Aggregate Walkway:
Blackened Stone to Like-New.

Aggregate and concrete take pressure well, so this was a direct pressure wash rather than a soft wash — but the technique still matters. We work the surface evenly to avoid streaking or leaving lighter and darker patches, and finish with a post-treatment application that slows algae from re-establishing as quickly as it would otherwise.

What was happening

Exposed-aggregate surfaces are porous by design — that texture is what gives them their look, but it also gives algae and grime plenty of surface area to grip onto. Shaded, tree-covered walkways like this one rarely dry out fully between rains, so the buildup compounds year after year until the surface reads as solid black instead of stone.

Our approach

Aggregate and concrete are durable surfaces that can handle significantly more pressure than delicate materials, making a direct pressure wash the right approach for this walkway rather than a soft wash.

We began by pre-treating the surface to kill and loosen the moss and organic growth, helping make the cleaning process more effective. We then used a professional surface cleaner to evenly clean the entire walkway and produce a consistent, uniform finish without leaving visible pressure marks.

After the main cleaning, we used a pressure washing wand for detailed touch-ups, including cracks, edges, and areas the surface cleaner could not fully reach. We finished with a post-treatment application designed to help slow the return of algae and organic growth, keeping the walkway cleaner for longer.