Ventilation and Spacing Essentials

Mahogany hardwood deckWhen building your brand new KAYU Hardwood Deck, it’s important to remember some key factors.  Hardwoods are a natural wood product and will expand in rainy, humid weather and contract in hot, dry weather.  If your deck is installed without proper airflow and spacing to allow for expansion and contraction you will inevitably face some issues down the road.  Below are a few installation tips:

  • Please follow your local building codes
  • Keep all decking materials dry, clean and out of direct sunlight prior to finishing and installing
  • If you wish to apply a finish/sealer to your deck, you must stain all four sides of your deck boards with a penetrating finish prior to installation.  Staining only one side can lead to uneven moisture content and increase the likelihood of cupping.
  • Allow adequate ventilation.  Install with a minimum ground clearance of 18″ with well ventilated airflow on at least 2 sides of the deck (at least 50% unrestricted airflow)
  • If less than 18″ ground clearance is necessary, we recommend using 5/4 X 4 deck boards.
  • Create a slope for drainage so there is no chance of standing water under your deck.
  • 5/4 X 6 and 5/4 X 4 KAYU Batu can be spanned up to 24″ on center, but recommend 16″ for an increasingly stronger deck.  We recommend spanning 1 X 4 and 1 X 6 16″ on center.  For other KAYU decking products allowable spans please contact KAYU directly or speak with your builder.
  • Adequate spacing is extremely important.  Please space your 6″ deck boards at least 1/4″ from side to side and 4″ decking at least 3/16″ from side to side.  Allow 1/4″ spacing from any structures.  (In wetter locations, we insist on a minimum gap of 5/16” for 6” decking and a minimum of ¼” for 4”.)
  •  Ends can be trimmed and butt tightly.
  • Since KAYU hardwoods are so dense, all material must be pre-drilled.  We recommend stainless steel screwsDo not use hidden clip fasteners!  The Kreg Deck Jig is a concealed fastener option we do recommend as it gives the option of 1/4″ or 5/16″ spacing between each board.
  • Please use proper safety equipment such as dust masks and safety glasses.

For additional information on installation, contact your KAYU or your local KAYU distributor.



KAYU hardwood decking products are carefully selected and inspected to ensure the finest quality.  However, all natural wood is subject to expansion and contraction as the moisture in the environment surrounding the wood changes. Shrinkage, expansion, checking, slight cupping and other movement are normal occurrences in all hardwood decking.  Natural wood products are subject to variances in color, grain, density and performance

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