How to Power Wash Logs

Power Wash Only The Exterior
The interior surfaces are not critical, since they see no exposure to extreme weather. To avoid damage to interior areas, power wash the logs in the yard before they are shipped to the job site. If it is not possible to clean the logs in the yard, it should be done early in the construction cycle at the job site.

Use A 1500 PSI Power Washer
Extremely high pressure is not necessary since you run the risk of tearing up the surface and leaving it with a "fuzzy" or "hairy" condition. This will not hurt the performance of the stain, but the appearance can be objectionable and can be buffed off with an Osborn Buffing Brush.

Use A Low-foaming Detergent
The detergent will assist the high pressure water in loosening and lifting all surface residues. Use hot water. Then rinse with cold water to flush any detergent from the surface. A garden hose works well for this.

Use A Fan Spray Nozzle
Apply the water at an angle so it does not spray back into your face (be sure to wear safety goggles). Hold the nozzle at a distance, just far enough away from the surface to avoid "fuzzing" up the outer layer of wood. At this distance, the water and detergent will impact the wood with tremendous force and will remove virtually all residues, as well as creating considerable micro-roughening of the surface for enhanced stain penetration.

Apply The Finishing Touches
If you will be applying PeneTreat, apply it once the logs have become slightly damp after cleaning. Caulking the checks and cracks may be done at any time after the cleaning operation is complete and the logs are dry.

Note: The most effective method for removing mill glaze and roughening the surface is cob or sand blasting. But for many, this approach is too expensive or impractical. If this is the case, power washing or sanding the logs will remove the mill glaze.