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Wood Treatment


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Wood Treatment Contents:

CSI NUMBERS
DEFINITION
CONSIDERATIONS
COMMERCIAL STATUS
IMPLEMENTATION ISSUES
GUIDELINES

RESOURCES

CSI Numbers:


DEFINITION:

Wood treatment refers to protecting wood from damage caused by insects, moisture, and decay fungi.


CONSIDERATIONS:

Three primary methods of wood treatment currently prevail: creosote pressure-treated wood, pentachlorophenol pressure-treated wood, and inorganic arsenical pressure-treated wood. The pressure-treating process is done by commercial facilities and made available to users in the final wood product. Copper napthenate, zinc napthenate, and tributyltin oxide are other wood treatment options that can be site applied. All of these treatment processes involve dangerous chemicals .

Chromated copper arsenate (CCA) is the most popular wood treatment product available today. The chemicals are inert within the material and offer protection from moisture and decay fungi. The chemicals do not penetrate into the heartwood effectively so a sealer is advisable on cut ends of CCA treated wood. Although CCA treated wood is sawn on jobsites, hardly anyone seals the cuts. All pressure treated products require adherence to safety precautions approved by the EPA. The safety precautions are listed in the Guidelines section.

EPA regulations govern the manufacture of pressure-treated materials and require extensive environmental safety precautions. Wood treatment does offer a method to extend the usable life of our wood resources.

The toxicity of the chemicals used in wood treatment has led to research into less toxic methods such as the use of borates derived from the natural element boron (borax). Borates (from boron) are used in wood in New Zealand and Australia and offer insect protection and fire retarding benefits to wood. Full-scale commercial introduction of borates in the U.S. awaits resolution of the leaching problem of borates. Since borates are water soluble, water dilutes them and leaves the wood unprotected from decay after a period of time. In a location unexposed to water, they are effective in preserving wood; site applied borate products are available.

Borate pressure-treated wood is being offered by one company in the U.S. (primarily for the Caribbean market). They are promoting the concept of using borates for all the wood in a house. This eliminates the need for termite protection by any other means and prevents decay fungi.

Ammoniacal copper quatenary (ACQ) is a new wood preservative currently being introduced. This material employs preservative components that are listed in EPA's classification as "General Use" pesticides. This is a less toxic material that CCA and it performs similarly.

Commercial
Status
Implementation
Issues
technology suppliers cost financing public regulatory
Wood Treatment
Legend
green Satisfactory
yellow Satisfactory in most conditions
red Satisfactory in Limited Conditions
black Unsatisfactory or Difficult

COMMERCIAL STATUS

TECHNOLOGY:

Borate treatment is not technologically mature in comparison with CCA treated wood. Leaching problems must be resolved for borate treatment to substitute for CCA pressure-treated wood.

SUPPLIERS:

Suppliers of site-applied borate products are uncommon. Commercial application of borate treatment is just becoming available.

COST:

Site-applied borate treatments exceed the cost of other chemical treatments due to shipping costs. Borate pressure-treated material adds about $2,500 to the costs of an average sized frame house.


IMPLEMENTATION ISSUES

FINANCING:

Available if the borate treatment is code compliant.

PUBLIC ACCEPTANCE:

There is not widespead awareness of borate treatment. However, reduced health risk should be seen as a positive characteristic.

REGULATORY:

Any wood within 6 inches of the finish grade must be factory treated or have natural resistance (e. g. heartwood of cedar, redwood, or black locust). (See also
Non-toxic Termite Control)

GUIDELINES

  • 1.0 Precautions
  • It is required that this information be available to persons using Inorganic Arsenical Pressure-Treated Wood (CCA), Pentachlorophenol Pressure-Treated Wood, Creosote Pressure-Treated Wood.

  • 2.0 Borate site-applied products
  • 3.0 ACQ
  • 4.0 CCA
  • 5.0 Other Chemical Treatments
  • 6.0 Decay resistant domestic woods
  • 7.0 Borate Pressure-Treated Lumber

  • RESOURCES


    PROFESSIONAL ASSISTANCE



    COMPONENTS / MATERIALS / SYSTEMS


    Borate products

    GENERAL ASSISTANCE:


    INTERNET RESOURCES


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