After 10 years in the harshest of conditions, observe the difference between  treated and untreated   shingles

DIRECTIONS Three easy steps:
1. Apply by dipping, brush, roller, or spray (either low-pressure or airless).
2. Completely saturate wood but apply only as much as will be absorbed. Do not allow to puddle.
3. Brush-out or wipe up any puddles that may have formed before drying occurs. (If excess material is allowed to dry on the surface, a "shiny" film may be created and drying time will be slow.)

NOTE:  If complete saturation is obtained, one application will give good protection. However, protection will be superior if a second application is applied After initial application, reapply when needed as indicated by a dry, slightly weathered appearance. The south side of a structure may require additional applications more often. Each successive application will last longer than the previous one.