Quick Answer Cleaning and sealing serve different purposes and work best together: cleaning removes existing dirt, stains, algae, and grime from the surface, while sealing creates a protective barrier that keeps new stains, water, and freeze-thaw damage from penetrating the concrete afterward. Sealing without cleaning first traps existing stains underneath the sealer, so cleaning should always come before sealing, not instead of it. What Concrete Cleaning Does Concrete cleani

Quick Answer Green discoloration on concrete is usually algae feeding on moisture and organic debris, while black or dark gray patches are typically mold or mildew growing in shaded, damp areas of the slab. Both thrive in low-sunlight spots like under porches, near downspouts, or beneath dense tree cover, and both can be removed with the right cleaning solution and pressure washing. Green Stains: Algae Growth Green discoloration on driveways and walkways is almost always alga

Quick Answer Fresh oil stains can often be lifted with dish soap, baking soda, or a degreasing concrete cleaner and a stiff brush. Older, set-in stains usually need a professional-grade degreaser and hot water pressure washing to fully break the oil out of the concrete's pores. The longer a stain sits, the deeper it soaks in, so treating it quickly makes a big difference. Why Oil Stains Are So Stubborn on Concrete Concrete is porous, which means oil doesn't just sit on the su