So when you install pressure treated, flat sawn, wood decking, do you face the bark side up (left in photo) or bark side down (right in photo)? Ask ten people and half will likely say ‘bark-side-up,’ a few will say ‘bark-side-down’ and the rest will shrug their shoulders. For some direction, we can turn to wood scientists – they actually study stuff like this.
But who cares and what do we hope to gain by orienting deck boards a particular way? The objectives for orienting the decking bark side up or down are to minimize cupping (which leaves raised edges for feet to catch on), reduce splitting (AKA ‘checking’), diminish the chance for rot and have fewer splinters.