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Prolam H5 Structural Glulam Posts

Prolam H5 Posts are structurally engineered timber elements, with high strength, dimensional stability and premium visual appearance. Available in sizes 88x88mm to 300x300mm in PL8 and PL12 strengths.

Ideal for gate posts, fence posts, supporting trellis, pergolas, fences, decks, and carports.

  • Available in four finishes: Sanded, Pre-Primed, Sanded & Sealed, Bandsawn
  • Sizes: 88x88, 112x112, 135x135, 180x180, 220x220, 260x260, 300x300mm
Key Features
  • H5 Posts Codemark Certified 
  • Do not need post brackets 
  • Gives bracing units (Tables 11 & 12) 
  • Structurally stable 
  • Available in PL8 and PL12 strengths
  • Superior fire resistance 
  • Good load carrying capacity 
  • Won't twist or warp
  • Easy to specify on the Prolam Specifier
Structural Timber
Scope of Use

Ideal for gate posts, fence posts, supporting trellis, pergolas, fences, decks, and carports.

  • Available in sizes 88mmx88mm to 300mmx300mm
  • PL8 and PL12 strengths
  • Available in four finishes: Sanded, Pre-Primed, Sanded & Sealed, Bandsawn
Limitations on Use
  • This laminated treated product must be protected from the elements until it is sealed, Prolam's structural timber can be supplied with a temporary sealer if required.
    • Timber naturally absorbs moisture from the surrounding environment. This can cause the product to alter dimensionally. 
    • All exposed structural timber must be sealed with a good quality paint or stain system within 14 days of delivery to dramatically reduce the incidence of dimensional change and increases longevity.
    • All cuts, holes and rebates must also be sealed to prevent the ingress of moisture.
  • Prolam structural timber products can be used in specific fire performance situations, and must be designed in conjunction with a fire engineer
  • Must be designed and installed in accordance with the Prolam H5 Post Design & Install Guide
  • Use in accordance with the Prolam Warranty & Maintenance information and Prolam Timber Coating Requirements document


Statement of Building Code Compliance

Prolam structural laminated timber installed in accordance with the Prolam installation requiements, will comply with the below performance clauses of the New Zealand building code:

  • Structure B1/AS1: meets the requirements of B1.3.1 B1.3.2 B1.3.3 (a, b, f, j, m, q) B1.3.4 (a, b, c, d, e); AS1170:2002 for engineering span tables, AS/NZS 1328:1998 and AS5068 for building element
  • Durability B2/AS1: meets the requirements of B2.3.1(a) B2.3.2. All timber is treated in accordance with NZS3640. Prolam treats it’s own timber, and is third party audited to ensure compliance to the New Zealand treatment standard.
  • Protection from Fire C: APA Evaluation of Char Rate (ASTM E119), TT- 118, January 2015; meets the requirements of C6.3 C6.4. Where members are required to have a fire resistance rating the designer can use the follow standards for FRR design: TT-118 OR: NZS 3603:1993 (section 9).
  • Hazardous Building Materials F2/AS1: meets the requirements of F2.3.1. Timber treatment suppliers meet NZS3640, which includes flash-off requirements.
In-Service History

This product was born with the company in 2002. Has been on the market for 20 years.

Other Performance Attributes

Warranty and Maintenance:

  • Prolam posts treated to H5 may be used in exterior situations provided that they are finished with a paint or stain coating.
  • Maintaining Prolam beams requires that painted timber is be recoated every 24 months and stained timber is recoated every 12 months. Particular attention must be paid to ensuring that exposed cut ends are re-stained or re-painted.
  • Where a cut end is sealed with a proprietary capping, it is important to ensure that the capping is tightly sealed.
  • Prolam beams should always be painted with light colours or dark colours with light reflectance value (LRV) of greater than 45%. Colours with an LRV of 45% or less are not recommended, as they can absorb heat which may result in timber distortion and cracking.
  • Please see Coating Requirements document for more details
Prolam H5 Posts Design & Install Guide


Structural Timber Guide 2023
Prolam Span Tables
Specify: Prolam Specifier Online


Prolam Post Fixings


Prolam Timber Coating Requirements


Prolam Warranty & Maintenance


Prolam Product List 2023

For 20 years, Prolam has been a proud manufacturer of New Zealand structural laminated posts and beams.

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