Simpson Deck-Drive DCU Composite Screw in #10 x 2-3/4", Gray, Type 305 Stainless Steel is purpose-built for fastening composite and PVC deck boards with a clean, professional result. Engineered by Simpson for demanding outdoor decking installations - including environments exposed to chlorides such as coastal or poolside applications - this cap-head composite decking screw combines corrosion-resistant Type 305 stainless steel construction with innovative thread and point geometry that makes installation faster and cleaner. The color-matching gray painted head blends seamlessly with popular composite decking manufacturers' products, eliminating visible fastener heads for a more concealed finish.

Key Features

• Type 305 Stainless Steel material - delivers strong corrosion resistance for outdoor composite deck applications, making it especially well-suited for environments with chloride exposure such as coastal or pool-adjacent decking.
• Type-17 point - penetrates composite and PVC decking cleanly without pre-drilling, saving installation time and reducing surface damage.
• Inverted upper (Tri-Lobe) threads - engineered to clear excess composite material as the screw drives, ensuring a flush, clean, and secure installation with no mushrooming around the fastener head.
• Cap head style with 0.230 in. head diameter - provides a low-profile bearing surface that seats flush against composite board surfaces for a tidy, professional appearance.
• T20 6-Lobe drive type - maximizes torque transfer and reduces driver bit cam-out, resulting in greater control and less surface marring during installation.
• Gray color-matching painted head - blends with popular composite decking products for a more concealed, professional finish that does not draw attention to the fastener.
• 2-3/4 in. length in #10 screw size - sized for reliable holding power when fastening composite deck boards to wood framing, providing the penetration depth needed for a secure connection.

Why This Product

• Designed specifically for composite and PVC decking - the Type-17 point and inverted Tri-Lobe threads work together to penetrate and fasten composite boards cleanly, eliminating the need to mix and match different screws for different decking types.
• Type 305 stainless steel construction makes this screw a reliable choice for decking projects in chloride-rich environments - such as seaside or poolside installations - where standard steel fasteners would corrode prematurely.
• The gray painted cap head is engineered to match popular composite decking colors, so the finished deck surface looks polished and consistent without visible fastener hardware standing out.
• The T20 6-Lobe drive reduces cam-out and wasted effort during installation, which translates to faster, more consistent results across large decking projects.

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #10
• Length (in.): 2 3/4
• Color: Gray
• Material: Type 305 Stainless Steel
• Finish: Type 305 Stainless Steel
• Head Type: Cap Head
• Head Diameter (in.): 0.230
• Drive Type: T20 6-Lobe
• Thread Type: Tri-Lobe Threads
• Point Type: Type-17 Point

Available Pack Options

• DCU234P305GR: 350 Pk - includes 1 driver bit included
• DCU234MB305GR: 1750 Pk - includes 2 driver bits included

Approved Applications

• Decks - Deck Boards Composite

Frequently Asked Questions

Why are these screws recommended for composite and PVC decking over standard wood screws?

The Deck-Drive DCU is engineered specifically for composite and PVC decking applications. The Type-17 point penetrates composite material cleanly, while the inverted Tri-Lobe upper threads clear excess material during installation to produce a flush, secure result. Standard wood screws do not have these design features and can cause composite decking to mushroom or crack around the fastener head.

What makes this screw suitable for environments with chlorides?

This screw is constructed from Type 305 stainless steel, which is selected specifically for its corrosion resistance in environments exposed to chlorides - such as coastal areas, poolside decks, and similar high-moisture or salt-exposed settings. The Type 305 stainless steel material resists the oxidation and degradation that would affect standard steel or lower-grade stainless fasteners in those conditions.

Will the gray painted head match my composite decking?

The gray painted cap head is designed to blend with popular composite decking manufacturers' products. For specific color compatibility, refer to the Composite-Decking Color Cross-Reference chart available in the Downloads and Resources section below.

What driver bit do I need to install this screw?

This screw uses a T20 6-Lobe drive. The compatible replacement driver bit is listed in the Related Products section below. Using the correct bit ensures maximum torque transfer and minimizes cam-out during installation.

Downloads and Resources

• Composite-Decking Color Cross-Reference chart

Related Products

• BIT20T-2-R2 - Compatible T20 6-Lobe driver bit
• Deck-Drive Screw Plug Solution - Compatible color-matching DCU screw plugs