When it comes to treating moss, algae, and lichen on exterior surfaces, not all products work the same way.
Two of the most commonly used approaches are sodium hypochlorite-based cleaners (such as Hypastat ≥16%) and traditional moss treatment formulations.
While both can be effective, they are designed for very different purposes.
Hypastat - A cleaner and sanitiser
Hypastat is a high-strength sodium hypochlorite solution (≥16%), designed primarily as a cleaner and sanitiser. Its mode of action is rapid and aggressive. When applied correctly, it works by:
- Oxidising organic material
- Breaking down moss, algae, and lichen quickly
- Visibly cleaning surfaces in a short time frame
This is why Hypastat is commonly used where:
- Immediate visual results are required
- Surfaces need to be cleaned prior to sealing or coating
- Organic staining needs to be removed quickly
On surfaces such as:
- Masonry
- Concrete
- Oamaru stone walls
Hypastat can effectively "burn off" biological growth and restore a cleaner appearance, making it ideal for preparation work before sealing or further treatment.
Traditional moss treatments - Control rather than clean
In contrast, traditional moss and lichen treatments (such as non-oxidising soft wash systems) are designed to kill and control growth over time, rather than clean instantly.
These products typically:
- Target biological growth at a cellular level
- Do not rely on oxidation
- Work more gradually
- Allow moss and lichen to die and weather away naturally
This approach is often preferred when:
- Long-term control is the goal
- Surface preservation is important
- A non-aggressive treatment is required
- Minimal visual disruption during application is desired
Key difference: Immediate cleaning vs long-term control
The simplest way to understand the difference is:
Hypastat (sodium hypochlorite)
→ Fast-acting cleaner and sanitiser
→ Immediate visual results
→ Ideal for surface preparation
Traditional moss treatments
→ Slower-acting biological control
→ Longer-lasting effect
→ Ideal for ongoing maintenance and protection
Choosing the right approach
The best product depends on the job:
- If you need to clean and prepare a surface quickly (for example before sealing masonry or stone), Hypastat is often the right choice.
- If you want to control moss and lichen over time with a more surface-friendly approach, a traditional treatment may be more suitable.
In many professional situations, both approaches are used together - with hypochlorite for initial cleaning, followed by a treatment system for ongoing control.
Hypastat is a powerful, professional cleaning solution that delivers rapid results when used
correctly. However, it serves a different purpose to traditional moss treatments.
Understanding the difference allows you to choose the right method for the surface, the level of growth, and the desired outcome - whether that's instant cleaning, long-term control, or both.
So......
- for cleaning masonry & pavement prior to sealing, where a fast visual result is required - Use Hypastat
- for long term control & maintenance of building surfaces and protection from moss, mould, lichen and liver wort - Use Agent Blue