Engineered composite decking versus the tried and tested timber – which is better?

Composite and Timber Decking Materials

Whether you’re looking to repair an existing deck or start from scratch, consider the decking materials available in New Zealand and how they stack up against each other.

There are two main types of decking materials you’ll find in New Zealand:

Composite: ModWood, Futurewood, Ekologix, Timbertech, Permadeck to name a few
Timber: Hardwood (Kwila, Garapa, Vitex) or Softwood (New Zealand-grown Pine and Macrocarpa)

Wait a minute: what exactly is ‘composite’?
Composite decking, otherwise known as composite lumber or eco-decking, is a recycled plastic and wood fibre blend that has a timber-like finish.

And what’s the difference between hardwood and softwood?
The most common difference is the density. Hardwoods have a slower growth rate (than softwood), and are therefore usually more dense.


Comparison Guide

To choose a suitable material for your decking project, consider these five key aspects:

Budget – How much are you prepared to invest?
Aesthetics – What look would you like to achieve? Something sleek, or with character?
Environmental impact – Does your carbon footprint impact your buying decisions?
Maintenance – How much time are you willing to put into the care and upkeep?
Durability – Does the material suit your climate? And what lifespan are you expecting from your deck?

At a Glance

Ballpark Aesthetics Environmental Impact Maintenance Durability
Composite $100 to $200 p/m2 Synthetic Low – Medium Nil – Low 15 to 25 years
Timber $30 to $150 p/m2 Natural Medium – High Medium – High 10 to 20 years


The Pros and Cons

Pros Cons
  • Usually comes with a warranty
  • Has a higher resistance against scratches and termites
  • Doesn’t contribute to deforestation
  • Low maintenance (sweep and wash)
  • Suitable for most climates
  • Generally don’t warp or splinter
  • Plastic-look tends to appear as years go by
  • Temperature under foot on hot days
  • Amount of chemicals used in manufacturing process
  • Environmental concern of end of lifespan recycling
  • Prone to slipping with build up of grime
  • Generally more expensive than timber
  • Aesthetically pleasing with character and warmth
  • Large variety of grains, colours, textures and finishes
  • More affordable than composite
  • Some varieties offer options for untreated and eco-friendly timber
  • Flexible to rearrange into new layout
  • High maintenance if not left to silver off (clean, paint, oil or stain)
  • Contributes to deforestation
  • Restricted by timber type to suit climate
  • Prone to repairs due to fading, mould, termites and rot
  • Can warp and splinter over time


A Tradie’s Insight


Russell of Onsite Construction Ltd has built decks made out of composite, hardwood and softwood, and says each type serves a different market.

“The Ministry of Education chose composite for their decking project outside their classrooms, and there were a few layers to their choice,” Russell says.

He explains environmental considerations initially steered them towards composite, and child-friendly features such as no visible fixings or splintering played a large part in their decision making.

“Personally I think composite is a great product, but it’s better suited for commercial areas as it needs room for expansion and contraction which means larger gaps; and the average homeowner goes for a neater look to match their house.”



Russell had a homeowner last year who specified they would like Garapa timber, and fortunately the client had done their research as the timber requires a pre-seal on all four sides before assembling.

“The homeowners liked the colour of the timber, it was good to work with, had a really nice finish, and they were aware of the care needed to maintain their deck,” says Russell.

While there is demand for various timber imports, Kwila still remains a Kiwi favourite.

“Majority of people want their decks built with Kwila, but there are drawbacks; I’ve got a Kwila deck at home, and when the purple tannins leeched onto the concrete, the wife wasn’t happy,” laughs Russell.

He mentioned it had been under a year since he used a water-based sealer, and will most likely water blast it off to re-do it with an oil-based sealer for a better finish.

While Russell would choose hardwood for homeowners, he recommends premium grade Pine for rental properties.



Matthew Taylor of G&M Building Services says when it comes to Kwila or Pine, he would choose Pine all the way.

“Pine is cheaper than Kwila, and it’s easier to work with,” says Matthew.

He mentioned clients are opting for local Pine due to the lower cost of materials, and are willing to pay for repairs after the product starts to wane.

“Deck repairs are more common than new builds, and after a good water blast and a quality stain, it looks brand new.”


Keep in mind these three things:

Due diligence: The Forest Steward Council (FSC) provides independent certification of wood worldwide. They are a global, not-for-profit organisation dedicated to the promotion of responsible forest management. If minimising your carbon footprint is important to you, ensure to check this with any suppliers.

Treated Pine: New Zealand is yet to ban timber that is treated with chromated copper arsenate (CCA). The treatment prevents rot and decay caused by fungal attack, and resists insects such as borers and termites. There have been mixed reviews on the health concerns surrounding CCA, so it’s best to do your research before you decide on either material.

The other components: Be sure to account for the piles, joists, bearers, railings, and potentially stairs, in addition to the boards underfoot.


Want to find an experienced tradie who can help you with your decking project? Post your job today to make the most of your outdoor living area.