GLTAA Product Certification System
The current Australian Standard for the manufacture of glulam, AS1328-1987, was outdated as a modern standard, because it is a prescriptive guide to manufacturing rather than being performance based. There is no system within the standard by which to clearly assign mechanical properties to glulam. Hence, in Australia, glulam which has been manufactured in accordance with AS1328-1987 has been marketed without performance substantiation. The GLTAA product certification process has addressed this inadequacy by establishing a performance guide, a third party accreditation process and ongoing auditing.

The GLTAA product certification process consists of the following major elements:

  • Adoption of a quality assurance system based on AS3902 with adaptation to individual plant process capabilities.
  • Establishment of plant process capabilities through a qualification testing process. The process capabilities are dependent on lamination end joint configuration, base raw material, etc. This establishes the mechanical properties of the glulam manufactured in plant conditions.
  • The continued performance of glulam is verified by in-plant process controls on a daily basis.
  • Further performance verification is gained through regular audits by the external auditors appointed by the GLTAA.
  • Accredited manufacturing plants are issued with a certificate upon qualification and accreditation and are subsequently permitted to use the GLTAA mark. The certification can be withdrawn at the discretion of the GLTAA, should ongoing audits establish non-conformance within the quality assurance system.
  • The quality assurance system is regarded as one of the best in the industry. With proper management, ongoing improvements are achieved in controlling quality and therefore cost of production.

GLTAA Inspectorate
The GLTAA’s inspectorate for its quality assurance system is Monash University, through the Monash Timber Engineering Centre (MTEC). The MTEC was instrumental in establishing the GLTAA, calling the inaugural meeting of industry members at which the association first formed.

MTEC staff, who act as the inspectorate, are also prominent in the timber industry as quality assurance consultants, in the publication of timber engineering literature, in pure and applied research in timber and in preparation of national and international standards relating to timber.; MTEC’s Professor Bob Milner is Chairman of the code committee TM/4 which prepared the Glued Laminated Structural Timber code, AS1328. This code has been redrafted to incorporate provisions whereby process capability studies and the associated quality assurance systems become a mandatory part of glulam production.

MTEC is directly involved in all qualification inspections, which form part of the qualification process, in conjunction with a local inspector. Subsequently, the local inspector performs the three inspections per annum. The inspections are reported to the inspectorate.

GLTAA Certificate of Conformance
Upon receiving plant accreditation, the member is issued a “Certificate of Conformance” which makes the following statement:

The Glued Laminated Timber Association of Australia (GLTAA)

hereby certifies that

plant is licensed by the Glued Laminated Timber Association of Australia to use the GLTAA Mark in respect of products listed in the Schedule A which comply with applicable provisions of GLTAA Industry Standard, GLTAA 4-91, Glued Laminated Structural Timber, that the quality control system in effect at said plant is periodically inspected and verified by the Glued Laminated Timber Association of Australia Inspectorate and that, in the judgement of GLTAA, said company is capable of complying with applicable manufacturing and testing provisions of said Standard in respect of products manufactured at said plant and listed in Schedule A. Conformance with the Standard in respect of any specific or particular product is the sole responsibility of the manufacturer; GLTAA’s guarantee here-under being that the said company is qualified to produce product meeting the said Standard that its plant is periodically inspected and verified by the GLTAA Inspectorate.

The GLTAA product certification and Quality Assurance Program is detailed in the following documents:

  • AS1328 – 1991 Draft Australian Product Standard
  • GLTAA 4/91 Industry Product Standard
  • GLTAA 1/91 Inspection Manual
  • GLTAA 3/91 Inspection Procedures

All Glulam products which are quality assured by processes detailed in these documents will be branded, stamped or marked with the GLTAA Quality Mark.

NB: Glulam product produced by GLTAA members which is not quality assured by the GLTAA will be identified in exactly the same manner, but use of the Quality Mark is not permitted.

  1. GLTAA Quality Mark
  2. Producers Accreditation Number
  3. Proprietary Brand Name (if applicable)
  4. Service Class:
    1. EMC not exceeding 12% in service
    2. EMC not exceeding 20% in service
    3. EMC over 20% in service
  5. Appearance Grades:
    A. Clear finish exposed Glulam
    B. Paint grade Glulam
    C. Structural Glulam only, appearance not important
  6. Mechanical Properties Grade:



  1. Symbol for Precambered or Straight Glulam:
    C = Precambered to 600M radius
    S = Straight