Design Wood Screw Connections to CSA O86
Design wood screw connections in Canada to CSA O86, with real fastener geometry and strength data from suppliers including Rothoblaas and MyTiCon, alongside CCMC-approved proprietary products, so you're specifying certified performance rather than an estimate. Lateral and withdrawal resistance, plus brittle failure checks, run automatically for lumber, glulam and CLT connections. Try the calculator to specify your next screwed connection with real confidence.
Start Designing for Free See Integrated Suppliers- CSA O86:2019, CSA O86:2024
About Wood Screw · CSA O86
Canadian Screw Engineering Platform
The CSA O86 Screw Calculator is a sophisticated engineering tool designed to calculate the Factored Lateral (Nr) and Withdrawal (Pr) resistance of dowel-type fasteners. This tool helps structural engineers optimize connections in Canadian Lumber, Glulam, and Mass Timber (CLT) with strict adherence to the CSA O86-19 standard.
The engineer's guide
Wood Screw · CSA O86
Key Features
- Automated Yield Analysis: Instantly solve CSA O86 Clause 12 yield equations (Modes a-g) to find the controlling Factored Lateral Resistance (Nr).
- Limit States Design (LSD): Native support for factored loads and material resistance factors (ϕ), eliminating manual ASD conversions.
- Full Factor Support: Automates Duration of Load (KD), Service Condition (KSF), and Treatment (KT) adjustments.
- Mass Timber Ready: Specialized verification for Self-Tapping Screws (STS) in Cross-Laminated Timber (CLT) per CSA O86-19 Clause 8.
- Supplier Agnostic: Design with standard ASME Lag Screws or select from a database of proprietary CCMC-approved screws.
Overview of Structural Screw Connections
Self-tapping screws are widely used in timber engineering to transfer axial and shear forces. The module evaluates screw connections using the CSA O86 Timber Engineering Design standard together with manufacturer-specific fastener data. Supported materials: Softwood, Hardwood, Glulam (GLT), Cross-Laminated Timber (CLT), Laminated Veneer Lumber (LVL), Plywood, Steel plates for timber-to-steel connections.
Interactive Connection Model
Interactive 3D visualization displaying: member geometry, screw orientation, screw placement, applied forces.
Primary and Secondary Member Definition
Member 1 (primary), Member 2 (secondary/connected). Parameters: member material type, member dimensions, relative density (G), mechanical properties. Grain orientation relative to the screw can also be defined.
Applied Forces
Fx (shear force x-direction), Fy (shear force y-direction), Fz (axial force along screw axis). Combined shear force V automatically calculated.
Supplier and Product Library
Fastener parameters: Screw type, Nominal diameter, Shank diameter, Root diameter, Threaded length, Total screw length, Head diameter, Tip length, Tensile strength, Fastener yield strength (Fyb).
Screw Type and Thread Configuration
Partially threaded screws, Fully threaded screws — thread config determines whether fastener primarily resists axial tension, shear forces, or combined loading. Supports smart screw length selection.
Supported Design Methods
- CSA O86:2019
- CSA O86:2024
Both follow limit states design approach. Analytical procedure evaluates: timber embedment strength, fastener yielding behaviour, screw withdrawal resistance, group effects and brittle failure modes.
Screw Arrangement and Spacing
Manual Arrangement: number of screws, spacing between screws, edge distances, end distances.
Minimum Distance and Spacing Rules: auto-apply per CSA O86 provisions — spacing between screws, spacing between rows, edge distances, end distances, screw position relative to member face.
Connection Capacity Checks
- Brittle Failure: Row shear resistance, Net tension resistance, Group tear-out resistance, Splitting resistance.
- Geometry Check: verifies screw spacing/edge/end distances per CSA O86.
- Shear Capacity: based on timber embedment strength and fastener behaviour.
- Axial Capacity: based on withdrawal resistance and fastener tensile strength.
Wood Screw · CSA O86
Is this calculator consistent with CCMC reports?
Does this tool support proprietary Self-Tapping Screws (STS)?
How do you handle Lead Hole (Pre-drilling) factors?
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