Structural Grade Screws

When sourcing structural grade screws for code-compliant construction fasteners applications, request the current ICC-ES evaluation report number and publication date confirming allowable design values for the specific connection configurations required. The report should list tensile strength, shear strength, withdrawal resistance per species group, and any installation requirements such as pre-drilling or edge distance minimums. Cheng Hao maintains test documentation supporting structural grade screw performance and can provide certified material test reports confirming tensile strength and hardness values for each production lot, enabling quality verification at the point of receipt.

Structural grade screws provide documented shear resistance values derived from testing per ASTM D1761 or equivalent protocols in specific wood species and connection geometries. Standard construction fasteners lack published shear design values and cannot be used in code-compliant lateral load path designs. The shear resistance of structural grade screws depends on screw diameter, bending yield strength, embedment depth in the main member, and the combined bearing capacity of both connected members. Designers select screw size and spacing based on the design shear demand divided by the allowable single-fastener shear value from the ICC-ES report, applying appropriate load duration and wet service adjustment factors.

Allowable load values for structural grade screws as construction fasteners are based on specific installation conditions defined in the ICC-ES evaluation report. Critical parameters include minimum end and edge distances, minimum spacing between adjacent fasteners, and whether pre-drilling is required for dense or dry lumber. Deviating from these parameters reduces allowable loads and may void the evaluation report's applicability. Fastener orientation relative to grain direction also affects withdrawal resistance values. Contractors and inspectors should verify that installation patterns shown in shop drawings match the reference conditions in the evaluation report before approving structural grade screw connections for structural construction fasteners applications.