The single most important thing to understand before you book: which surfaces get a low-pressure soft wash and which can take high pressure, why the wrong choice strips paint, gouges render and cracks tiles, and how a good cleaner decides.
Short answer: soft washing cleans with chemistry and low pressure, so it is safe on render, paint, roofs, timber and solar. High-pressure cleaning cleans with force, which is right for concrete and driveways and wrong for almost everything else. The single most important thing to understand before you book is which surface gets which, because the wrong choice is how homes get damaged.
Soft washing applies a surface-safe detergent at low pressure, lets it dwell so it kills the mould, lichen and algae, then rinses it away. The growth is treated at the root rather than blasted off the surface, which is why it does not green up again in a few weeks. It is the standard method for any surface that force would damage.
High pressure uses water force to lift grime, and on the right surface it is exactly the tool. Concrete, driveways, paths and pavers are built to take it. The trick even here is using a rotary surface cleaner for even passes rather than a hand wand that leaves stripes, and pre-treating oil and rust rather than just blasting harder.
This is the Surface and Method Sheet we put in writing on every job. It is the whole argument in one place.
If someone offers to high-pressure clean your render, paint or roof, that is not a cleaning method, it is the damage you are trying to avoid. Ask for soft wash on those surfaces by name.
It is not a guess. A careful operator walks the property, identifies each surface and its condition, and gives you the method, the pressure and the reason for each one, then proves it with a test patch on an inconspicuous spot before committing to the whole job. If a quote is a single number with no method named, you have no way to tell whether your render is about to be stripped.
Brisbane humidity and tree cover mean a lot of mould, lichen and black streaking, especially on shaded walls and roofs. That is exactly the growth soft washing is built to treat, and exactly the surface a high-pressure gun will ruin. Matching the method to the surface is not a premium upsell here, it is the difference between a clean that lasts a year and a repair bill.