Lichen and moss on roofs: the spray-and-leave method
Lichen and moss staining on tiles often stays after a wash. HydraBio is a spray-and-leave concentrate you apply on its own, on a clean dry roof, and leave on.
Before you start
- Pick a dry day with no rain forecast for 24 hours.
- Gloves and eye protection on.
- Keep it out of ponds, dams, pools, fish tanks and gutters that drain to them: it is very toxic to aquatic life.
- Cover plants you don’t want sprayed.
- Tell the customer: results are gradual, over weeks to months, not the same day.
The method
- Clean the roof first and let it dry. Wash off loose dirt and growth, rinse thoroughly, and let it dry. Detergent residue cancels HydraBio out, so rinse all soap off.
- Mix it. 1:9 for most jobs (1 L HydraBio + 9 L water), 1:7 for heavy lichen, 1:14 as a maintenance coat after a wash. Mix fresh and use it the same day. Use a sprayer or tank rinsed clean of soap and chlorine.
- Protect plants and anything run-off could reach.
- Apply bottom up and soak the growth. Coverage matters more than strength.
- Leave it on. Don’t rinse. The growth loosens over the following weeks and the weather carries it off over the months after.
- Heavy lichen: a second application after 4 to 6 weeks, at 1:7 for a faster result.
About 125 to 150 L of mix does an average double-storey home.
Don’t mix
Not with HydraWash or other detergents, chlorine or sodium hypochlorite, or acids. They cancel it out.
Troubleshooting
- It rained the same day. It may have washed off. Reapply on the next dry day.
- Nothing seems to be happening. That’s normal for the first weeks. Heavy lichen may need a second application.
- Applied straight after washing. Soap residue cancels it out. Rinse, let it dry, reapply.