The MTC Solutions Structural Screw Catalog is the most comprehensive guide to ASSY® self-tapping screws (STSs). Within its pages, designers and installers will discover a wealth of practical and technical information, arranged in an easily navigable chapter format. This guide includes crucial design formulas for determining connection capacities and offers specific installation guidelines, accounting for various geometry requirements across a wide variety of scenarios. Additionally, this catalog provides tool recommendations, defines service conditions, and outlines all fastener references for incorporation into your design specifications. This makes it ideal for any project involving engineered wood products such as cross-laminated timber (CLT) and glue-laminated timber (glulam).
The Structural Screw Catalog serves as an indispensable tool for designing connections and ensuring proper installation of fasteners in your cutting-edge, code-compliant mass timber projects.
Updated Geometry Requirements for Fully Threaded Self-Tapping Screws in Glulam and Timber (Table 3.5)
Values updated to match with the CCMC
Notes about species prone to splitting removed as the CCMC already accounts for this with larger spacing in DFir
General updates & fixes:
Various organizational updates in the General Notes to the Designer
Various organizational updates in the General Notes to the Installer
Various table nomenclature updated in the Accessories section for a better reference
Minor footnotes updates
Patch Notes
February 13, 2025
Consolidated all MTC fastening solutions and related accessories in one guide, including the NEW 12 mm-diameter ASSY 4.0 fasteners.
Updated General Notes to the Designer
Reflect most recent test data and core hardness/hydrogen embrittlement (HE) best practices
Include fastener durability considerations
Updated General Notes to the Installer
Better clarity on pilot hole and predrilling recommendations, service conditions, and durability
Updated Fastener Durability section, including MTC’s HE quality control program.
Updated Appendix (D), Service Conditions and Durable Design Guidance, with NEW layout and content, including:
Service conditions and other factors impacting corrosion
Increased corrosion risk categories
Hydrogen embrittlement
Suggested fastener specification language
Detailing considerations for wet service conditions, sheltered connections, moisture-related movement, steel side plates, green wood, and end grain connections
General updates & fixes:
Updated Connection Classification and Formulas sections
Updated guide layout for enhanced document navigation
Light improvements to text and graphics
Updated multiple footnotes to clearly specify all relevant derivation methods
Updated geometry requirements for fasteners installed in glulam and CLT based on our latest ICC-ES reports
Updated all design values in accordance with the latest test values and ICC-ES reports
Patch Notes
November 15, 2024
NEWLY UPDATED requirements for MTC structural fasteners in compliance with the CSA O86:24.
NEW Section 12.12 for self-tapping screws.
NEW requirements for fastener hardness!
NEW layout for an enhanced user experience.
Consolidated all MTC fastening solutions and related accessories in one guide, including the NEW 12 mm diameter ASSY 4.0 fasteners.
NEW General Notes section split into two categories:
Notes to the Designer
Notes to the Installer
NEW sections for connection classification and resistances for single and multiple fasteners, including details for
fasteners loaded in tension
fasteners loaded in shear
lateral connections with axially loaded inclined fasteners
NEW Fastener Durability section.
NEW screw selection flow chart to quickly find the right fastener for the application at hand.
All Specified Resistance Values updated in accordance with ICC-ES AC233 certifications.
NEWLY UPDATED Geometry Requirements for fasteners in glulam and CLT face applications in compliance with CSA O86:24.
NEW product section: Self-Drilling Dowels, featuring our cylinder-head dowel fasteners designed for internal knife plate connections.
NEW in-depth Appendix section including:
(A) General Connection Information
(B) Additional Geometry Considerations
(C) Steel-to-Wood Connection Detailing
(D) Service Conditions and Durable Design
(E) Step-by-Step Installation Guidelines and Recommendations
General updates & fixes:
Guide text and graphics overall.
Updated Geometry Requirements for fasteners in CLT edge applications in compliance with ETA-11/0190.
2.2: Updated bending yield values in accordance with ESR.
Patch Notes
February 5, 2024
NEW screw selection flow chart.
NEW Appendix section (F): Service Conditions and Durable Design.
Lateral Connections with Axially Loaded Inclined Fasteners update: removed 0.9 factor from Z’r calculation (page 17).
Fully Threaded Fastener Series general update: head diameter, design values and geometry requirements following latest update to ICC-ESR-3178 (2023).
General updates & fixes:
Updated references from NDS 2018 to NDS2024.
Updated Rα – Angle to Grain Reduction Factor (page 18).
Updated Service Conditions and Corrosion section (pages 22-23).
Updated Appendix (A): Installation Guidelines.
Updated Appendix (D): Geometry Requirements for inclined screws.
Updated Appendix (E): Steel Plate Detailing to reflect requirements in ICC-ESR-3178 (2023).
Improved text consistency.
Patch Notes
October 17, 2023
NEW accessory tool: the multipurpose MTC Pre-Drilling Jig (replacing previous versions of the product).
NEW LRFD buckling resistance values (Wc) for fully threaded fasteners.
General updates & fixes:
Updated allowable insertion torque values for all fastener series.
Updated predrilling and pilot hole recommendations.
Updated table nomenclature.
Fixed various graphical issues.
Patch Notes
March 28, 2023
Consolidated all MTC fastening solutions and related accessories in one guide.
NEW General Notes section split into two categories:
Notes to the Designer
Notes to the Installer
NEW sections for connection classification and resistances for single and multiple fasteners.
Updated the Design Formula Summary section, now complete with:
NEW product section: Self-Drilling Dowels, featuring our cylinder head dowel fasteners designed for internal knife plate connections.
NEW in-depth appendix section including:
Step-by-step installation guidelines
Lateral connection knowledge
Geometry requirements
Steel-to-wood connection details
Patch Notes
April 17, 2018
Introducing the Structural Screw Catalog for United States-based projects, featuring ASSY 3.0 partially and fully threaded STSs with detailed measurements for each of their parts.
The Lateral Connection Design section outlines strength resistances for specific woods and their connections, including distinctions for plywood and engineered wood products based on their respective material grades.
The Spacing and Edge Distance Requirements section features a table on timber connection geometry without predrilling.
The CLT Requirements for Non-Predrilled Self-Tapping Fasteners includes a table on CLT connection geometry without predrilling and details on group action for staggered fasteners.
Includes a Predrilling Recommendations table and ASSY Pilot Hole Length Recommendations
The ASSY Reference Design Values section features tables on Withdrawal Design Values (W), Head Pull-Through Design Values (P), Allowable Fastener Tensile Strength Values, and Reference Lateral Design Values (Z).
Patch Notes
April 15, 2018
Introducing the Structural Screw Catalog for Canada-based projects, featuring ASSY 3.0 partially and fully threaded STSs with detailed measurements for each of their parts.
The Lateral Connection Design section outlines strength resistances for specific woods and their connections, including distinctions for plywood and engineered wood products based on their respective material grades.
The Spacing and Edge Distance Requirements section features a table on timber connection geometry without predrilling.
The CLT Requirements for Non-Predrilled Self-Tapping Fasteners includes a table on CLT connection geometry without predrilling and details on group action for staggered fasteners.
Includes a Predrilling Recommendations table and ASSY Pilot Hole Length Recommendations
The ASSY Reference Design Values section features tables on Withdrawal Design Values (W), Head Pull-Through Design Values (P), Allowable Fastener Tensile Strength Values, and Reference Lateral Design Values (Z).
All Fasteners, One Guide
All MTC Solutions structural fastener references are consolidated in one document for a convenient design and ordering process.
Fastener Connection Design Made Easy
Near the beginning of the document, you will find sections dedicated to detailing connection resistances for both single and multiple fasteners in various loading conditions. There is also a formula summary section, complete with the references you need to efficiently design connections with structural screws. It features formulas for Adjusted Withdrawal, Buckling, and Head Pull-Through design values, as well as Fastener Tensile and Shear strengths, and more!
For Both Designers and Installers
The Structural Screw Catalog is prepared with both designers and installers in mind. General Notes are divided into separate sections for designers and installers to ensure ease of use. Designers will find helpful references like design values and geometry requirements for our fasteners, while installers can especially benefit from the appendix, which includes step-by-step installation guidelines and recommendations for predrilling, pilot holes, and installing steel-to-wood connections.
A 2-in-1 Package
The Structural Screw Catalog pairs especially well with our Structural Screw Connection Design Guide, creating the perfect reference tool for designing mass timber connections with our fasteners. The Structural Screw Catalog is a do-it-yourself guide that gives you the flexibility to design any connection you may need. The Structural Screw Connection Design Guide, on the other hand, offers pre-engineered, cost-efficient solutions for a wide variety of mass timber and light-frame connections commonly found in the industry.
