Strong-Drive® SDWS TIMBER Screw (Exterior Grade) 

SDWS Timber Screw (Exterior Grade) — Allowable Shear Loads — Douglas Fir–Larch and Southern Pine Lumber

See footnotes below.

SDWS Timber Screw (Exterior Grade) — Allowable Shear Loads — Spruce-Pine-Fir and Hem-Fir Lumber

1. All applications are based on full penetration into the main member. Full penetration is the screw length minus the side member thickness.
2. Allowable loads are shown at the wood load duration factor of C_D = 1.0. Loads may be increased for load duration per the building code up to a C_D = 1.6. Tabulated values must be multiplied by all applicable adjustment factors per the NDS.
3. For minimum fastener spacing requirements for both side and main members, see the Spacing Requirements Figure and Table below.
4. For in-service moisture content greater than 19%, use C_M = 0.7.
5. Loads are based on installation into the side grain of the wood with the screw axis perpendicular to the face of the member.

SDWS Timber Screw (Exterior Grade) Spacing Requirements

1. For axial loading only, use the following minimum dimensions: end distance = 3 1/4", edge distance = 1 3/8", spacing parallel to grain = 2 1/4", spacing perpendicular to grain = 1 3/8".

SDWS Timber Screw (Exterior Grade) — Reference Allowable Withdrawal Loads — Douglas Fir–Larch, Southern Pine, Spruce-Pine-Fir and Hem-Fir Lumber

1. The tabulated reference withdrawal design value, W, is in pounds per inch of the thread penetration into the side grain of the main member.
2. The tabulated reference withdrawal design value, W_Max, is in pounds where the entire thread length must penetrate into the side grain of the main member.
3. The tabulated reference withdrawal design values, W and W_max, are shown at a C_D = 1.6. For end-grain withdrawal, C_eg = 0.65. Tabulated values must be multiplied by all applicable adjustment factors from the NDS as referenced in the IBC or IRC.
4. Embedded thread length is that portion held in the main member including the screw tip.
5. Values are based on the lesser of withdrawal from the main member or pull-through of a 1 1/2" side member.
6. For in-service moisture content greater than 19%, use C_M = 0.7.

SDWS Timber Screw (Exterior Grade) — 2021 and 2018 IRC Compliant Spacing for a Sawn Lumber Ledger to Rim Board with One or Two Layers of 5/8" Gypsum Board

1. Sawn rim board shall be spruce-pine-fir, hem-fir, Douglas fir-larch, or southern pine species. Ledger shall be hem-fir, Douglas fir-larch, or southern pine species.
2. Fastener spacings are based on the lesser of single fastener ICC-ES AC233 testing of the Strong-Drive SDWS screw with a safety factor of 5.0 or ledger assembly testing based on ICC-ES AC13 with a factor of safety of 5.0. Spacing does not include NDS wet service factor adjustment.
3. Multiple ledger plies shall be fastened together per code independent of the SDWS screws.
4. SDWS screw spacing values are equivalent to 2021 /2018 IRC Table R507.9.1.3(1) and 2012 /2015 IRC Table R507.2. The table also provides SDWS screw spacing for a wider range of materials commonly used for rim boards, and an alternate loading condition as required by some jurisdictions.
5. Screws shall be placed 1.5" to 2" from the top and bottom of the ledger or rim board with 3" minimum and 6" maximum vertical distance between fasteners with horizontal on-center spacing per the table. End screws shall be located 6" from the end and at 1.5" to 2" from the bottom of the ledger. For screws located at least 2" but less than 6" from the end, use 50% of the load per screw and 50% of the table spacing between the end screw and the adjacent screw, and for screws located between 2" and 4" from the end, predrill using a 5/32" drill bit.
6. The design installation permits a wood structural panel (WSP) interlayer in addition to one or two layers of gypsum board. If present, the WSP shall be a maximum of 1/2" thick, adjacent to the framing and fastened directly to the framing per the code.
7. Gypsum board must be attached as required per the building code.
8. Visit the Drawing Finder for additional ledger fastening detail sheets and load tables in DWG, PDF or DXF format.

See the Fastening Systems Technical Guide and refer to the Alphabetical Index for additional load tables, technical data and installation instructions for the Strong-Drive^® SDWS Timber screw.

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