What we found and what we did

What we found and what we did In May 2026 we cleaned a large residential property in Duluth, GA that had a mix of surfaces: a concrete driveway with flagstone edging, flagstone walkways and patio areas, a circular flagstone fire pit surround with a curved stone seating wall, an upper tile deck, and a brick front stoop with stone-capped gate columns. Algae, mildew, and lichen were visible across most of the stone and brick surfaces, particularly on the shaded walkway steps and the gate columns.

The concrete driveway cleaning was straightforward but the flagstone apron at the street required a different approach. On the concrete slab we ran a rotary surface cleaner after a bleach/water/detergent pre-treatment to lift the mildew discoloration. Where the concrete met the flagstone border we dropped pressure and switched to a fan tip so the irregular stone edges and the mortar joints stayed intact. Flagstone and older mortar don't tolerate the same psi you'd run on a plain concrete slab, so we kept moderate pressure across all the stone work throughout the job.

The concrete sidewalk and patio areas included the covered rear patio with its large irregular flagstone floor, the flagstone walkways running alongside the driveway and through the wrought-iron gate, and the circular fire pit patio out back. The steps on the flagside path had heavy algae and green discoloration built up in the joints. We pre-treated with a chemical solution, let it dwell, then worked through each section with moderate pressure. The fire pit seating wall and the stone columns got the same treatment: chemical application, dwell time, then a careful rinse that avoided blasting directly into the mortar lines. On surfaces this age, loose mortar can be exposed by the rinse even when you're being conservative; we noted that possibility before starting so there were no surprises.

The wood deck cleaning covered the upper tile deck with its iron railing and built-in planter boxes. We covered the outdoor furniture before starting and kept the pressure low across the tile surface to avoid shifting grout. A post-treat detergent pass on the tile helped with any mildew residue the initial rinse didn't fully clear.

The brick stoop and gate columns were the last surfaces. Brick tolerates a bit more pressure than flagstone, but the stone caps on the columns kept us conservative there too. The lichen on the column caps was the most stubborn growth on the whole property and got a second chemical application before the final rinse. Duluth gets enough humidity through summer that stone and brick in shaded spots can re-establish algae and lichen growth within a couple of seasons; a zinc-based preventive treatment on the stone surfaces would slow that down between cleanings.

We serve Duluth and nearby. Free estimate, no pressure.

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