Trex decking is the first wood composite lumber to receive a listing with BOCA and SBCCI (NER-508), and ICBO (ICBO ES ER-5747), the nation's three largest code listing agencies.

Structural Notes 

Trex decking is not designed to perform as a one-for-one structural replacement for wood in all applications.  It should not be used for primary load-bearing members such as posts, joists, beams or stringers.

In most residential decking installations, a span of 16" on center using a minimum of 3 joists will provide excellent results.