Grip-Rite Hex Head Structural Screws are engineered to replace lag screws in load-bearing exterior wood construction. The exclusive dual drive power head combines a hex washer with a star drive recess, so the screw can be driven with the 3/8" hex driver included in the package or with a T-25 star bit. A Type 17 point removes the need to pre-drill pilot holes in wood species with a specific gravity of 0.55 or less, and the PrimeGuard Plus coating - a layer of zinc under a proprietary black outer coating - is approved for use in treated lumber.

• Size: 3/8" x 12" (12" overall length, 3-7/8" thread length)
• Dual drive hex washer head, 0.571" head diameter, T-25 star recess; 3/8" hex driver included in the package
• Type 17 point - ESR-3933 permits installation without predrilling in wood species with an assigned specific gravity of 0.55 or less
• Coarse thread, partially threaded with a reamer knurl between the thread and the smooth shank
• Carbon steel, hardened after forming, PrimeGuard Plus coating; color black
• Evaluated for use in ACQ-D treated lumber to 0.40 pcf retention as an alternative to the hot-dip galvanized fasteners prescribed in IBC Section 2304.10.6
• ICC-ES ESR-3933: allowable steel strength 6,315 lbf tension / 3,255 lbf shear, specified bending yield strength 230,000 psi
• Grip-Rite's lag screw replacement guide lists the 3/8" hex head as a replacement for 1/4", 5/16", 3/8", 7/16", 1/2" and 5/8" lag screws
• 3-digit ICC reference code HET stamped into the head for spec checking (H = hex washer head, E = 3/8, T = 12")
• Manufacturer part: GRSSHW381220
• Pack: 20 screws per box

Applications: Wood-to-wood structural connections in load-bearing exterior construction, designed under the IBC (or under the IRC where an engineered design is submitted per IRC R301.1.3). Grip-Rite's multi-ply beam evaluation (TER 2204-02) covers 3/8" screws up to 6" long, so this length sits outside those published details; design it from ESR-3933.

Installation: ESR-3933 requires screw penetration into the main member of at least 6 times the major thread diameter, which is 0.311" on this size. Section 4.2 also requires the screws be driven with star drive bits, perpendicular to the face of the side member, with the underside of the head bearing on the wood and without overdriving. Corrosion resistance is evaluated for treated wood in dry-service conditions and for freshwater exposure only - it does not cover saltwater exposure.