What is the difference between single-shear and double-shear connections?

In a single-shear connection, the fastener crosses one shear plane between two members (e.g. a nail connecting two overlapping boards).

In a single-shear connection, the fastener crosses one shear plane between two members (e.g. a nail connecting two overlapping boards). In a double-shear connection, the fastener crosses two shear planes — typically a central timber member with steel plates on both sides, or a steel plate sandwiched between two timber members. Double-shear connections have approximately twice the capacity of single-shear for the same fastener, and they produce a more balanced, symmetric load path.

Why this matters

This question relates to Timber Connection Design: Steel Plates, Dowels & Modern Fasteners, which covers the broader topic in detail. Understanding this specific aspect helps architects, builders, and timber dealers make informed specification decisions.

For full context and additional technical detail, see our comprehensive guide:

→ Timber Connection Design: Steel Plates, Dowels & Modern Fasteners

Related questions

• What are the main types of timber connections?
• How do you design timber connections for fire resistance?
• What is the advantage of concealed connections in timber?

About this answer

This answer is part of the PuurModulair Knowledge Base — comprehensive timber specification guidance for architects, builders, and dealers across the UK, EU, and Scandinavia.