Why this usually happens
Moisture and shade let algae and mildew take hold.
Pollen, dust, and pollution film give it something to feed on.
Vinyl, aluminum, stucco, and brick all collect it over time.
Why you should not ignore it
Beyond looking dirty, organic growth holds moisture against your siding, which can degrade the surface and work into seams. Mildew and mould can affect air quality near windows and entries, and the longer staining sits, the harder it is to remove.
Durham Region homes see this buildup on vinyl, brick, aluminum, stucco, trim, and shaded foundation walls. It is often most visible beside gardens, under trees, on the side of the home that receives the least sunlight, or near surfaces where moisture lingers after rain. The staining can look cosmetic at first, but it usually points to organic material holding moisture against the exterior.
What to do next
- Do not blast it with a pressure washer — high pressure forces water behind siding and can crack or dent panels.
- The safe, effective method is soft washing: low pressure plus a cleaning solution that kills the growth and washes it away, rather than just spraying the surface.
A safe exterior cleaning approach
Our house soft washing safely removes algae, mildew, and grime from siding, brick, and stucco — restoring your home's appearance without the risks of pressure washing. Serving Durham Region.
Related DSS services and local pages
Frequently asked questions
Is soft washing safe for vinyl siding?
Yes — it's the recommended method; pressure washing can damage siding.
Will it kill the growth or just rinse it off?
Soft washing treats it at the source, so it stays clean longer.
How often should siding be cleaned?
Every 1–2 years for most homes, sooner on shaded sides.