ISO 5328:1978

Overview

ISO 5328:1978 - Solid wood paving blocks - Softwood paving blocks - Quality requirements is an ISO international standard that defines quality and acceptance criteria for softwood (resinous) solid wood paving blocks used in both covered (indoor) and open (outdoor) paving. The standard specifies which wood and sawing defects are permissible and the corresponding acceptance conditions, so that manufacturers, suppliers and specifiers can ensure consistent material quality for pavements.

Key topics and requirements

• Scope: Applies to solid softwood paving blocks for indoor and outdoor use; establishes quality specifications and defect limits.
• Defect acceptance table: The core of ISO 5328:1978 is a table listing common wood and sawing defects with explicit acceptance conditions:
  • Rot and mould: not permitted.
  • Pith (moelle): permitted.
  • Grain deviation and burls (inclination du fil et ronce): permitted when not caused by biological deterioration.
  • Discoloration: permitted.
  • Surface checks and splits: superficial checks/fissures allowed; through‑going splits are not allowed on the exposed face and are limited on other faces (generally not more than 50% of the block dimension in the relevant direction).
  • Inter‑bark (entre‑écorce): permitted as interrupted traces if not visible on the exposed face.
  • Knots: rounded/oval and partially sound knots are restricted on the exposed face; on other faces permitting up to two knots per block within size and location limits (e.g., not exceeding one‑third of width or diameter and positioned at least 20 mm below exposed edges). Through knots are excluded from exposed faces.
  • Worm holes and holes: excluded from the exposed edges; allowed on other edges subject to limits (e.g., not exceeding 20% of length/width/height).
  • Resin pockets: superficial resin pockets permitted.
  • Saw marks: allowed on all faces provided depth does not exceed 2 mm.
  • Other defects: unspecified defects are acceptable only if they do not impair strength or durability.
• Marking and supply: Blocks exceeding the permitted defects must not be marketed as “ISO solid wood paving blocks.”

Applications and users

• Who uses it: timber manufacturers, block producers, quality inspectors, procurement teams, architects, landscape contractors, heritage restorers and standards bodies.
• Practical uses:
  • Quality control during production and acceptance inspections.
  • Procurement specifications and tender documents for paving projects.
  • Design guidance when selecting softwood paving blocks for interior or exterior paving where appearance and durability matter.
  • Reference for repair, restoration and compliance checking of wood pavements.

Related standards

• ISO 5327 - Solid wood paving blocks - General characteristics (referenced in ISO 5328:1978).
• Developed by ISO/TC 99 (semi‑manufactured wood products).

Keywords: ISO 5328:1978, solid wood paving blocks, softwood paving blocks, quality requirements, wood defects, acceptance conditions, paving blocks standard, indoor/outdoor paving.