Pressure washing and surface lifespan

Roofs. This is the clearest case of cleaning method affecting lifespan. Granules protect the asphalt beneath them from UV. Remove them and the shingle ages faster. ARMA's warning is that pressure washing will cause granule loss and very likely premature failure; Malarkey adds that excessive walking on shingles does the same. Both point at the same conclusion: clean roofs rarely, gently, and preferably not by walking around on them.

Wood. Today's Homeowner describes splintering, etching and stripped wood fibers from excessive pressure and puts anything above 2,000 PSI in that category for wood. Fixr's deck guidance warns that too much pressure leaves grooves and can chip, peel and crack boards. Furred, grooved wood absorbs more water and holds finish worse, which shortens its life independent of the visible damage.

Masonry. NPS notes that erosion of mortar joints permits increased water penetration, which then requires repointing, and that too-high pressure can etch some brick and soft stone. A rougher surface also holds dirt better and makes future cleaning harder - the damage compounds.

Driveways and hardscape. Here regular cleaning generally helps. Fixr recommends washing a driveway at least once a year to prevent buildup damage and before each resealing. On paver surfaces, be aware that high pressure blasts out joint sand, so plan to re-sand.

How long does a clean last? That depends on sun, shade and moisture more than on the product used. A shaded north elevation under trees can regrow visible algae within a year; a sunny, open wall can go considerably longer. Anyone guaranteeing a specific number of years of cleanliness is guessing about your microclimate.