Pressure & Soft Washing

Charleston's heat and humidity don't just grow plants. They grow mold, algae and mildew on every exterior surface a property has — driveways, siding, roofs, parking lots, sidewalks — often within a season of the last cleaning. That growth is not only unsightly; left alone, it starts breaking down the material underneath, whether that is a concrete slab or the paint sealing a board of siding.

Driveways, parking lots and sidewalks are built to take force, so pressure washing is the right tool on them. Oil, mold and algae work into the pores of concrete and asphalt and, given enough seasons, weaken the surface rather than just discolor it. High-pressure water strips that buildup back to sound material — which is also why it is the wrong tool almost everywhere else on a property.

Siding, roofs and painted trim cannot take that same force. Hardieplank cracks, paint chips, and water gets driven behind the cladding with no way back out. Soft washing solves the same growth problem with a cleaning solution and low pressure instead of raw force. Because the solution kills the organism instead of blasting the growth off the surface, what comes back grows in slower.

Roof cleaning follows the same logic. Those black streaks running down an asphalt shingle roof are algae colonies, not soot, and they work into the granule coating if left alone. Blasting a roof with pressure strips away the granules faster than the algae ever would. A soft wash lifts the growth and the staining without shortening the life of the shingles.

Commercial properties split the same way. Restaurant patios, storefronts and parking lots get pressure washed, since the surface is built for it and grease and tire marks need real force. Downtown, where rowhouses were laid up in lime mortar, the opposite holds — pressure pulls soft mortar right out of the joints, so that brick gets soft washed instead.

Under Mount Pleasant's oak canopy, growth comes back fast — shade holds moisture, salt air off the barrier islands holds grime. The point of choosing pressure washing for one surface and soft washing for another is keeping a property looking actually clean, not just freshly rinsed.