Overview
ISO 6076:2023 - "Adhesives - Installation of floor coverings, wood flooring, levelling compounds and tiles - Specification of trowel notch sizes" defines standardized trowel notch sizes, shapes, codes and tolerances used when combing adhesives, thin-bed mortars and levelling compounds. The standard establishes measurements, labelling rules and material recommendations so notched tools (trowels and strips) are consistent and comparable across manufacturers and regions.
Key topics and technical requirements
- Notch geometries: triangular (including pointed), rectangular, U-shaped and semi-circular profiles. Inner corners are rounded (radius ~0.2–0.3 mm, average 0.25 mm).
- Dimensional parameters: bridge width (a), notch width (b), notch depth (c) and notch angle (γ) are specified and illustrated.
- Tolerances: a, b, (a + b) and c have tolerances of ±0.1 mm; notch angle γ tolerance is ±0.5°.
- Material and durability: recommends spring steel with a minimum hardness of 46 HRD and a sheet thickness not less than 0.5 mm to reduce wear and preserve notch geometry.
- Designation and labelling: notched trowels conforming to ISO 6076 must be labelled as Manufacturer / notch size code / Reference to this document. The standard assigns specific ISO notch size codes and includes a comprehensive Table 2 of sizes and a geometric factor for each code.
- Geometric factor: a calculated area-per-unit-length value used to sort trowels by geometry. It is a first approximation of adhesive application rate but does not replace empirical considerations (adhesive viscosity, application angle, substrate, etc.).
- Regional cross-reference: Annex A maps ISO notch codes to common European, Japanese and US notch designations for interoperability.
Applications and users
ISO 6076 is practical for:
- Trowel and tool manufacturers - design, production tolerances, and labelling of notched spatulas and strips.
- Adhesive and mortar producers - specifying recommended notch sizes for product data sheets.
- Flooring contractors and installers - selecting the correct trowel to achieve target adhesive coverage and consistent installation quality.
- Specifiers, procurement and QA teams - ensuring interchangeability, correct performance, and durable tooling.
- Test labs and standards bodies - harmonizing test methods that reference notch geometry.
Practical benefits include improved estimation of adhesive consumption, repeatable installation performance, clearer procurement specifications and reduced on-site variability.
Related information
- ISO 6076 was prepared by ISO/TC 61 (Plastics) in collaboration with CEN/TC 193 (Adhesives).
- The document contains no normative external references but provides extensive tables and illustrations (Table 2 and Annex A) for direct implementation.
Keywords: ISO 6076, trowel notch sizes, notched trowel, adhesives, floor coverings, wood flooring, levelling compounds, tile installation, notch designation, geometric factor.
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