Can K-Rend be pressure washed?
The short answer is no. K-Rend is a through-coloured silicone render with a deliberately textured surface, and high pressure removes the staining by taking part of that surface away with it.
The damage is permanent. Once the texture has been eroded there is no cleaning process that restores it — the options are living with it, painting over it, or re-rendering.
What pressure washing damage looks like on render
It is easy to recognise once you know what you are looking at, and it usually appears within days as the wall dries down.
- Lighter patches where more of the surface has been removed than elsewhere
- Straight lines or arcs matching the path the lance was swept in
- A rougher, duller texture that then attracts dirt faster than the untouched wall
- Clean stripes above and below where the operator could comfortably reach
- Water pushed in behind beads, movement joints and around window frames
Why the finish reacts that way
The colour in K-Rend runs through the material rather than sitting on top like paint, which is one of its advantages. But the outer face still carries the texture that gives the wall its appearance, and that face is the part a pressure washer attacks first.
Eroded render is also more absorbent. A wall that has been aggressively washed tends to green up faster next time, because there is more surface area holding moisture.
What is used instead
Render is soft washed. A cleaning solution is applied at low pressure, left to break down the algae and organic growth, then rinsed evenly across the whole elevation so the wall dries consistently rather than in patches.
It takes longer than blasting a wall, and that is the point — the surface is left doing the job it was built to do.
If your render has already been pressure washed
Say so when you get in touch and send photographs. Organic staining on the undamaged areas can still be treated, but marks left by a lance will not come out, and it is better to know that before anyone quotes you for a clean.
Want it looked at properly?
Send a few photographs of the elevation along with the address, and Rob will tell you what can realistically be improved, what it will cost and when it can be done.