Simpson #8 x 1-5/8" Fiber-Cement Screw in Type 316 Stainless Steel is engineered by Simpson Strong-Tie specifically for attaching fiber-cement siding to wood framing and structural panels. Built from Type 316 stainless steel, this fastener resists corrosion in demanding outdoor and moisture-exposed environments, making it a reliable choice for long-term exterior cladding applications. The combination of a self-countersinking wafer head, aggressive Type-17 point, and full-length coarse threading means faster installation and a clean, flush finish without pre-drilling.

Key Features

• Ribbed wafer head with self-countersinking nibs - pulls flush into fiber-cement siding automatically, eliminating the need for pre-countersinking and producing a smooth, finished surface
• Type-17 point for fast starts - penetrates fiber-cement material quickly and cleanly, reducing splitting and speeding up installation on the job site
• Full-length coarse threading - maximizes grip into wood substrate beneath siding, delivering strong holding power and pull-through resistance
• Type 316 stainless steel construction - provides superior corrosion resistance compared to standard steel fasteners, suited for coastal, humid, and chemically exposed outdoor environments
• #2 square drive - reduces cam-out and driver slippage during installation, improving control and efficiency when driving into fiber-cement material
• 1-5/8" length - designed for blind-fastening fiber-cement lap siding to wood framing with adequate embedment depth

Why This Product

• Purpose-built for fiber-cement siding - the self-countersinking nibs and Type-17 point are specifically engineered for this dense material, unlike general-purpose wood screws that can crack or surface-pop fiber-cement boards
• Type 316 stainless steel delivers long-term durability in harsh conditions - ideal for coastal installations, high-humidity climates, and applications where standard zinc-plated fasteners would corrode prematurely
• The square drive design minimizes cam-out and stripped heads, helping installers maintain a steady pace without stopping to replace damaged bits or re-drive fasteners
• Engineered by Simpson Strong-Tie for use with fiber-cement lap siding to wood - a trusted fastener solution designed to meet the demands of structural exterior cladding installations

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #8
• Length: 1-5/8 in.
• Head Diameter: 0.395 in.
• Head Type: Ribbed Wafer Head
• Drive Type: #2 Square
• Thread Type: Coarse Threads
• Point Type: Type-17 Point
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Country of Origin: Taiwan

Available Pack Options

• T08C162WQ-RP75: 75 Pk - includes (1) #2 square-drive bit included
• T08C162WQC: 100 Pk
• T08C162WQ-RP300: 300 Pk - includes (1) #2 square-drive bit included
• T08C162WQM: 1000 Pk

Approved Applications

• Blind-fastening fiber-cement lap siding to wood framing
• Attaching fiber-cement siding to stressed-skin panels
• Exterior cladding installations in coastal and high-humidity environments where corrosion resistance is required

Frequently Asked Questions

What makes this screw suitable for fiber-cement siding specifically?

This screw features a wafer head with self-countersinking nibs that pulls flush into the dense surface of fiber-cement boards without pre-countersinking, along with a Type-17 point that starts fast and cleanly penetrates fiber-cement material. The full-length coarse threading then anchors securely into the wood substrate beneath for strong, lasting hold.

Why is Type 316 stainless steel used for this fastener?

Type 316 stainless steel offers excellent resistance to corrosion from moisture, salt air, and environmental exposure. This makes the screw well-suited for outdoor siding applications - particularly in coastal regions or climates where humidity and weather would degrade standard steel fasteners over time.

What drive bit is compatible with this screw?

This screw uses a #2 square drive. Simpson Strong-Tie references replacement bit model BIT2S-2-R2 as a compatible driver bit for this fastener.

Is this the correct length for fiber-cement lap siding installation?

Yes. The 1-5/8" length is specifically intended for blind-fastening fiber-cement lap siding to wood framing or structural panels. Simpson Strong-Tie also offers a 1-1/4" version designed for attaching fiber-cement siding to stressed-skin panels.

Note: Product dimensions and/or thread length may differ from picture. Please see the item description above for specifications.