Simpson Strong-Drive® SDWS™ TIMBER Screw (Exterior Grade) (4" L - SDWS22400DBMB)

Simpson Strong-Tie Company

The Strong-Drive SDWS Timber screw is designed to provide an easy-to-install, high-strength alternative to through-bolting and traditional lag screws. This screw is ideal for the contractor and do-it-yourselfer alike. It is code listed in IAPMO UES ER-192 and meets 2018 and 2021 IRC® and IBC® code requirements for most common wood framing applications.

Key Features

  • Bold thread design provides superior holding power
  • SawTooth® point ensures fast starts, reduces installation torque and eliminates the need for predrilling in most applications
  • Underhead nibs allow for head to drive flush to surface with reduced splintering
  • Large washer head provides a large bearing area
  • Size identification on all SDWS screw heads
  • 6-lobe T40 drive provides positive engagement that makes the screw easy to drive and improves bit life (replacement driver bit — BIT40T-134-R2)
  • Double-barrier coating provides corrosion resistance equivalent to hot-dip galvanization, making it suitable for certain exterior and preservative-treated wood applications, as described in the evaluation report


  • Structural wood-to-wood/engineered including ledgers; mass timber connections including CLT wall-to-wall, floor-to-floor, surface splines and lap joints

Product Includes

  • Retail and mini-bulk packs include one 6-lobe, T40 driver bit; bulk packs include two driver bits (BIT40T-134-R2)

Patent Information

  • US Patents 9,523,383; 11,181,138

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