Ironwood® Classic Sleepers

Ironwood Classic Sleepers offer you the natural beauty and warmth of real timber, a perfect solution for modern, cost effective landscaping projects.

The technically advanced incised timber technology used for Ironwood Classic Sleepers improves treatment penetration, ensuring a longer life as well as superior protection against fungal decay and termite attack.

As a renewable resource produced in Australia from sustainably grown Australian plantation pine, Ironwood Classic Sleepers are a positive environmental choice in harmony with our natural landscape.


Ironwood Sleepers

Features & Benefits

  • Ideal for garden beds and low retaining walls.
  • Low maintenance no need to paint or stain on installation.
  • Suitable for above ground and in-ground use.
  • Kiln dried
  • H4 treated incised timber technology assists the penetration and retention of preservative chemicals into the timber, ensuring longer life and protection against fungal decay and termite attack resulting in a better treated sleeper
  • Produced in Australia from sustainably grown Australian plantation pine.

This product comes with a guarantee from Koppers Performance Chemicals. Conditions apply. See for details.


Industry Information

Finishing Timber Externally

This technical guide from Wood Solutions provides an overview of designing and detailing timber elements for maximum life, containing information to help specifiers, builders and trade professionals understand the special considerations required when selecting timber to be used in external applications.

Building with timber in bushfire prone areas

This guide from Wood Solutions provides information to help architects, designers, builders and owners understand the Construction of Building in Bushfire Prone Areas Standard AS 3959 and in particular the construction requirements for using traditional timber building methods for each Bushfire Attack Level (BAL).

Resealing – PROTIM Solignum Timber Care

This technical data sheet provides information on Koppers Performance Chemicals Protim Solignum Timber Care products and other important topics.

Timber Garden Retaining Walls Up to 1.0 m High

This design and construction technical guide from Wood Solutions contains recommendations for the construction of timber garden walls up to 1 metre high

Technical Notes

Intended Use

Ironwood Sleepers are typically used in external landscape applications such as low retaining walls and garden edging or borders.

The Ironwood Sleeper range is not structurally graded and when used in applications that require local authority building approval or engineer certification, we recommend that users consult an independent engineer or landscape architect.

Local building authorities generally do not require building approval or engineer certification for retaining walls up to a height of one metre; however, walls greater than one metre as well as those of any height which are within 1.5 metres of a building or dwelling will, in the majority of cases, require building approval and/or certification from an engineer in any case you should check your local council laws.

  • Sleepers must be supported at both ends and at 1200mm (max) intervals along the length of the board and posts should be placed in front of sleepers for increased support.
  • Sleepers should only be installed on the narrow edge (i.e. 50mm or 75mm side). They are not recommended for use in horizontal applications where sleepers are positioned on the wide edge (i.e. 200mm side) i.e. capping, stair treads or boardwalks.
  • Sleepers should be tightly constrained when used in conjunction with H section galvanised steel posts. They should be constrained in the steel channel and it is also recommended to chock either treated timber or plastic wedges between the sleepers and the steel channel on the backside of the wall for a more finished look. This should ensure that sleepers are tightly aligned to the front of the steel channel and reduce potential twisting, as well as limiting movement once installation is complete.
  • Post holes should have a 100mm layer of coarse gravel to assist with drainage.
  • A drainage pipe should be installed at the base of retaining or garden walls and extend to a free draining outlet (not a storm water drain).
  • Geotextile fabric may be used on the inside face of the wall to prevent backfill soil from flowing through spaces in wall and to assist with drainage. The use of plastic sheeting for a retaining wall is not recommended as it can lead to water build up, resulting in wall collapse. 
  • Ironwood Sienna Sleepers are preferred for use in vegetable gardens due to its non-arsenic treatment. If CCA treated sleepers are used in a vegetable garden bed a plastic film barrier to separate the soil coming into contact with the surface of sleepers is highly recommended.
  • Adequate drainage is recommended for environments that contain high levels of ground water in order to prolong the service life of sleepers. 

Construction Recommendations (for walls under one metre)

Ironwood Classic Sleepers are a wet after-treatment product, meaning they generally have higher moisture content at time of installation than seasoned timber products. As a result, they may be subject to greater levels of movement and distortion if not properly constrained during construction.

For required member size and post embedment depths, please refer to the Timber Garden Retaining Wall Technical Guide.

Treatment & Durability

Ironwood Classic Sleepers are treated with Copper Chrome Arsenate (CCA) and are suitable for in-ground use. In environments that contain high levels of ground water, installation of adequate drainage is recommended to prolong the service life of sleepers. 

The treatment used for Ironwood Sleepers protect against fungal decay and insect attack but not from weathering. Ironwood Sleepers cannot be submerged in fresh or salt water applications as a higher level of treatment is required. 

This product comes with a guarantee from Koppers Performance Chemicals. Conditions apply. See for details.

Suitable for use in all regions of Australia.


  • CCA treated timber has some limitations to its use within the Australian market.
  • CCA treated timber cannot be used for garden furniture, picnic tables, exterior seating, children’s play equipment, patio and domestic decking and hand rails.

Environmental Certification

Produced in Australia from sustainably grown Australian plantation pine.
Program for Endorsement of Forest Certification (PEFC) certificate is available upon request.


Ironwood Classic Sleepers are coloured green for ease of identification and is branded with its treatment preservative,  hazard level and treatment plant by way of an end tag or pack label.

Reseal Requirements

In any application where Ironwood Sleepers have been cut, notched, rebated or drilled the exposed area should be resealed with an appropriate reseal product. Such as PROTIM® SOLIGNUM® CN TIMBER OIL. This is a copper-based solvent/oil formulation that is green in colour. This will ensure the treatment envelope remains intact and provides the best long term protection.

If a paint system is to be applied after resealing, allow time for the CN oil to be absorbed into the timber and then follow paint manufacturers recommendations. 

For more information about PROTIM® Solignum® Timber Care please refer to the Technical Data Sheet available from Koppers Performance Chemicals.

Fixings & Fasteners

For normal applications all fasteners and fixings that will be in contact with preservative treated pine should be hot dipped galvanised. In harsh environments such as those close to the salt water, stainless steel or similar fixings should be used.


When handling and working with Ironwood Classic Sleepers, users are recommended to wear gloves, dust masks, ear protection and safety glasses at all times. Please refer to above Material Safety Data Sheet (MSDS) for full details.

Waste Disposal

Off-cuts can be disposed of as normal landfill waste. Do not burn treated timbers. Please refer to above Material Safety Data Sheet (MSDS) for full details.


Ironwood Sleepers

Ironwood Sleepers

Classic Sleepers