Pressure washing uses force
High-pressure water physically knocks contamination off a surface. It works on dense, non-porous, structurally sound material — concrete driveways, sidewalks, paver patios, block walls, industrial slabs. On the right surface it is fast and effective.
Soft washing uses chemistry
Soft washing applies a cleaning solution at low pressure, lets it dwell long enough to break down organic growth and bonded dirt, then rinses gently. The cleaning is done by the solution, not the water. It is the correct method for stucco, painted siding, wood, roof tile, shingle and most stone.
Why the distinction matters financially
Concrete tolerates 3,000 PSI and more. Stucco starts failing around 1,500. Roof shingles lose their protective granules at far less than that. A crew running one pressure setting all day will clean your driveway well and damage your house on the same visit, and the damage is not always obvious for weeks.
Soft washing lasts longer
Pressure knocks growth off but leaves the roots in a porous surface, so it returns quickly. A proper soft wash solution kills the organism, which means regrowth takes considerably longer. That is the difference between cleaning a north wall twice a year and cleaning it every few years.
How to tell what a company actually does
Ask what pressure they use on stucco. If the answer is a number above about 1,500 PSI, or if they cannot answer, that is your signal. Ask what they use on a roof. If the word pressure appears at all, keep looking.
Key points
Pressure washing uses force
High-pressure water physically knocks contamination off a surface. It works on dense, non-porous, structurally sound material — concrete driveways, sidewalks, paver patios, block walls, industrial slabs. On the right surface it is fast and effective.
How to tell what a company actually does
Ask what pressure they use on stucco. If the answer is a number above about 1,500 PSI, or if they cannot answer, that is your signal. Ask what they use on a roof. If the word pressure appears at all, keep looking.