Key Features
316 Stainless Build Type 316 stainless steel gives this composite decking screw severe-level corrosion resistance, which matters when the deck is exposed to chlorides or harsh outdoor conditions. Cleaner Composite Fastening The tri-lobe thread design, inverted upper threads, and cap head work together to reduce board damage, clear excess material, and help prevent mushrooming for a cleaner finished deck surface. Built for Volume This 1,750-pack of Simpson Strong-Tie Deck-Drive DCU COMPOSITE Screw fasteners is set up for big deck jobs, not patch work. You get the quantity needed to keep a crew moving without constantly opening new boxes.
Overview
The Simpson Strong-Tie Deck-Drive DCU COMPOSITE Screw, #10 x 2-3/4-in. T20, Type 316, 1750-Pack (DCU234MB316) is a composite decking screw built for fastening composite deck boards with a clean finished look and strong corrosion resistance. This is a composite decking screw designed for fastening composite decking boards. Model Number: DCU234MB316. If you are building a full deck and want a fastener that drives cleanly into composite material without beating up the board surface, this is the one this line is made for.
What matters here is not just the size, but how the screw behaves in the board. Simpson uses a tri-lobe thread design to reduce damage while driving, inverted upper threads to clear excess material, and a cap head to help prevent mushrooming. In real use, that means less material pushing up around the head and a cleaner-looking install across the whole deck surface. The Type-17 point is there for fast starts and easier penetration into composite decking, so you spend less time fighting the screw at the surface.
This specific version is a #10 x 2-3/4 in. hand-drive screw with a T20 6-lobe drive, cap head, and Type 316 stainless steel construction. The 316 stainless build is the big story for buyers working near salt air, pool environments, coastal areas, or anywhere chlorides are part of the jobsite conditions. Simpson specifically positions this material for severe-level corrosion resistance, which makes it a better fit than basic coated fasteners when long-term exposure is a real concern.
The head and thread design are geared toward finish quality as much as holding power. Composite decking can be unforgiving when the wrong screw lifts fibers, mushrooms the surface, or leaves a rough halo around the head. Here, the cap head keeps material from rising above the deck, while the inverted upper threads help clear it out as the screw seats. That combination is exactly why these are purpose-built deck screws rather than generic exterior screws with a fancy label.
From a jobsite practicality standpoint, this is also a volume-friendly pack. The box includes 1,750 screws, which Simpson notes is enough for approximately 500 sq. ft. of decking with framing at 16 in. on-center spacing. That makes this pack a better fit for full deck builds, production work, or contractors who want one consistent fastener across a large install. Tool Nut also lists (2) driver bits included, with replacement bit part number BIT20T-2-R2.
Compatibility is straightforward. The drive interface is T20 6-lobe, and Simpson notes that the 2-3/4 in. length is an approved fastener by Trex for Trex composite decking. Simpson also states this length is available collated for the Quik Drive system, which matters if you are standardizing around the DCU platform and planning higher-volume fastening workflows, even though this SKU itself is listed as a hand-drive screw.
Who should buy this? Deck builders, remodelers, contractors, and serious DIYers installing composite or PVC decking in demanding outdoor environments. If you are after painted heads to blend with board color, this exact SKU is unpainted, so appearance-sensitive installs may push you toward one of the color-matched versions in the DCU family. But if corrosion resistance is the priority and you want a purpose-built composite deck fastener in contractor quantity, this pack makes a lot of sense.
Drives Clean in Composite Decking
This is where a dedicated composite deck screw earns its keep. The screw is made to start fast, seat cleanly, and leave a smoother finished surface on composite boards.
- Tri-lobe thread design reduces damage to the composite board while driving
- Cap head helps prevent mushrooming and material from rising above the deck surface
Fast Starts, Less Fuss
The point and thread design are set up to get the screw moving into composite material without the rough entry you often get from a general-purpose fastener.
- Type-17 point penetrates composite decking with ease for fast starts
- Inverted upper threads clear excess material for a cleaner finish as the screw seats
Made for Harsh Outdoor Exposure
This specific DCU234MB316 version uses Type 316 stainless steel, which is the right move when the deck is going into a tougher environment and basic coating is not enough.
- Type 316 stainless steel construction for severe-level corrosion resistance
- Unpainted finish on this SKU
What’s in the Box
- (1,750) Simpson Strong-Tie DCU Composite Decking Screws, #10 x 2-3/4 in.
- (2) Driver bits
Replacement bit part number: BIT20T-2-R2.
Key Specifications
| Material | Type 316 Stainless Steel |
|---|---|
| Screw Size | #10 |
| Length | 2-3/4 in. |
| Head Diameter | 0.230 in. |
| Drive Type | T20 6-Lobe |
| Head Type | Cap Head |
| Thread Type | Tri-Lobe Threads |
| Point Type | Type-17 Point |
| Packaging Quantity | 1,750 |
| Color | Unpainted / None |
Compatibility
Drive Interface Uses a T20 6-lobe drive. Replacement bit part number is BIT20T-2-R2. Decking Material Designed for fastening composite decking boards. Simpson also states the Type 316 stainless version is suited for all types of composite and PVC decking. Approved Use The 2-3/4 in. length is listed by Simpson as an approved fastener for Trex composite decking. System Note This SKU is a hand-drive screw. Simpson notes the 2-3/4 in. length is also available collated for the Quik Drive system.
Built For
Deck Building Composite Decking PVC Decking Outdoor Construction Remodeling General Contracting Deck Installers Serious DIY / Hobbyist
Pro Tip
If your job involves roof sleeper assemblies, do not assume this 2-3/4 in. screw is the right length just because it is in the same DCU family. Simpson specifically calls for the 2 in. DCU screw for sleeper assemblies and says it should penetrate at least 1 in. into the wood sleeper without going through it.
Tool Nut’s Take
Tool Nut’s Take
Simpson Strong-Tie Deck-Drive DCU COMPOSITE Screw for serious deck work
This is the buy when you want a purpose-built composite deck screw with real corrosion resistance and enough quantity to handle a full build.
- Who it’s for: Contractors, deck builders, and homeowners doing a substantial composite or PVC decking project, especially in coastal or chloride-heavy environments.
- Why it stands out: The Type 316 stainless body is the headline, but the real day-to-day benefit is how the tri-lobe threads, inverted upper threads, Type-17 point, and cap head work together for cleaner fastening in composite boards.
- Worth knowing: This exact DCU234MB316 pack is unpainted and hand-drive. If head color match matters, the DCU line has painted options, but if corrosion resistance is your top concern, this unpainted 316 version is a smart pick.
Common Questions
- Is this screw approved for Trex decking? Yes. Simpson states the 2-3/4 in. length is an approved fastener for Trex composite decking.
- What drive type does it use? It uses a T20 6-lobe drive.
- Is this painted to match deck boards? No. This DCU234MB316 version is unpainted.
- How much decking will this box cover? Simpson notes that 1,750 screws install approximately 500 sq. ft. of decking with framing at 16 in. on-center spacing.
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