Wall Softwashing

The wall softwashing process

1. Inspection

   Walls are inspected first — render, brick, pebbledash, and painted block all behave differently under chemical cleaning, so this step determines what strength of solution the job needs.

2. Solution mixed to the surface

   A sodium hypochlorite solution is mixed to a concentration matched to that surface. Painted or softer rendered walls need a much weaker mix than bare block or pebbledash — a strength strong enough to strip moss and algae off a hardier surface could bleach paint or damage softer render.

3. Low-pressure application

   The solution is applied with a low-pressure sprayer rather than a pressure washer — this is what makes it a "softwash." Growth is killed at the root rather than blasted off, so there's no risk of loosening render, blowing out mortar joints, or driving water behind cladding the way high pressure would.

4. Dwell and rinse

   The solution is left to dwell before being rinsed down. Visible moss and algae typically die back and lift away over the following days rather than being scraped off on the spot — and because spores are killed along with what's visible, the wall stays cleaner for longer than a straightforward pressure wash would manage.

5. Preventative post-treatment

   Once rinsed, a didecyldimethylammonium chloride solution is applied as a long-acting preventative biocide. This doesn't clean anything itself — it's there to delay new moss and algae growth from taking hold, extending the time before the wall needs treating again.