Timber vs. composite decking: A comprehensive guide for New Zealand homes

When it comes to a comparison of timber vs composite decking, it's important to first state that it's not a matter of concluding that one is "better" than the other. If this were the case, the choice would be straightforward, which it is not as both are popular choices in New Zealand. Instead, the process is about understanding the specific traits and qualities of both, side by side, and deciding what is best for you. In doing so, you'll pick the option that better suits your needs now and for years to come.

The very first thing to do before diving into the details of this subject is to clearly define the two decking options. While this may seem obvious on the face of it, there may be some distinctions and nuances that surprise you which could be one of the things that sway your decision one way or the other.

What is timber decking?

Timber decking simply refers to outdoor decks constructed from natural wood materials. These include softwood and hardwood options, some of which are locally sourced with others imported. Treated radiata pine is the most popular locally sourced softwood option while Kwila is typically the most popular imported hardwood decking choice.

Given our unique and diverse environmental conditions up and down the country, it's important to pick the right species for your home and location (more on this to come).

Related article: Different timber decking options — what is best for your home?

What is composite decking?

Composite decking is a modern decking material manufactured from a blend of wood fibres, plastics, and other recycled materials. This composition is designed to mimic the look of natural wood while offering resistance to some things that can affect timber decking.

There are many different types of composite decking products, all with a variety of colours, textures and traits some of which can be quite subtle from one to the next.

One of the most important factors when it comes to any deck material is its performance, i.e. how robust and hardy it will be and how long it will last. Having a good idea of this in advance will allow you to better understand the return on investment over its entire lifespan.

Performance of timber decking

The performance of timber decking in New Zealand conditions depends on several factors, including the type of wood used, the quality of construction, and the diligence of ongoing maintenance. Assuming the last two things will be done well, focusing on the former is the best way to differentiate one option from the next.

The main choices you'll probably be considering for wood decking in New Zealand are softwoods like treated radiata pine and hardwoods like Kwila and Vitex.

Treated radiata pine is widely used for timber decking in New Zealand as it is readily available and cost-effective. When properly treated and maintained, you can expect it to last 15-25 years.

Kwila and Vitex are popular choices for hardwood decking that are naturally resistant to decay and insects with a lifespan of 25-50 years when properly maintained. They do, however, tend to come at a higher cost compared to treated radiata pine.

Performance of composite decking

One of the main appeals of composite decking is the longevity it boasts to homeowners. Many manufacturers offer warranties on their products of 15-25 years while some offer as much as 50 years.

Its composition of wood fibres and plastics is what gives it its resistance to rotting and decay. It is also resistant to moisture penetration (highly relevant in New Zealand's wet climate) and insects. On top of this, the inclusion of UV stabilisers helps reduce fading and degradation from the high levels of ultraviolet light we get in New Zealand.

Related article: The best decking materials in New Zealand

When thinking about a composite deck or a timber deck, the appearance and design are crucial factors. As such a visible feature of your home, you want it to look the part as well as play the part and it's an area that is unique and personal to everyone in different ways.

Appearance of timber decking

Timber decking has many admirers thanks to the natural warmth it brings to the eye and the unique qualities in the colouration, grain and texture that you can find. As discussed, there are many native and imported timber species to choose from which can have quite different looks from one to the next.

Radiata pine, for example, has a light tan colour with distinctive growth rings. Vitex, on the other hand, has a creamy-grey colour that will also darken if left to weather, bringing another trait into the equation. On the topic of changing colours, wood decking can also be painted and stained, giving you the flexibility to quite drastically change the appearance of your deck in time.

In terms of design, wood is incredibly adaptable, not just in look where it suits both traditional and contemporary architectural styles, but in form and layout. Timber decks can be laid in various patterns, such as horizontal, vertical, diagonal, herringbone, parquet etc to create visual interest and define different areas of an outdoor space. This flexibility allows for personalised designs that reflect both a homeowner's individual style and day-to-day needs.

Appearance of composite decking

There are many composite decking brands in New Zealand offering a wide range of colours, from natural wood tones to greys and even more vibrant colours for those after a bold and striking look. This also gives homeowners the freedom to match the existing colours of their home or garden.

Composite decking also allows you to create a uniform look for your deck, with composite decking boards typically the same size from one to the next. This consistent, cohesive appearance often aligns with modern and contemporary homes where minimalist aesthetics are favoured.

When it comes to design, composite decking can be cut with a circular saw and installed much like timber, allowing for a variety of design configurations, from simple linear patterns to intricate inlays and border designs. Many composite decking systems also come with integrated accessories like railing systems and hidden fasteners which again enhance the seamless look and finish that it's known for.

Related article: Deck ideas that make a difference — From stylish homes across the country

The environmental impact and sustainability of both timber and composite decking are where most people think the greatest point of difference will be, with the more natural timber options being perceived as better. However, while there is some truth that feeds into this perception, the reality is a little more complex.

Environmental impact of timber decking

The argument for the positive sustainability and environmental impact of timber decking is largely grounded in the use of timber as a renewable resource from sustainably managed forests. This commitment is supported by certifications from organisations like the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC), ensuring that timber is harvested in an environmentally responsible manner.

The use of locally sourced timber, such as radiata pine from managed plantations, not only reduces the environmental footprint by minimising transportation emissions but also contributes to carbon sequestration, as the timber acts as a form of stored carbon. Moreover, natural timber's biodegradability means it can decompose at the end of its life — a sustainable alternative to non-biodegradable decking materials.

However, environmental concerns arise with the use of chemically treated timbers for enhanced durability, which can have harmful effects if not properly managed, and the carbon footprint associated with transporting imported hardwoods like Kwila. In New Zealand there are regulations on the use and disposal of treated timber and an increasing number of people, when looking at imported options, look for those with sustainability and environmental certifications.

Environmental impact of composite decking

Composite decking, especially modern options, is a step towards more sustainable decking materials, especially when considering the entire life cycle of the product.

The production of composite materials utilises recycled materials, such as reclaimed wood and recycled plastic, which helps reduce waste and lessen the demand for virgin resources. This recycling process not only diverts waste from landfills but also minimises the environmental footprint associated with the production of new plastic and wood products. Additionally, the durability of composite decking and the long warranties that come with it, reduce the need for frequent replacements placing less pressure on our resources as a whole.

However, the sustainability of composite decking also depends on the energy-intensive manufacturing process and the eventual end-of-life disposal. While it is durable and resistant to decay, it is not as easily recyclable at the end of its lifespan compared to natural wood, which can biodegrade or be repurposed. However, this is mitigated by its long lifespan, low maintenance requirements (eliminating the need for chemical treatments and stains), and the use of recycled materials in its production.

Pricing is a huge factor when it comes to purchasing any product and decking materials are no exception. Also like most products, the price points can vary widely, even within each type, but you can still make valid comparisons above and beyond the initial purchase price.

Cost of timber decking

The cost of timber decking is influenced by several factors, including the type of timber selected, installation complexities, and also regional factors like the cost of transportation.

Treated radiata pine can cost between $3 - $10+ per linear metre making it a fairly cost-effective option in the market which softwoods tend to be.

Imported hardwoods like Kwila and Vitex tend to be more expensive and can range anywhere from $8 - $12+ per linear metre for Kwila and a bit more for Vitex which can be over $20 per linear metre.

Maintenance and longevity are also crucial cost considerations. Regular maintenance, including cleaning, staining, and/or oiling, is necessary to preserve the deck's appearance and extend its life, contributing to the long-term costs. While softwoods may be less expensive initially, their potentially shorter lifespan and higher maintenance needs could lead to greater expenses over time compared to more durable hardwoods.

Cost of composite decking

Composite decking can present a higher initial investment compared to traditional timber options, with material costs generally ranging between $100 - $200 per square metre but it depends significantly on the quality and features of the composite product. This price does not include the additional installation components like clips and screws, which adds to the initial cost. The variety of composite decking solutions available does allow homeowners to choose from basic to premium options, with the latter offering enhanced aesthetics and durability.

Installation costs are influenced by the design complexity and local labour rates, but composite decking often requires less labour than timber as it is lighter, has uniform sizing and is designed with easy installation features. The long-term value of composite decking is also influenced by its low maintenance requirements and durability, offering substantial savings over the deck's lifespan without the need for ongoing treatments.

Last but not least, the ongoing maintenance and care requirements of both options are another key factor. Given the busy lives that most homeowners lead, this can again be something that strongly sways a decision, one way or the other.

Maintenance requirements of timber decking

Timber decking does require regular maintenance to preserve its appearance and durability given the diverse weather conditions experienced in most parts of the country. These actions may be more important in some regions compared to others given the extremities of the weather that may be experienced.

This can include an annual deep clean with a cleaning solution to remove grime and mildew. It can also include staining or oiling every few years to shield the wood from moisture and UV damage. You may also want to conduct routine inspections for wear, damage, or structural issues are necessary, with prompt repairs needed to address any identified problems, such as loose boards or rotting timber. Ensuring good water drainage and protecting the deck from excessive sun exposure with UV-inhibiting finishes can also help mitigate decay and fading.

Maintenance requirements of composite decking

Homeowners are often most drawn to composite decking solutions for their low maintenance attributes and minimal upkeep. However, there are still some things that should be done to maintain it. Routine cleaning tasks should involve regular sweeping to clear debris and periodic washing with soapy water or specialised deck cleaners to tackle dirt and grime. Immediate action is recommended for spills to prevent staining, with specific cleaners advised by manufacturers for more stubborn stains.

Despite its robustness, composite decking can be susceptible to scratches and damage from heavy outdoor furniture or sharp objects, meaning cautious handling and the use of protective pads under furniture legs is recommended. In environments with high moisture or in shaded areas, vigilance is needed to prevent mould and mildew, with regular cleaning and proper ventilation being key preventive measures.

As you can see, there are compelling reasons to consider building a composite or a wood deck in New Zealand. However, now that you have a comprehensive understanding about the qualities and characteristics of both, you'll hopefully be in a position to make an informed decision for your decking project resulting in a deck that will meet all your needs.