Roof Soft Washing, Step by Step
A roof soft wash kills moss and algae with a cleaning solution applied at low pressure. The crew checks the roof, wets and protects the plants below, brushes heavy moss off by hand, applies the solution, lets it work, then rinses and clears the gutters. On a typical house it costs $550 before GST.
It is less dramatic to watch than a pressure washer, so it helps to know what each step is for and what a proper job looks like.
Setup, inspection and protection
A proper job starts on the ground. The crew inspects the roof to confirm the material, pitch and how much growth there is, and checks access and safety. Landscaping around the downspouts and below the work is pre-wetted and, where needed, protected, because the treatment rinses down and off the roof.
Loose debris and heavy moss cushions are cleared first, by hand and brush where the growth is thick, so the treatment reaches the roof surface itself.
Treatment and dwell
The soft-wash solution, a biodegradable detergent, is applied evenly at low pressure across the roof. Then it dwells: it is left on long enough to kill the moss, algae and lichen down to the root. This dwell time is the part that makes soft washing work, and it is why the method is chemistry-led rather than force-led.
The solution is applied carefully so it covers the growth without pooling or running off before it has done its job, and adjacent surfaces and plants are rinsed as needed throughout.
Rinse, and the weeks after
Depending on the roof and the product, the roof is gently rinsed, or the rain is left to do the final rinsing over the following weeks. This is the part that surprises people: a soft-washed roof often keeps getting cleaner for weeks after the crew leaves, as the dead growth releases and washes away.
Because the moss and algae are killed at the root rather than blasted off, the roof stays clean for years, not months. That lasting result, not a dramatic same-day before-and-after, is the point of soft washing.