Simpson Strong-Drive MTH Wood Underlayment Screw (Collated) - #7 x 1-1/4 in. Gray Phosphate, 2500-Pack is engineered by Simpson for fast and secure underlayment-to-subfloor installations. Unlike nails, this collated screw features an intricate high-low thread pattern that holds underlayment tight to the subfloor, resisting pull-out and eliminating the squeaking that loose underlayment causes over time. The compact trim head countersinks cleanly, leaving a flush surface that prevents floor coverings from settling into recess voids - making it a reliable choice for underlayment and backer board applications.

Key Features

• Trim head with nibs - countersinks easily and sits flush with the surface so floor coverings lay flat without telegraphing fastener locations
• #2 square drive - delivers positive bit engagement and reduces cam-out during high-volume installation
• Driver bit included in each box - provides a ready-to-use setup right out of the box, saving time on the job
• High-low threads - the alternating thread pattern grips underlayment firmly to the subfloor, preventing pull-out and the squeaks that result from movement
• Sharp point - starts fast without pre-drilling, speeding up installation across large floor areas
• Curved collation - compatible with auto-feed screw driving systems for rapid, consistent fastener placement
• Gray phosphate coating - suited for dry, low-corrosion interior environments where this level of corrosion resistance meets the demands of the application

Why This Product

• Engineered to prevent squeaky floors - the high-low thread pattern is specifically designed to hold underlayment tight against the subfloor, addressing one of the most common long-term complaints in flooring installations before it starts
• Collated for professional-speed installation - curved collation allows these screws to work with the Simpson Strong-Tie Quik Drive PRO200SG2 auto-feed screw driving system, dramatically reducing installation time on large underlayment or backer board projects
• Clean, flush finish without extra work - the trim head with nibs countersinks without damaging the underlayment surface, so floor coverings go down smoothly over a flat, stable substrate
• A complete solution in every box - each box includes a #2 square drive bit so installers have everything needed to get started immediately, with no separate accessory purchase required

Specifications

• Model Number: MTH114S
• Screw Size: #7
• Length: 1-1/4 in.
• Head Type: Trim Head
• Drive Type: #2 Square
• Thread Type: High/Low Threads
• Point Type: Sharp Point
• Collation Type: Curved
• Coating/Finish: Gray Phosphate Coating
• Compatible Tool: Simpson Strong-Tie Quik Drive PRO200SG2 auto-feed screw driving system or attachment
• Quantity: 2,500

Approved Applications

• Underlayment / Backer board

What's Included

• 2,500 Simpson Strong-Drive MTH Wood Underlayment Screws (#7 x 1-1/4 in.)
• #2 square drive bit (model BIT2S)

Frequently Asked Questions

What is the purpose of the high-low thread pattern on the MTH114S screw?

The high-low thread pattern is specifically designed to prevent squeaking by holding underlayment tight to the subfloor, thereby preventing pull-out and maintaining a secure, stable installation over time.

What tool is compatible with these collated underlayment screws?

The MTH114S installs with the Simpson Strong-Tie Quik Drive PRO200SG2 auto-feed screw driving system or attachment, enabling fast and consistent installation across large areas.

Is the gray phosphate coating suitable for all installation environments?

The gray phosphate coating is recommended for dry, low-corrosion environments. It is not intended for use in wet, humid, or high-corrosion conditions.

Does the MTH114S trim head affect the finished floor surface?

Yes - the compact trim head with nibs is designed for easy countersinking, providing a flush surface that prevents floor coverings from settling into countersink recesses for a smooth, professional finish.

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