#17 x 16in Construction Lag Screw Torx Drive - Heavy Duty

In this review the reviewer looks at the #17 x 16in Construction Lag Screw, a heavy duty exterior coated lag screw aimed at builders who need strength and corrosion resistance. The bottom line: this pack of 25 lag screws is for contractors and serious DIYers who want a fast-starting, high-strength fastener that can pull 4x6s tight and withstand harsh exterior conditions. The review focus is on build quality, corrosion performance and real-world ease of use when joining treated lumber and deck structures.

Key Features

• Construction grade dimensions: The ~5/16in thread diameter and 16in length provide deep engagement for large timbers, giving confidence when attaching beams or ledger boards.
• Heat treated steel: Manufactured from high quality heat treated steel to deliver improved shear and compression performance over common lag bolts.
• Exterior triple coating: Triple coated finish passed a 1200 hour salt spray test, which helps resist corrosion on exterior projects and ACQ treated lumber.
• Type 17 notched point: The Type 17 extra sharp point starts quickly without walking, reducing the need for pre-drilling in many applications.
• Torx/Star drive: The high performance Torx drive lets users apply greater torque with less cam-out for faster installation.

Who It's For

These lag screws are best for professional builders, deck contractors and experienced DIYers installing heavy timber connections, ledger attachments and structural exterior framing. The long 16in length and robust thread diameter make them particularly suited to projects that require deep penetration and strong draw-down of large members like 4x6s and beams.

Those who primarily do light indoor work or only need short fasteners should look elsewhere for smaller or cheaper options; these screws are optimized for exterior structural performance and may be more than required for trim or small indoor projects.

Pros & Cons

Pros

• Excellent corrosion resistance backed by a 1200 hour salt spray test, so they hold up well on exterior projects.
• Strong, heat treated steel construction gives better shear and compression strength than common lag bolts.
• Type 17 point and Torx drive make starts quick and reduce walking, speeding installation.
• Length and thread profile allow tight pull-down of 4x6 lumber and other large timbers.

Cons

• The 16in length and heavy construction are overkill for small interior tasks, making them a less economical choice for light work.
• Because of the size, installation requires appropriate tools and clearance and may be slower than using shorter fasteners.

Specifications

Our Verdict

For anyone building decks, heavy timber frames or exterior structures the #17 x 16in construction lag screw is a practical, cost-effective choice because it pairs heat treated strength with proven corrosion resistance and a fast-starting point. Its size and finish make it especially good value when you need reliable long-term performance on treated lumber.

Frequently Asked Questions

Are these safe for use with treated lumber?
Yes, the triple coating and corrosion testing make them compatible with ACQ treated lumber for exterior applications.

Do these require pre-drilling?
The Type 17 notched point reduces the need for pre-drilling in many situations, but pre-drilling may still be recommended for very dense hardwoods or exact alignment.

What tools are needed?
A Torx/Star driver bit and a powerful drill or impact driver are recommended to drive these 16in screws efficiently and safely.