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FREQUENTLY ASKED QUESTIONS

Where can I buy SPAX^® product?

Please reference our Where to Buy page to locate the retail partner nearest you.

HOW MANY FASTENERS DO I NEED?

• Deck Board installation: Reference our decking fastener calculator
• Deck ledger: Reference SPAX deck ledger technical bulletin
• multi-ply assembly: Reference SPAX multi-ply technical bulletin
• truss / rafter connection: Reference SPAX truss / rafter to top plate connection technical bulletin

For all other applications we recommend referencing your local building code for guidance.

What length screw do I need?

While there is no perfect calculation to determine the proper length of screw to use, there is a general guideline you can use. For non-structural applications a good rule of thumb is to measure the thickness of the 1^st member (“what” you are attaching) and multiply it by 3. In the scenario where you are attaching ¾” OSB, you would use a 2-1/4” fastener (3/4” x 3 = 2-1/4”).

Multi-Material

WHY DO YOU CALL YOUR FASTENERS “MULTI-MATERIAL?”

SPAX^® Multi-Material fasteners crafted with our proprietary design and patented features allow them to perform in a wide variety of applications and materials other than wood, including concrete, masonry, light gauge sheet metal (24ga.) and plastics.

YOUR PACKAGING SAYS, “NO PRE-DRILLING.” DOES THAT INCLUDE CONCRETE?

No pre-drilling is referencing application with softwoods— not concrete. Concrete applications require pre-drilling with a carbide masonry drill bit before installing the SPAX fastener. The required hole size is published on the back of our Multi-Material product packaging.

PRE-DRILL RECOMMENDATIONS FOR HARDWOODS AND CONCRETE / MASONRY

HOW DO I USE SPAX^® FASTENERS IN CONCRETE?

Always use the correct diameter fastener for the application and drill a pilot hole using the appropriate carbide masonry drill bit found on the back of Multi-Material fastener packaging. Embedment into the masonry should be 1” min. to 1-1/2” max. Also, pre-drill the hole ¼” deeper than thread engagement to prevent the fastener from bottoming out. Be sure to clear the hole of debris before installing the fastener.

Can I use construction screws in drywall?

Yes, hanging drywall is a perfect application for SPAX Multi-Material Construction screws.

Are SPAX screws self countersinking?

SPAX patented countersunk multi-head screws are designed to be self-countersinking. Washerhead screws are designed to seat flush with the underside of the head. Overdriving washerhead screws will compromise the published allowable strength loads.

Coatings

WHAT IS HCR®?

HCR® (High Corrosion Resistant) is a dual barrier coating system designed specifically for SPAX PowerLags maximizing corrosion resistance while providing lasting strength in treated lumber applications. SPAX HCR has been independently tested to withstand 1300 hours of continuous salt spray fog according to ASTM B117 testing methodology and carries ICC-ES AC257 Treated Lumber approval. SPAX HCR is approved for use in untreated wood and above ground contact pressure treated wood for exterior, freshwater, general construction applications (American Wood Protection Association UC1- UC4A).

WHAT IS HCR-X™?

HCR-X™ (Extra High Corrosion Resistance) is our latest proprietary dual barrier coating system developed by SPAX® for our Multi-Material Construction and Deck screws. SPAX HCR-X has been independently tested to withstand 1500 hours of continuous salt spray fog according to ASTM B117 testing methodology and carries ICC-ES AC257 Treated Lumber approval. SPAX HCR-X is approved for use in untreated wood and above ground contact pressure treated wood for exterior, freshwater, general construction applications (American Wood Protection Association UC1- UC4A).

Is SPAX HCR & hcr-x approved for ground contact?

Yes, HCR and HCR-X are both approved for AWPA UC4A, ground contact, general use. Please reference AWPA guidelines for further information regarding AWPA Use conditions.

What is the zinc & yellow zinc coating?

Our zinc and yellow zinc coatings are exactly that, basic zinc coatings designed specifically for interior construction applications. While basic, these coatings have also been independently tested and approved for interior dry and damp conditions (AWPA UC1-UC2).

What is white rust?

White rust appears as a white chalky substance on zinc plated surfaces when exposed to air and water in wet conditions. Over time the zinc layer will naturally sacrifice itself to protect the carbon steel fastener beneath.

What can be used near coastal salt water?

SPAX recommends the use of 304 or 316 series stainless steel within five (5) miles of coastal salt water.

What can I use with cedar and redwoods to prevent tanin staining?

Stainless steel is recommended for cedar and redwoods to prevent staining from the natural oils (tannins) in the wood.

What is galvanic corrosion?

Also called dissimilar metal corrosion refers to electrochemical corrosion when two dissimilar metals come into contact in the presence of an electrolyte. The most common electrolyte for a wood screw would be water or salt water.

Performance

WHAT ARE SPAX® SCREWS MADE OF?

SPAX® fasteners start their life with our proprietary steel formula and are heat treated using our proprietary in-house state of the art heat treat process. What this means to you is that you are using the strongest, most durable fasteners made in the world. Our in-house process guarantees unmatched consistency that you can count on.

What is case hardening?

Case hardening is the process of hardening the surface of a fastener while allowing the metal underneath to remain soft and ductile. The allows the fastener to be strong but tough and ductile at the same time.

understanding shear strength

Ultimate shear strength of a fastener is the maximum force to induce a structural shear failure.

Allowable shear strength is the allowable shear load a fastener can be safely subjected to in a constructed assembly. Allowable values are calculated by using the ultimate tested shear strength and applying a safety factor.

understanding tensile strength

Tensile strength is the fastener’s ability to resist breaking while under tension.

what does it mean to be Code compliant?

drive types

What is t-star plus?

T-star plus is the latest evolution in fastener recess design. Our proprietary design virtually eliminates all bit wobble further reducing recess strippage. Our design offers a tight secure fit allowing the bit to grip the screw freeing the users opposite hand to hold the work piece or drive the screw in those awkward positions.

Can i use standard torx bits with t-star plus?

To take advantage of our superior bit fit we recommend using our T-Star Plus bits. However, our recess design also allows the use of standard t-star and torx driver bits for added versatility.

Torx vs t-star

Torx / T-Star / Hexlobe are all various names used to describe the standard six lobe recess found in wood screws.

WHAT DOES UNIDRIVE MEAN?

Unidrive is a Phillips/Square Drive combo system. This unique drive gives users the option of using either a Phillips drive bit or a Square drive bit to install the SPAX® fastener. Our proprietary Unidrive bit is specifically designed to maximize the bit contact surface area giving the best performance and experience.

Point styles: (4cut vs. type 17 vs. sharp point)

SPAX 4Cut – The SPAX 4CUT was born from decades of experience and research in fastener design. Our patented design symbolizes the latest technology in wood fastener performance. The proprietary 4CUT tip offers unrivaled performance in reducing wood splitting while retaining maximum thread withdrawal performance.

type 17- Originally developed for plastics with its unique slash point, it was found to offer increased performance reducing splitting in wood but with the trade-off of sacrificing thread withdrawal performance.

Sharp point – the most basic style of wood screw point. most prone to wood splitting and increased driving torque resulting in torque breaks and recess strippage.

Powerlags vs conventional lags