Soft washing relies on chemistry to do much of the cleaning work, while pressure cleaning relies more heavily on water impact. Neither method is automatically right for every surface. House washing usually favours low pressure, while durable concrete may benefit from controlled higher pressure after pre-treatment.
A knowledgeable operator distinguishes organic growth from other discolouration. Sodium hypochlorite-based solutions are commonly used against mould and algae, but concentration, contact time and surrounding materials must be considered. Rust, bore-water staining, oxidation, efflorescence, paint failure and oil contamination need different treatments. Increasing pressure is not a safe substitute for identifying the stain.
Customers should also be cautious of promises that every mark will disappear. Existing paint breakdown, etched concrete and permanent pigment changes can remain after the contaminant has been removed. A written scope should state which surfaces are included, the proposed cleaning method, how access and runoff will be managed, and any marks that may require separate treatment.