EN 301:2023+A1:2026

Overview

EN 301:2023+A1:2026 is the European Standard developed by CEN for the classification and specification of phenolic and aminoplastic adhesives used in the manufacture of load-bearing timber structures. The standard outlines adhesive categories, performance criteria, and suitability for use under defined climatic exposure conditions. This document specifies adhesive requirements relevant to factory or factory-like environments, ensuring that the adhesives can deliver adequate performance and durability when bonded timber is exposed to various service classes. The standard is applicable solely to the adhesive itself, not to the final timber products or on-site gluing processes, except when these are carried out under factory-like conditions.

Key Topics

• Adhesive Classification
  The standard establishes a classification system for phenolic and aminoplastic polycondensation adhesives based on their performance in different service classes:

  • Type I: Suitable for service classes 1, 2, and 3 (from indoor conditions to exterior exposure).
  • Type II: Restricted to service class 1 (indoor applications). These types are further divided as General Purpose (GP), Finger Jointing (FJ), and Gap Filling (GF) adhesives.

• Performance Requirements
  EN 301:2023+A1:2026 specifies tests and minimum performance levels for adhesives:

  • Tensile shear strength (assessed according to EN 302-1)
  • Resistance to delamination (EN 302-2)
  • Fibre damage assessment (EN 302-3)
  • Shrinkage and static load tests (EN 302-4 and EN 302-8) The requirements help ensure structural integrity and long-term performance.

• Testing and Marking
  The document details procedures for type testing adhesives in bond lines, specifying that adhesives must pass laboratory criteria before use in manufacturing. Adhesive packages must be clearly labelled with the product type, batch number, and shelf life.

Applications

• Factory Manufacturing of Structural Timber
  The standard is geared towards manufacturers producing glued structural timber (such as glulam, finger-jointed timber, and solid wood panels) intended for load-bearing use. It supports quality control in adhesive formulation and application during factory-based production.

• Quality Assurance for Adhesive Producers
  Adhesive manufacturers utilize the standard for type testing to verify that products meet European requirements for strength, durability, and moisture resistance. The requirements also inform adhesive documentation and technical datasheets.

• Compliance in Building Design
  Product and structural engineers refer to EN 301 when specifying adhesives for timber elements exposed to defined interior or exterior conditions, ensuring structures adhere to relevant product standards (e.g., Eurocode 5).

Related Standards

• EN 302 Series
  A set of standards referenced for detailed adhesive test methods:

  • EN 302-1: Tensile shear strength measurement
  • EN 302-2: Delamination resistance
  • EN 302-3: Evaluation of fibre damage
  • EN 302-4: Effects of wood shrinkage
  • EN 302-8: Static load testing

• EN 1995-1-1 (Eurocode 5)
  Design rules for timber structures, referencing adhesive performance for ensuring safe, durable construction.

• EN 923, EN 1245, EN 12092
  These standards provide essential terminology and methodologies for measuring physical properties such as pH and viscosity, which are key for proper adhesive selection and application.

Conclusion

EN 301:2023+A1:2026 is a critical reference for adhesive manufacturers and timber structure producers operating in European markets. It provides clear, testable requirements and classification for phenolic and aminoplastic adhesives, supporting the creation of safe, resilient, and code-compliant load-bearing timber products under varied service conditions. This standard also facilitates product consistency and confidence for specifiers and end-users in the construction sector.