Outdoor Decking

South American Solid Hard Wood Decking


About the Species

PATAGONIAN  WALNUT is grown in Paraguay where the DECKING is also manufactured.

After manufacturing, the DECKING is left to dry (Air Dry to about 20 – 25% moisture content) and this is how it is shipped to our customers.

The species is amongst the hardest and most dense known. It offers superior durability and rot/decay resistance that even pressure treated products cannot surpass.

General Characteristics: Heartwood olive brown to blackish, often with lighter or darker striping; sharply demarcated from the whitish or yellowish sapwood. Texture fine to medium; luster low to medium; grain straight to very irregular; rather oily looking; without distinctive odor or taste.

Durability: Heartwood is very resistant to attack by decay fungi and termites


On arrival at site, the DECKING should be allowed to acclimatize and stabilize to the environment’s humidity levels before installation and should be stored out of direct sunlight.  In doing so you will reduce the spacing between boards due to shrinkage after installation.  If the wood has not been allowed to pre-shrink in width prior to installation, gaps between boards may develop that are wider than the original desired spacing.

End Sealing

Moisture is most readily absorbed through the end grain that is exposed with each cut.  For this reason, the ends of the boards are the areas most prone to checking and splitting.  To help reduce end checks a clear aqueous wax -based emulsion is recommended to seal all ends immediately, this will reduce end checking.

Board Spacing

It is important to remember that the wood will expand and contract with changes in air moisture.  The majority of movement will be in the width.  So make sure to leave enough space between the boards side to side to provide drainage and to avoid buckling as the wood expands.  For SOUTH AMERICAN SPECIES we recommend a spacing of between 3mm to 5mm between boards side by side.  This will allow for proper air circulation between boards but also minimizes gap width after the natural seasoning of the lumber takes place.

Construction Site

Allow for ground side ventilation in the design as proper air circulation through the structure is necessary for long term stability. When installing there should be a minimum 3 to 5mm gap between deck boards to aid in air circulation and drainage. When fully acclimated some minimal shrinkage can be expected.


The DECKING can be worked with conventional carbide tipped saw blades and drill bits. Pre-drill board ends when using all types of fasteners to reduce splitting. Pre-drill and countersink when using screws.


We recommend that all decks be sealed upon installation to assist in the acclimation process and to reduce the potential for surface checking.

Before the deck can be finished, you must make sure that it is clean, dry and free of mildew.  Best to pre-wash to remove all dirt and to wait until the DECKING is thoroughly dry (usually 48 hours) before applying any coat.  The options are:

  • Uncoated – The DECKING can be left uncoated and over time will weather to a silver/gray colour.
  • Deck Sealers Water Repellent – – only use this if you want the DECKING to weather to gray
  • Deck Sealers Pigmented (UV Protection) – this offers greater performance and longer durability. Needs to be reapplied periodically but over time the wood fibers will become fully protected and maintenance will become less frequent.  This helps to preserve the beauty and colour of the DECKING, as well as minimize the appearance of surface checking and reduce colour fading,  We recommend using an high quality penetrating oil-based sealer with UV inhibitors.  Always follow coating manufacturers directions for the best results and also TEST a sample before applying.