for things such as charging your electric car at home, putting heated towel rails on timers, your hot water cylinder, air conditioner and considering things like a heat pump over column heaters, and a hot/cold boiling tap given the incredibly high draw of a kettle.
All these initiatives combined will help you to run a significantly more energy-efficient home, which all of a sudden, makes solar energy much more feasible as you’re not paying to install a system that can cope with your inefficient power consumption. Instead, you can downsize the system, add on a battery and almost entirely run your home on the sun’s rays, depending on the size and orientation of your home.
Doing our bit
Sometimes there’s no avoiding impact on the environment through the manufacture of products, so instead it’s worthwhile looking at the business and how they’re addressing that through other avenues. For example, are they net carbon neutral? Do they use recycled materials?
I think there’s also a common misconception that being sustainable means fringe-living or far more compromise than the reality. Really though, it’s about the ways we can be more considered during a renovation or new build. It’s not difficult to make small changes that suit our lifestyle and budget, while also lessening our burden on the environment.
If I could leave you with one thought to finish, it’s to never underestimate the cumulative impact of your actions on others. Like they always say, one plastic bag, straw or coffee cup won’t make a difference but if everyone says no to these things, it will. The same goes for construction.
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