Why North-Facing Walls Develop Growth in the Desert
Arizona's intense sun exposure on south and west-facing walls typically kills biological growth before it can establish, but north-facing walls receive minimal direct sunlight and retain moisture from irrigation overspray, monsoon rainfall, and morning dew significantly longer. This combination of shade and retained moisture creates ideal conditions for mold, mildew, and algae to take hold — visible as dark streaking or a greenish-black tint on stucco, block, or siding.
Homes with mature landscaping or shade structures near north-facing walls see this issue more frequently, since the additional shade further extends how long moisture lingers on the wall surface.
Professional Soft Washing Removes Growth Safely
High-pressure washing alone often fails to fully address mold and mildew because it can spread spores without killing the root organism, and on stucco, excessive pressure risks surface damage. Professional soft washing applies biodegradable algaecide and mildewcide solution at low pressure, allowing it to dwell and kill the organism at the root before a low-pressure rinse removes the dead growth and residue.
Blues Home Services treats north-facing wall growth throughout the Phoenix metro using appropriate soft-washing chemistry for each surface type. Call (480) 901-4768 for a free estimate.