Glossary
Surfactant
Definition
A surfactant is a soap-like additive that lowers surface tension so a cleaning solution clings to vertical surfaces, spreads evenly, and stays wet long enough to work.
In soft washing, a surfactant does two jobs. It thickens the mix so it sticks to siding and roofs instead of running straight off, and it helps the solution wet into porous surfaces and break the grip of algae and grime.
Most pros add a dedicated soft-wash surfactant to their sodium hypochlorite mix, often one that also masks the chlorine smell. Use too little and the solution sheets off before it can dwell; use too much and you waste product and create excess foam.