Silicone renders such as K-Rend are sold as self-cleaning, and for the first years they largely are. Once the surface has weathered and airborne growth gains a hold, that same textured face becomes very good at keeping algae.
Why it goes green anyway
The hydrophobic surface sheds water but still collects spores, dust and pollen in its texture. On a shaded elevation that is enough to establish a colony.
This guide sits under our Wall Cleaning & Softwash work, covering 20-mile radius of Plymouth.
What not to do
High pressure on silicone render damages the face and can leave permanent banding where the lance travelled. Once that texture is opened, the self-cleaning behaviour is gone for good.
The safe method
Low-pressure biocide, dwell, gentle rinse. Panel by panel, working the whole elevation so there is no visible join between treated sections.
Questions we get on this
- Will cleaning void my render warranty?
- Softwash in line with the manufacturer's guidance should not. Pressure washing frequently does - check your documentation.
- Can coloured render fade from treatment?
- Not from a correctly diluted softwash. Uncontrolled bleach is a different story.
- How often does K-Rend need it?
- Typically every few years on shaded elevations, longer where it gets sun and airflow.
Related reading
- uPVC cladding, fascias and soffits
- Indian sandstone patios: cleaning without blotching
- Porcelain paving: low maintenance, not no maintenance
- Solar panels, roof access and cleaning around them