ARTICLE Joanna Mathers
Decks are especially effective when it comes to opening up our indoor spaces. They provide the perfect place for outdoor entertaining, add extra square metres to a home’s floor space, and offer sun worshippers a spot to soak up the sun year round.
Installing a deck requires a bit of planning and forethought. There are council rules and regulations to be followed, and decisions to be made about the materials, cost, and colour of your deck. If you are considering installing a deck in your home, here are some tips on materials and costs for different options.
Wood is the material that springs to mind when we think of decks, and continues to be the most popular decking material. It’s aesthetically pleasing, fits seamlessly into the natural environment, and with regular maintenance can remain attractive for years.
Wooden decks fall into two categories – hardwood and softwood. Each option has its pros and cons, and your choice of wood will be dependent on budget, aesthetics and environmental considerations.
Hardwoods are long lasting and attractive; they are also significantly more expensive than softwood. They are prized for their attractive grains and rich colour, but can split and discolour if not maintained. The use of some hardwood in decking has attracted controversy. Illegal logging in rain forests has seen many areas of pristine jungle decimated – so it’s important you investigate any hardwood’s provenance before you make a purchase.
Kwila is one of the most popular hardwoods for decking use, but its popularity has led to the decimation of many ancient rainforests in Indonesia. While some kwila is certified as sustainable, there is still a lot of debate around the ethics of using this wood. It is also known for its tendency to bleed – it has water soluble tannins which can stain surrounding tiles or concrete.
Vitex is another popular hardwood. This creamy-grey timber bleeds less than kwila, and weathers to an attractive silver-grey colour tone. Mike Gibbs from JSC Timber says that vitex is a “middle of the road timber” in price and quality, and is very popular with customers.
JSC Timber sources their timber from the Solomon Islands. “About 90 per cent of the vitex we source comes from community sawmills there,” says Mike. “So the money goes back into the community.”
Other popular hardwoods include Pacific jarrah and garapa. Both of these beautiful South American woods are ideal for decking. It’s important to choose Pacific jarrah and garapa that is certified sustainable – FSC certification is a good example.
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.
Their independent certification lets customers know where timber comes from, and helps them make an informed decision. Softwoods are cheaper than hardwood, but require more maintenance and aren’t as long lasting. Radiata pine is the most popular and readily available softwood for decks in New Zealand. It’s lighter in colour than the hardwoods and needs regular painting or staining. Macrocarpa is another popular softwood; it looks similar to kauri, and has a fine grain and speckled appearance.
Eco decking is made from recycled materials, usually wood and plastic combined into a comparatively eco-friendly composite material. The wood provides a natural look and feel to the product, while the plastic component protects the wood from moisture and means the finished product is virtually maintenance free.
Composite decking has been used in the United States for around 30 years, but our high UV levels made the plastic components of earlier composite decking warp. Advances in technology have enabled new composites to be developed, which hold up in New Zealand’s harsh UV rays.
As well as being a more eco-friendly option, eco decking has other benefits.
Craig Fountain of Outdure explains: “Unlike wooden decking, our eco decking keeps its colour. A person could spend a million dollars on a house with a wooden deck, but within the year the deck will look old. This doesn’t happen with eco decking. “It’s is also easy care, non-slip and splinter-free, which is great for children and pets.”
Installation of composite decking is “not difficult, but different” says Virginia Gibson of Hybrideck. She recommends that builders spend time researching installation techniques before building a composite deck, as it has very different qualities to wood. Both Outdure and Hybrideck have instructional materials to help with the installation of their products.
Bamboo is a relatively new product in the decking market. It is the world’s most renewable plant source, growing to maturity in five to seven years, and the wood is harvested over and over from the same plant. After cutting the bamboo strips are bleached, carbonised and dried, then glued together under pressure, and molded into a solid piece suitable for decking.
Although bamboo is claimed to be environmentally friendly it is important to check the chemicals used during manufacture, as some are nasty and can produce fumes. Be sure to go to a reputable supplier so you can check out the provenance of the product you choose.
Evoca is a bamboo decking brand based in Christchurch. Sales manager Kent Ramsay says that bamboo has an edge over other wooden products when it comes to the environment. “Basically, it’s great to know that the product you’re using isn’t decimating rainforests,” he explains. “Additionally, bamboo has excellent density and strength.”
When looking for bamboo decking, it’s a good idea to check that it has been certified by an independent authority such as FSC to ensure it’s not being grown unsustainably.
Wooden decks need proper maintenance. If left uncared for they can become discoloured, slippery and unsafe. A tired deck can be brought back to life pretty easily, however, given a bit of preparation and some elbow grease.
Weathered bare timber can be spruced up by scrubbing with products such as Cabot’s Deck Clean. This is diluted with water and scrubbed into the surface with a stiff bristled brush.
The solution is left for 20 minutes, before being washed off with a hose on high pressure. If you want to avoid using chemicals on your deck, a mixture of vinegar and water, a scrubbing brush, and some hard scrubbing should remove dirt and mould.
Once the deck is cleaned, a new coat of varnish or oil can be applied. Products such as Cabot’s Aquadeck or Dryden Wood Oil can be used for this. If you would like to introduce a bit of colour to your deck, Resene’s Woodsman range, which comes in a variety of colours, could be used.
In some instances it is possible to re-stain a timber deck that has been stained previously. To assess whether this is possible, sprinkle some droplets of water on to the deck and wait a few minutes. If the water is absorbed, a new coat can be applied. If the water remains on the surface, the deck will need to be sanded down first.
The stain or oil should be applied with a bristle brush or foam brush. The stain or oil should be brushed on at the same direction of the wood grain to ensure full coverage. Make sure you wait until the stain or oil is fully dried before applying the subsequent coats, and be sure to read and follow any safety instructions on the can before application.
You might be interested in reading: Outdoor covering options and prices.
This article by Joanna Mathers featured on page 41 in Issue 009 of Renovate Magazine. New Zealand's first and only magazine solely dedicated to home renovations.
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*All information is believed to be true at time of publishing and is subject to change.
The costs in this article reflect the prices at the time of publication. Learn more here about the importance of planning your project ahead to minimise industry disruptions.