Illustrative comparison; not a verified customer job.What K Rend actually recommends
The K Rend maintenance page describes careful cleaning from top to bottom with clean water and a mild detergent on a fan setting, rather than a high-power blast. Its separate advice cautions against applying this approach to dry dash indiscriminately.
Why high pressure is risky
A narrow jet can erode or mark render and drive water into existing defects. The risk increases on damaged, weathered, painted or unsuitable finishes.
When to call a professional
Seek professional help for high walls, unknown render types, extensive algae, cracks, fragile areas or chemical treatments. A proper quote should specify what will and will not be cleaned.
Keep the method compatible with the product
Check your exact render warranty and the latest manufacturer guidance. Never rely on a cleaning setting someone used successfully on a different wall.
Check K Rend’s official maintenance guidance ↗ for your exact render.
Helpful answers from manufacturer and UK industry guidance
Short answers with links to check the supporting guidance.
Is it safe to jet wash K Rend?
Only when the method follows the particular product’s aftercare advice and the surface is sound. K Rend allows a carefully controlled fan-setting wash but warns that very high pressure can damage render. Avoid treating the wall like a hard paving slab.
What pressure setting should be used on K Rend?
There is no single PSI number suitable for every K Rend system. K Rend advises a gentle fan application rather than high power. The contractor should follow the actual finish specification, inspect the surface and test safely instead of relying on a generic pressure setting.
What should I check before pressure washing old render?
Look for hairline cracks, hollow or loose areas, failing seals, staining under sills and signs of water entry. Do not spray an unsound wall with force. A specialist should determine whether gentle cleaning, algae treatment or repair is the first sensible step.
Frequently Asked Questions
Does the manufacturer ban every pressure washer?
No. K Rend permits low-power fan washing on suitable finishes while warning that very high pressure can cause damage.
Can I use a turbo nozzle?
A concentrated high-power nozzle is not consistent with K Rend’s gentle fan-setting guidance.
What if my render is cracked?
Have defects assessed and repaired first; cleaning can introduce water into damaged areas.