SPAX® PowerLags® T-Star Washer Head Wood Lag Screws

Choose SPAX® PowerLags® T-Star Washer Head Wood Lag Screws. The low-profile, large diameter head design provides outstanding clamping force and improved aesthetics. Deep T-Star drive offers excellent bit engagement without requiring a “special” driver bit. Available in 1/4", 5/16”, and 3/8” diameters, and in lengths up to 10”. Buy SPAX T-Star Washer Head PowerLags and wood lag screws with HCR® high corrosion-resistant coating in bulk pails or in job-friendly package quantities (hex driver included) from wholesalers, dealers, and specialty distributors or retail hardware and home improvement stores near you.
Kick failures to the curb with American-made, rigorously tested wood-to-wood structural fasteners. Get the Full Story
Description
SPAX® T-Star Washer Head construction fasteners with HCR® coating are intended for wood-to-wood connections in exterior structural applications when attaching treated lumber components. These fasteners are designed with a low profile large diameter wafer head for applications requiring additional surface area under the head for superior pull-down force. Ideal for deck ledger attachment and multi-ply beam applications.
Material & Coating
Cold-rolled “carbon steel” wire heat treated to Grade 5 durability and plated with an HCR® (High Corrosion Resistance) double barrier coating. “HCR” is tested and recognized for use in ground contact pressure treated lumber for exterior, freshwater general construction applications (e.g. AWPA UC1-UC4A, UCFA).
Note: We are transitioning from green to black HCR during mid-June 2022 - New Color Matches Trending Exterior Projects!
SPAX® POWERLAGS®
SPAX PowerLags require no pre-drilling and drive faster and easier than conventional lags and other structural lag screws. We offer the largest selection of code-recognized structural wood-to-wood fasteners in the industry. Featuring SPAX patented thread technology and HCR high corrosion resistant coating, our T-Star washer head and PowerLags collection can be used for interior or exterior applications, including treated lumber.
- IRC / IBC Code Compliant DrJ TER No. 1912-07 Structural Fastener Properties
- DrJ Technical Evaluation Reports (TER No. 1711-01; Deck Ledger Attachment and TER No. 1802-03; Multi-Ply; Sawn lumber assemblies and engineered wood - LVL, PSL and LSL assemblies)
- Grade 5 durability
- No pre-drilling required (1/4" and 5/16")
Note: Lead hole of 11/64" (0.172") diameter is required for 3/8" - Patented thread serrations require up to 40% less driving torque to increase installation speed while helping prevent cracking in logs
- Built-on washer head designs eliminate the need and extra cost of a separate washer
- Fastener length stamp on the head provides convenient identification without measuring and aids on-site inspections
Choose SPAX PowerLags structural wood to wood screws with built-on washer design in a variety of screw styles, including Hex head, T-Star, and multiple coating options. Request a sample pack of SPAX PowerLags today and build strong connections on the job site. Need something stronger? Shop our PowerLags collection designed for timber frame and log home construction.

TYPICAL EXTERIOR APPLICATIONS
• Multi-ply LVL beam assembly
• Multi-ply girder truss assembly
• Exterior treated lumber pergolas & gazebos
• Landscaping timber
• Outdoor furniture
• Exterior fencing posts
• Exterior out buildings
• Deck ledger to residential band joist attachment
For CAD documents, please see Technical Documents.
Size | Drive/Bit Size | Thread | Available Pkg. Options | |||||||||
Retail Pax | Large Retail Pax | 1 lb. Box | 3 lb. Box | 5 lb. Box | Individual | Project Pax | Contractor Pax | Mini Pail | Bulk Pail | |||
1/4" x 2-1/2" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
1/4" x 3" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
1/4" x 3-1/2" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
1/4" x 4" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
1/4" x 4-1/2" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
1/4" x 5" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
1/4" x 6" | T-30 | Partial | 1+ | 12 | 50 | 500 | ||||||
5/16" x 3" | T-40 | Partial | 1+ | 12 | 50 | 250 | ||||||
5/16" x 3-1/2" | T-40 | Partial | 1+ | 12 | 50 | 250 | ||||||
5/16" x 4" | T-40 | Partial | 1+ | 12 | 50 | 250 | ||||||
5/16" x 4-1/2" | T-40 | Partial | 1+ | 12 | 50 | 250 | ||||||
5/16" x 5" | T-40 | Partial | 1+ | 12 | 50 | 250 | ||||||
5/16" x 6" | T-40 | Partial | 1+ | 12 | 50 | 250 | ||||||
5/16" x 6-3/4" | T-40 | Partial | 50 | 250 | ||||||||
5/16" x 8" | T-40 | Partial | 1+ | 12 | 50 | 150 | ||||||
5/16" x 10" | T-40 | Partial | 1+ | 12 | 50 | 150 | ||||||
5/16" x 12" | T-40 | Partial | 1+ | 50 | 150 | |||||||
3/8" x 5" | T-50 | Partial | 1+ | 12 | 25 | 150 | ||||||
3/8" x 6" | T-50 | Partial | 1+ | 12 | 25 | 150 | ||||||
3/8" x 8" | T-50 | Partial | 1+ | 150 | ||||||||
3/8" x 10" | T-50 | Partial | 1+ | 150 |




















