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How do I apply Penetreat Log Preservative?

  1. Mix PeneTreat at a rate of 1-pound (1 loosely packed quart) to 1-gallon of water.
  2. Wood must be clean and bare; free of dirt, wax and surface finishes and above 40°F and rising (wood surface temperature).
  3. Apply PeneTreat at the rate of 1 mixed gallon per 150 ft2 of wood surface. Apply a second coat 4 to 24 hours later. Thoroughly soak cut ends.
  4. Coat the logs with a water-repellent finish after the PeneTreat solution has thoroughly dried. Use a moisture meter to verify that the log’s moisture content doesn’t exceed 19%.
  5. Read the Section “Application Methods” for other types of application.

Where to use PeneTreat

Use PeneTreat on above-ground wood surfaces, including logs, timbers, dimensional lumber, siding, etc. Wood subject to direct moisture contact must be coated with a good water-repellent finish after treating with PeneTreat. If using Log Keeper™, be sure to apply PeneTreat first.

Surface Preparation

Wood must be bare; free of dirt, wax and surface finishes. Remove all previous coatings by cob blasting, sanding, chemical stripping, sandblasting and/or high-pressure water. Surface discoloration from mold or mildew should be treated with CPR Log Cleaner & Brightener before applying PeneTreat.

Do not apply to frozen wood. Log (not air) temperature must be between 40°F and 90°F. It is best to apply PeneTreat to dry wood.

Mixing PeneTreat

Mix at the rate of one pound, or loosely packed quart, to one gallon of water. The PeneTreat mixture requires only mild stirring before application. The mixture will be clear and water thin.

With this mixture, all application methods described below will yield a minimum retention level of 0.24 pounds per cubic foot boric acid equivalent to 1/2”.

Methods of Application

PeneTreat may be applied by:

  • brushing
  • spraying
  • dipping
  • kerf flooding
  • hole flooding.

    Full immersion dipping yields the deepest and most complete protection, especially with large logs.

    Kerf-flooding accompanied with brushing or spraying, yields nearly the same level of protection as dipping.

    Brushing and spraying can completely penetrate dimensional lumber and can provide excellent “shell” protection for timbers and logs to a depth of 1/8”-1/2” — which is adequate for most applications.

    NOTE: Diffusion of PeneTreat into the wood begins immediately and requires several days for completion.

    With “shell” protection in large logs or timber, all pre-existing insect larva may not be killed. Upon maturing they may emerge from the wood. Insects must ingest the substance to be killed—PeneTreat is not a contact killer. Further insect infestations, however will be prevented.

    Brushing or Spraying Penetreat

  • Apply PeneTreat at a rate of 1 mixed gallon per 150 ft2 of wood surface.
  • Apply a second coat 4-24 hours later.
  • Thoroughly soak cut ends and apply to checks and cracks.

    Kerf-flooding and Spraying/Brushing

  • Logs 9” in diameter and larger are often kerfed to control unwanted checking.
  • When kerfing a log in the shape of a trough (with 3/8” wide chain saw to a depth of 3”), just pour the PeneTreat solution into the kerf.
  • Fill the kerf at a rate of 15-20 lineal feet per mixed gallon.
  • Let soak. It will take 1-2 days for the logs to absorb all the liquid. Protection may also be gained by pouring powdered PeneTreat into the kerf (0.2 to 0.3 pounds per lineal foot).
  • Pour water into the kerf to dissolve and carry the PeneTreat into the wood.
  • Brush or spray the exterior of the logs after either of these methods as described above.
  • Hole-flooding is similar to kerf-flooding.

    NOTE: Be sure the kerf or holes do not affect the structural strength of the log.


  • Dip logs or lumber in PeneTreat for 6-10 minutes, depending on log diameter.
  • Let excess liquid drain back into the tank, dip again 24 hours later.
  • Cover wood with a tarp or place in a shed for at least 48 hours prior to coating with a good exterior finish.
  • Use of an anti-sap stain biocide is recommended in conjunction with PeneTreat.

    HINT: Runoff from vertical walls may be contained by using plastic sheeting to form an accumulation basin. The trapped liquid may then be recycled and will be prevented from injuring nearby foliage.

    After Applying PeneTreat Borate Wood Preservative

  • Treated wood must be protected from direct contact with moisture or the active ingredient may leach out.
  • It’s best to wait at least 48 hours (in warm weather, longer in cool weather) after applying PeneTreat to coat wood with a water-repellent finish.
  • Let the surface thoroughly dry and brush away any crystals that appear before staining. Use a moisture meter to verify that the logs’ moisture content doesn’t exceed 19%.

    Clean Up Use soap and water to clean equipment, skin and clothing

    Storage and Disposal Do not contaminate water, food or feed by storage or disposal.


    Store in a dry place. Do not store where children or animals may gain access. Store above 20°F.

    PeneTreat Disposal

    Wastes resulting from this product may be disposed on site or at an approved disposal facility. Check your state and local regulations. For more detailed information refer to section 13, 14 & 15 of the PeneTreat MSDS.


    Because of many varying conditions affecting use and application, manufacturer warns buyer that these conditions may impair or vary results or effects of the use of this product. Therefore, complete prevention of decay or insect infestation is not guaranteed. Neither the manufacturer nor seller shall be liable in respect to any injury or damage suffered by reason of use of this product for a purpose not indicated on the label or when used contrary to the directions or instruction herein nor with respect to breach of any warranty not expressly specified herein.

    Precautionary Statements Hazards to Humans and Domestic Animals

    CAUTION: Harmful if swallowed. Avoid contact with eyes. Wash thoroughly after handling. Avoid contamination of food and feed. Do not leave container where children or animals may gain access. Use a dust mask when handling the dry powder.

    Statement of Practical Treatment

  • If swallowed, immediately contact a physician or Poison Control Center.
  • If these are unavailable, give the person 1 or 2 glasses of water and induce vomiting by touching the back of the throat with finger.
  • Do not induce vomiting or give anything by mouth to an unconscious person.
  • If in eyes, flush with plenty of water. Get medical attention if irritation persists.
  • If on skin, remove affected clothing and wash skin with soap and water. Wash clothing before reuse.
  • If inhaled, move person to fresh air. Apply artificial respiration if indicated. Contact a physician if warranted.

    Environmental Hazards

    PeneTreat or PeneTreat solutions carelessly spilled or applied to crop land or growing plants, including trees and shrubs, may kill or seriously retard plant growth. Do not contaminate water when disposing of equipment wash-waters. Do not apply directly to bodies of water.