River rock is similar to pea gravel, consisting of tiny pebbles of different colors. It is installed on pathways, pool decks and other outdoor patios areas. The pebbles are bound together with an epoxy resin material that hardens when dry. Over time, this epoxy wears down and must be reapplied to maintain the floor. Homeowners can reseal river rock themselves as long as the rocks are clean and dry.
Apply chlorine bleach to mold and mildew spots in the river rock. Scrub the areas with a stiff-bristled brush until they are gone. If there are any white spots, which are typically lime buildup, apply a lime remover product and scrub until they are gone.
Fill a pressure washer with a mixture of water and 10 percent bleach. Clear all furniture or other items off the river rock.
Turn on the pressure washer and clean the river rock thoroughly, using a side-to-side, sweeping motion. Keep the tip of the pressure sprayer nozzle at least 12 to 24 inches away from the rock to prevent dislodging loose rocks. Allow the river rock to dry for at least two to three days and more if needed. The rock must be absolutely dry before resealing it or you will trap moisture and cause it to deteriorate.
Fill a 1-gallon bucket with three parts of epoxy resin and one part curing agent. Mix the two thoroughly, using a paint stirrer.
Pour the mixture into a paint tray and dip a paint roller into it. Roll the epoxy sealer onto the river rock surface in side-by-side strokes, working your way across it until you have covered all of it. Allow the epoxy to dry for 24 hours before walking on it or replacing any furniture.