Laying Decking

• Seasoned decking boards should be spaced with a 4mm gap; unseasoned with a 2mm gap to allow for shrinkage (this may vary for larger board widths).
  
• Butt joints in boards should be staggered. (Refer to Figure 4 under Durability).
  
• Where fixing occurs other than at the ends of the board, nails should be staggered across the joist to avoid shrinkage cracks. (Refer to Figure 5 under Durability).
  
• Each board should be fixed at each joist with two nails which should be finished flush with the top of the boards (rather than punched) to prevent moisture being trapped. (Refer to Figure 5 under Durability).
  
• To obtain a tight fit at joints, a slight under-cut is recommended. (Refer to Figure 6 under Durability).
  
• To prevent splitting, nails should be kept a minimum of 12mm from edges and ends, and drilled nail holes should be 80% of the nail diameter. (Refer to Figure 6 under Durability).