SDW Strong-Drive® Structural Wood Screws
The Simpson Strong-Tie® Strong-Drive® SDW wood screw is a 0.22" diameter, high-strength structural wood screw specifically designed for fastening
multi-ply wood members, such as joining plated trusses, engineered-lumber products and solid-sawn lumber.
The SDW installs easily with no pre-drilling and is available in optimized lengths for fastening 2-, 3- and 4-ply trusses or 1 3/4" engineered lumber, such as structural composite lumber (SCL).
With the SDW screw, multi-ply trusses and beams can be fastened from one side without requiring the lifting and flipping of heavy assemblies. The large, flush head eases the handling of assembled girders and simplifies the installation of finishes or structural connectors. Each SDW head is stamped with the Simpson Strong-Tie “No Equal” sign and the fastener length for easy identification after installation.
SDW Strong-Drive Screws Now Code-Listed!
The Strong-Drive SDW series of structural wood screws are now code listed and complies with the 2006 and 2009 IBC and IRC (see code report IAPMO ES ER-192).
Strong-Drive® SDW Structural Wood Screws Provide An Easy-to-Use, Cost-Effective Solution
- Low-profile head makes stacking and sliding members easier and allows installation of hardware and finishes to be virtually flush
- Higher shear values than competitive products enable wider screw spacing, saving time and money
- Patented 4CUT™ tip has a square core and serrated threads to provide fast starts, reduce installation torque and make driving easier with no pre-drilling
- Bold thread design firmly cinches plies together for consistent installation
- Deep, 6-lobe T-40 recess reduces cam-out, making driving easier
- Under head nibs provide the installer with greater installation control when the head meets the wood surface
- Optimal screw lengths provide maximum penetration while preventing the tip from protruding out the back of the member
- Ability to penetrate multi-ply trusses from only one side eliminates the need for truss flipping
- Available in retail, mini-bulk and bulk quantities to suit user needs
Heat-treated carbon steel
Black E-coat™
WARNING: Industry studies show that hardened fasteners can experience performance problems in wet or corrosive environments. Accordingly, the SDW wood screws should only be used in dry, interior and non-corrosive environments.
- SDW screws install best with a low-speed 1/2" drill and a T-40 6-lobe bit. The matched bit included with the screws is recommended for best results.
- No pre-drilling is typically required. SDW screws may be installed through metal truss plates as approved by the Truss Designer, provided the requirements of ANSI/TPI 1-2007 Section 8.9.2 are met (pre-drilling required through the plate using a maximum of 5/32" bit).
- Screw heads that are countersunk flush to the wood surface are acceptable if the screw has not spun out.
- Individual screw locations may be adjusted up to 3" to avoid conflicts with other hardware or to avoid lumber defects.
- Single-fastener shear loads for Tables 1-4, and withdrawal loads in this section, are based on testing per ICC-ES AC233. Allowable withdrawal load for DF/SP/SCL is 200 pounds per inch (lbs./in.) and for SPF/HF withdrawal is 150 lbs/in. Total allowable withdrawal load is based on actual thread penetration into the main member.
- Allowable loads in tables are shown at the load duration factor of CD = 1.00 and shall be multiplied by all applicable adjustment factors per the NDS. Loads may be increased for load duration per the building code up to a CD of 1.6.
- Minimum fastener spacing requirements: 6" end distance, 17/16" edge distance, 5/8" between staggered rows of fasteners, 4" between non-staggered rows of fasteners and 6" between fasteners in a row. Note exceptions in Table 5.
- Maximum fastener spacing is recommended to not exceed 24" on-center except as approved by a qualified Designer.
- For structural composite lumber (SCL = LVL, PSL or LSL) loads, assume an equivalent Specific Gravity of 0.50 or higher.
- Tabular loads on this web page are based on the capacity of the Simpson Strong-Tie® SDW22 fasteners. The capacity of the multi-ply assembly must be checked by a qualified Designer.
Loaded on Head Side
(3-ply assembly shown –
other configurations similar)
Table 1 – Single Fastener Shear Loads for Solid Sawn and 2x Truss Loaded on Head Side
- For minimum penetration into main member of 1 1/8", use 235 lbs. for DF/SP and 210 lbs. for SPF/HF.
Loaded on Tip Side
(3-ply assembly shown –
other configurations similar)
Table 2 – Single Fastener Shear Loads for Solid Sawn and 2x Truss Loaded on Tip Side
- For minimum penetration into main member of 1 1/8", use 235 lbs. for DF/SP and 210 lbs. for SPF/HF.
Loaded on Head Side
(3-ply assembly shown –
other configurations similar)
Table 3 – Single Fastener Shear Loads for LVL, PSL and LSL Loaded on Head Side
- For minimum penetration into main member of 1 1/2", use 300 lbs.
Loaded on Tip Side
(3-ply assembly shown –
other configurations similar)
Table 4 – Single Fastener Shear Loads for LVL, PSL and LSL Loaded on Tip Side
- For minimum penetration into main member of 1 1/2", use 300 lbs.
Table 5 – Single Fastener Shear Loads for Two-Ply
3x2/4x2 Parallel-Chord Trusses Loaded on Either Side
SDW Screw Position in 2-Ply 4x2 Truss
(2-ply 3x2 similar)
Concentrated Load
Uniform Load
- To transfer uniform loads applied to simply supported spans on assembly top chord:
- Space screws as required to transfer half the load into the supporting truss.
- Minimum screw spacing shall be 4" o.c.
- To transfer concentrated loads applied to simply supported spans on an assembly top chord or vertical web:
- Concentrated loads must be applied at the panel joints.
- Screws to be installed within 12" of the concentrated load on top-chord assembly
- Gap between the trusses shall not exceed 1/8" o.c.
- Floor sheathing shall be screwed or nailed to each top-chord ply. (Fastener spacing per the applicable Code requirements, or 12" o.c.)
- SDW screws shall not be installed in areas where lumber wane exceeds 1/4".
- Hangers on skewed girders:
- Hanger loads not exceeding 34" o.c. on a skewed girder (resulting from uniformly spaced joists up to 24" o.c.) may be converted to a uniform load.
- For girders with hanger load spacing in excess of 34" o.c. the loads shall be considered as concentrated loads at the applicable locations.
- Other configurations acceptable as long as approved by Truss Designer.
Table 6 – Sideloaded Multi-Ply Assemblies – Allowable Uniform Load Applied to Either Outside Member
Assembly A-W
Assembly B-W
Assembly C-W
Assembly F-W
Spacing Requirements 
- Each ply is assumed to carry same proportion of load.
- Loads may be applied to the head side and tip side concurrently provided neither published allowable load is exceeded. (Example: a 3-ply DF assembly with a head side load of 1300 plf and tip side load of 900 plf may be fastened together with 3 rows of SDW @ 16" o.c.)
- When hangers are installed on tip side, hanger face fasteners must be a minimum of 3" long.
- Tables are based on Main Member Penetration as noted in Tables 1 and 2.
- Hanger load spacing on the multi-ply assembly should not exceed 24" o.c. Exception: On a skewed girder, hanger loads up to 34" o.c. (resulting from joists uniformly spaced up to 24" o.c.) may be converted to a uniform load..
Table 7 – Sideloaded Multi-Ply LVL, PSL and LSL Assemblies – Allowable Uniform Load Applied to Either Outside Member
- Each ply is assumed to carry same proportion of load.
- Loads may be applied to the head side and tip side concurrently provided neither published allowable load is exceeded. (Example: a 3-ply assembly with a head side load of 1300 plf and tip side load of 1000 plf may be fastened together with 3 rows of SDW @ 16" o.c.)
- When hangers are installed on tip side, hanger face fasteners must be a minimum of 3" long.
- Tables are based on Main Member Penetration as noted in Tables 3 and 4.
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