Simpson Deck-Drive DCU Composite Screw in #10 x 2-3/4" with Type 305 Stainless Steel finish and Gray 05 color-matched painted head is engineered specifically for composite and PVC decking applications where a clean, professional appearance and long-term corrosion resistance are essential. Manufactured by Simpson, this cap-head fastener combines a Type-17 point for effortless penetration, inverted upper threads that clear excess material as they drive, and tri-lobe thread geometry for a secure, wobble-free hold - all wrapped in a corrosion-resistant 305 stainless steel construction that stands up to chloride-heavy environments such as coastal decks and poolside installations. The factory-applied Gray 05 painted head blends seamlessly with popular composite decking manufacturers' boards, delivering a concealed finish that elevates the overall look of any outdoor deck project.

Key Features

• Type 305 Stainless Steel material - provides superior corrosion resistance in environments exposed to chlorides, moisture, and salt air, making this screw well-suited for coastal, poolside, and high-humidity outdoor deck installations
• Type-17 Point - drills through composite and PVC decking without pre-drilling, speeding up installation and reducing labor on large deck projects
• Inverted upper threads - engineered to clear excess material as the screw seats, resulting in a clean, flush finish with no mushrooming or raised material around the fastener head
• Tri-Lobe thread design - creates a stronger, more secure grip in composite decking material compared to standard thread forms, reducing the risk of back-out over time
• T20 6-Lobe drive type - delivers increased torque transfer and reduced cam-out compared to traditional Phillips or square drives, meaning fewer stripped heads and faster, more consistent driving
• Cap Head with 0.230" head diameter - low-profile head sits flush and neat at the surface, contributing to both the professional appearance and structural integrity of the deck board connection
• Gray 05 color-matched painted head - blends with popular composite decking product lines for a more concealed, finished look that homeowners and contractors expect on premium deck builds
• #10 x 2-3/4" size - a commonly specified dimension for composite deck board attachment, offering the depth and holding power needed for a durable, long-lasting deck surface

Why This Product

• Engineered specifically for composite and PVC decking - unlike general-purpose screws, the DCU's Type-17 point and inverted upper threads are purpose-built to penetrate and seat cleanly in composite board material without splitting, mushrooming, or surface damage
• One screw for all composite decking types - eliminates the need to stock or match multiple fastener types across different composite and PVC board brands, streamlining the job site and reducing purchasing complexity
• Corrosion resistance rated for chloride environments - the Type 305 stainless steel construction is especially suited for decks near saltwater, pools, or areas with chemical exposure, where standard carbon steel or zinc-coated screws would corrode prematurely
• Color-matched head delivers a finished, professional result - the Gray 05 painted cap head blends with popular composite decking colors so fasteners remain visually inconspicuous, a key expectation on residential and commercial deck installations

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #10
• Length: 2-3/4 in.
• Head Diameter: 0.230 in.
• Head Type: Cap Head
• Drive Type: T20 6-Lobe
• Thread Type: Tri-Lobe Threads
• Point Type: Type-17 Point
• Material: Type 305 Stainless Steel
• Finish: Type 305 Stainless Steel
• Color: Gray 05
• Country of Origin: Vietnam

Available Pack Options

• DCU234P305GR05: 350 Pk - includes 1 driver bit included
• DCU234MB305GR05: 1750 Pk - includes 2 driver bits included

Approved Applications

• Decks - Deck Boards Composite

Frequently Asked Questions

Why is Type 305 Stainless Steel recommended for composite decking applications?

Type 305 Stainless Steel offers strong corrosion resistance against moisture and chlorides - making it especially suited for composite and PVC deck installations in coastal, poolside, or otherwise chemically active environments where standard steel fasteners would be prone to rust and premature failure. The DCU is engineered to provide lasting performance in these demanding outdoor conditions.

Do I need to pre-drill holes in composite decking before installing the DCU screw?

No pre-drilling is required. The DCU features a Type-17 point that is designed to penetrate composite and PVC decking directly, streamlining installation and saving time on the job. The inverted upper threads simultaneously clear excess material as the screw seats, leaving a clean finish at the board surface.

What driver bit do I need for the T20 6-Lobe drive on this screw?

This screw uses a T20 6-Lobe drive, which requires a compatible T20 bit. The recommended replacement bit is available - see the Related Products section below for the compatible driver bit and color-matching screw plug options.

Will the Gray 05 painted head match my composite deck boards?

The Gray 05 color is engineered to blend with popular composite decking manufacturers' board colors for a more concealed, finished appearance. For a complete color compatibility reference, download the Composite-Decking Color Cross-Reference chart linked in the Downloads and Resources section below.

Downloads and Resources

• Composite-Decking Color Cross-Reference chart

Related Products

• BIT20T-2-R2 - compatible T20 6-Lobe driver bit for installing DCU composite screws
• Deck-Drive Screw Plug Solution - color-matching screw plugs compatible with DCU screws for a fully concealed deck surface