Lagging & Shoring

Conrad Forest Products

Douglas fir and ACZA is a match made for heavy duty applications.

The strength and resilience of Douglas fir, combined with the long-term protection of Ammoniacal Copper Zinc Arsenate (ACZA) preservative, yield a construction material that has been providing reliable service for decades — in utility poles, building poles, foundation piling, bridge girders, roller coasters, marine piling, and other demanding applications.

These attributes, plus advantageous environmental and handling features, make ACZA-treated Douglas fir ideal for lagging, whether temporary or permanent, to prevent collapse of earthwork. It is also an economical choice; Douglas fir is a readily available species grown on managed timberlands in western states.

Conrad Forest Products, with three wood treating plants and expertise in the preservation of Douglas fir, produces timbers, lumber, and poles under the "Chemonite" brand, a registered trademark of Arch Wood Protection, Inc., for ACZA-treated wood.

Available from Conrad are 3x12 and 4x12 Douglas fir timbers, rough and surfaced four sides. Other sizes can be supplied on a special-order basis. This wood is treated to the standards of the American Wood Protection Association and meets applicable requirements of model building codes.

Recent Alternative, Dependable History

Development of the original copper arsenate solution began in the 1920s. The current formulation, ACZA, was accepted in the standards of the American Wood Protection Association in 1984. A quarter-century of successful use attests to the effectiveness of ACZA-treated wood.


Chemonite® wood shares the many environmental attributes of wood itself — most notably: renewable resource, low-energy production, and carbon sequestration. The preservative process adds to these benefits by extending service life, thereby reducing demands on forests and reducing the need for shipping of replacement material.

The treatment process does not reduce the strength of the wood, although an incising factor may be needed to allow for penetration improvement.

Years of use have revealed no failures due to corroded hardware. However, the preservative contains elements which could affect inadequately protected metal. Use hot-dipped galvanized or stainless steel hardware in contact with this wood.

Use & Handling
Handling Chemonite® wood does not necessitate unusual safety measures beyond those recommended for most other construction materials. These include: Wear gloves when handling, wear safety glasses and dust mask when drilling or sawing, and do not burn treated wood.

State and local requirements vary, but, in general, lined landfills accept retired Chemonite® wood and scraps in accordance with the same requirements that apply to other building materials. They can also be used as a fuel in approved co-generation facilities. Where questions exist, confirmation from the appropriate local authority is recommended.

Chemonite® ACZA-treated wood is resistant to damage from termites and fungal decay. When used in an application for which it is intended, Chemonite wood can be expected to last for decades.

Conrad Forest Products is a multi-state operation founded in 1958 and providing a variety of treatments for far-ranging applications. Its ACZA comes from Arch Wood Protection, Inc., world’s largest supplier of wood preservatives.

For prices and other order details, contact us.

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