Should high pressure be used on asphalt shingles and wood?
High pressure can be a very destructive force when used on asphalt shingles and wood. On shingles, excessive pressure removes the granules that protect the shingle from U.V. radiation. When the granules are even partly removed, the roof begins to deteriorate at an accelerated rate, depending on the amount of granules removed. Because of this, roof life can be reduced dramatically. On wood, high pressure can splinter and remove large amounts of the soft inner wood pulp, leaving the wood with a rough and scarred look. Top • Why shouldn’t I use chlorine bleach on asphalt shingles and wood? Chlorine as a cleaning compound is harmful to the environment including shrubs, grass and other plant life. Chlorine requires multi-applications as well as tarping shrubs and the use of high pressure to rinse. Chlorine breaks down the fibers in wood and also leaves behind a residue that prevents proper bonding of protectants and sealants shortening the life of the protectant.
