What render cleaning typically costs
Render cleaning is normally priced per elevation or per property rather than by the hour. As budgeting guidance, a soft wash on a standard three bedroom house commonly lands somewhere in the region of 300 to 700 pounds, with larger houses, three storey elevations and commercial buildings above that.
Access, wall area and the density of the staining are the three variables. A bungalow reachable from ground level on every side is the cheapest case, and a tall gable over a narrow side passage is the most expensive.
Soft washing explained
Soft washing is a low pressure process. A cleaning solution is applied evenly across the render, left to dwell so it can work through the algae and organic film, then rinsed off at low pressure. Because the chemistry does the work, the wall is never subjected to the force that opens up a rendered surface.
Dwell time is the part people underestimate. Application and dwell time are matched to the surface, and rushing that stage is what produces patchy results.
Why not a pressure washer
A pressure washer on render can scar the surface, drive water into the wall, open up hairline cracks and strip the thin coloured outer layer on some systems. The damage often shows up as banding or lighter patches that no amount of later cleaning will even out.
There is a second problem. Pressure removes the visible growth without treating what is left behind, so the green comes back quickly and looks worse than before.
How long the result lasts
On a treated wall in reasonable conditions, expect the clean appearance to hold for a couple of years or more before growth becomes noticeable again. Shaded, north facing and heavily planted walls green up sooner, and coastal moisture shortens the interval too.
Trimming back planting that keeps a wall damp, and making sure gutters and downpipes are not discharging onto the render, does more for longevity than anything applied to the surface.
Preparation and protection
Good render cleaning includes protecting what is around the wall. Windows, doors, paving, planting and any adjacent surfaces are covered or wetted down before the treatment goes on, and the area is rinsed afterwards. Careful protection of nearby surfaces is part of the process rather than an extra.
A note on the figures
Figures on this page are typical UK guidance ranges to help you budget, not a quotation. Every price depends on the surface, the access and how heavy the soiling is, so ask for a written figure for your own property.