Why does my roof keep getting cleaner for weeks after a soft wash?

Because the soft wash treatment kills the growth rather than blasting it off. Most moss and mould rinses away on the day, but heavily stained or lichen-covered tiles keep brightening for several weeks as the dead growth dries out and weathers away with rain and sun.

What happens after the clean

On the day, you’ll see most of the dirt, moss and mould gone. Lichen and deep staining often look lighter but not completely gone. Over the next few weeks, the dead growth loosens and is washed off by rain and wind, and the roof keeps improving.

Is that normal?

Yes. It’s a sign the treatment has worked at the root rather than just removing the top layer. It’s also why soft washing tends to give longer-lasting results than high-pressure cleaning.

What if it rains straight after?

Light rain after a clean is fine and can even help rinse away loosened growth. We schedule work around heavy storms so the treatment has time to work.

Can I do a treatment first and clean later?

Yes. Some customers like a treatment first, then a full clean a few weeks later once the growth has died off. Ask about this when you request a quote.

Related services: Soft Washing · Moss Prevention Cleaning