Decking

Our typical species for hardwood decking are: Grey and Red Iron Bark, Turpentine, Spotted Gum, Tallowwood and Grey Bark. Our decking timbers are kiln dried to between 9 and 14% moisture to meet New Zealands environment requirements. Our Australian hardwoods are all class 1 timbers (40 year plus natural durability) with excellent durability.

The majority of New Zealand’s hardwood decking industry utilises tropical rain forest timbers such as Kwila, Garapa, Vitex, and Purple Heart to name a few. “50% of the worlds tropical rainforest have been devastated in the last 40 years” – quoted by David Attenborough so the next time you look to purchase some hardwood decking, instead of being price conscious, maybe you can be environmentally conscious instead.

If you have the time, this article is worth a read which talks about the likes of Kwila and how unsustainable this hardwood decking product can be: https://thespinoff.co.nz/society/22-02-2019/how-nz-decking-timber-choices-compound-a-human-rights-crisis-in-west-papua/

It is very important to have ventilation- free-air circulation under the decking which will help to minimise cupping and warping. This allows moisture content levels between top face and the underside of boards to be reduced and extends the life and performance of your hardwood deck.

We recommend that your substructure for the deck should have at least 250mm – 300mm clearance from the ground in conjunction with suitable board spacing. This will allow for adequate ventilation. Machine coating of all 4 sides of the decking is also highly recommended.

For Fijian Mahogany, a damp proof course membrane is required for any timber deck closer than one metre to the ground.

• Joist spacing 450mm recommended for 20mm thick decking.
• Screws should penetrate at least 35mm-40mm into the joists to achieve good bearing. Nails or screws can be used.
• Pre-drilling is a must for nails whilst our Wurth 50mm self tapping screws are an excellent option except for when less than 60mm from the edge of the decking board where pre-drilling is advised.
• Our Australian hardwood decking should be spaced with a minimum 8mm gap between decking boards. This will allow for some expansion & contraction as the decking boards acclimatise as well as allowing for drainage of surface water and good air circulation.
• Cross flow ventilation is also required to ensure that the decking has adequate airflow to vent the boards from all sides.

Note: Around New Zealand there are different climatic zones and timber will always react to the environment it is going into. Please contact if you have any specific questions about your decking project and the region in New Zealand you are building.

To help minimise any surface checking, cupping and maintain our hardwoods incredible grain / aesthetic look, we recommend coating the decking boards on all four sides with Intergrains Natures Oil, a penetrating oil by Dulux prior to installation. We offer this as a machine coat straight from our mill in Brisbane so you can simply lay the timber once it is received onsite. After 5-6 weeks of weathering, an additional face coat following installation is also recommended.

Please Note: When cutting our decking timbers, oiling the ends of the board will help to minimise splitting, cupping and checking on the ends of the boards – especially on 45 degree mitre cuts. It is preferable that once oiled these corners are also screwed together.

We strongly recommend use of Wurths self-trapping (pre-drilling is recommended) stainless steel screws (copper colour screw available also) for fixing your decking to the sub frame. We recommend 50-60mm long screws through our 20mm decking board, two screws per joist.

Australian Hardwood Decks should ideally be cleaned with a firm brush at least once a year to clean gaps between your decking boards and remove dirt and grime. This will also help to remove any surface mould (caused when moisture in the timber is 20% or greater) which can be a nasty slip hazard in wet weather. You can use a high pressure hose but please ensure this is on a low pressure setting to ensure you do not damage the wood grain/fibre of the timber.

Deck Recoating: Removing dirt and mould prior to coating is key before recoating with oil. There are many deck cleaning products out there but our preference are those offered by Dulux as we receive a 20% discount on all products and find these work the best. Please follow the manufacturer’s instructions when using.

Re-coating – How Often? This is a question we get all the time. The answer is, it really does depend on how much direct sunlight your deck receives and how much you will allow your deck to silver off. With New Zealand’s strong UV, if you want to keep your deck looking pristine then you will look to oil it once a year. Otherwise, once every 2-3 years will still keep you deck in good order.

Please Note: Always follow the manufacturer’s specification for re-coating. Again we recommend products by Dulux’s Intergrain Penetrating Oil Range.