A decking screw is similar to a particle board screw but is generally coated with superior corrosion resistance -- or made out of stainless steel. Decking screws are always flat head (or Flat head Trim) with nibs and type 17. If it's flat and NO NIBS, it's not a deck screw. If it's got nibs but no 17 it still isn't a deck screw. The nibs (usually 4, but sometimes 6 or 8) located under the bearing surface under the head, on the angled sides of a countersunk type of head are to aid in cutting the top material to allow a flush, countersink finish without the need to countersink the hole first. Decking screws cannot have bugle heads. Bugle heads are always drywall screws. They come in square, Phillips, and combination drives.
(The nib is a bit hard to see in the pictures, sorry.)
You can trust Hardware Everywhere for all your deck screw and fastener needs. We are 3rd generation family owned and have been in the industry for over 65 years. Call 1-800-432-8979 or contact our experts for free deck screw advice. We’ll make sure you order the right fasteners for your decking project.