When sourcing wood composite beams, you must prioritize structural integrity and material composition. Key specs include the Modulus of Elasticity (MOE) and Modulus of Rupture (MOR), which define load-bearing capacity. For WPC (Wood Plastic Composite), ensure a wood-to-polymer ratio (typically 60% wood fiber, 30% HDPE, 10% additives) that balances strength and weather resistance. For structural glulam, verify the adhesive type, ensuring it is Phenolic or Isocyanate-based for waterproof performance.