How to Make Slate Floor Grout Lines Look Contemporary

Sweep the floor with a stiff-bristled broom to remove any dirt or debris. Collect the debris in a dustpan and bag it for disposal.

Fill a bucket with one gallon of hot water. Add a cup of oxygen bleach powder and stir the mixture with a stirring stick until the power dissolves. Pour the bleach mix onto the floor, covering all grout lines with the liquid. Keep any remaining bleach mix in the bucket for further use. Wait 30 minutes after application for the bleach to penetrate the grout.

Scrub the bleach into the grout using a toothbrush. Examine the toothbrush often for signs of dirt. Remove the dirt by rinsing the brush in a bucket of clean water. After rinsing, swish the brush through the bucket of bleach mix before continuing to scrub the grout lines.

Rinse the bleach mix from the floor using a mop and hot water after scrubbing the grout clean. Wait for the floor to dry, then examine the grout lines for further signs of dirt. Spot clean any dirty sections with the toothbrush and bleach, then wipe off the bleach with hot water and a damp sponge. Wait an hour or two for the floor to dry.

Line the edges of the tiles in masking tape to protect the tiles from staining as you color the grout.

Cover the surface of the grout with grout stain in the color of your choice, using a small paintbrush. Apply the stain in a light layer, then wait for the stain to dry. Drying times depend on the brand of stain used; read the manufacturer's instructions for suggested drying times.

Examine the grout color after drying. If the grout is too light, then apply another layer of the stain. Remove the tape when finished and wait for the stain to dry completely before using the floor.