How to Apply Protectant on Outdoor Slate Tile

Sweep the outdoor slate tile with a soft-bristle broom to remove any loose dust, dirt and debris from the tile.

Fill a bucket with 1/2 cup of mild soap and 1/2 gallon of warm water. Stir the soap mixture with a mop. Wear latex gloves to keep your hands clean and dry.

Wring out excess moisture and mop the tile with the wet mop to remove any caked-on debris. Rewet the mop, wring it out and continue mopping the tile until it is clean. Let the slate tile air-dry. Dry any crevices with a large towel.

Fill a paint tray with a water-based polyurethane slate tile sealer. Wear a nose mask to keep the sealer’s fumes out of your lungs.

Use a paint roller with an extension rod to roll one thin coat of polyurethane sealer onto the slate tile. Use a paint brush to apply the sealer to areas the roller can’t reach.

Allow the first coat to dry completely, for at least two hours. Repeat Steps 4 and 5 to apply a second coat. Let the outdoor slate tile dry for 24 hours after applying the second coat before walking on the tile.