Soft Washing Benefits over Power Washing. Soft wash is less likely to damage siding and wood, or leave permanent marks on concrete, brick and stone. Soft wash kills algae, mold, and mildew instead of just blasting it off, keeping the surface clean and clear of discoloration longer. Soft washing not only keeps your home looking beautiful, but it also increases your roof and house's lifespan, saves energy, and is eco-friendly. Most importantly, soft washing kills harmful bacteria, keeping you and your family happy and healthy.