Removing Old Grout

• 1). Use a grout saw to remove the old grout. Apply pressure and run the grout saw back and forth over the grout lines. Remove at least two-thirds of the existing grout. Any grout around the edges of the joints that cannot be removed with the grout saw should be removed with a hammer and chisel. Gently tap the chisel with the hammer to break away the grout.
  
  
• 2). Vacuum up the dust and debris created from sawing out the old grout. Use the hose attachment on your vacuum cleaner to thoroughly vacuum the tile joints.
  
  
• 3). Mix a solution of equal parts chlorine bleach and water in a bucket. Dip a rag into the bucket and wring it out well.
  
  
• 4). Scrub the tile joints well with the bleach solution. This will kill any mildew or fungus growing in the joints.
  
  
• 5). Allow the joints to dry completely.
  
  

Applying New Grout

• 1). Mix up a batch of grout into a bucket according to the manufacturer's instructions. If you prefer, a premixed grout may also be used.
  
  
• 2). Scoop a generous amount of grout from the bucket using a grout float. Spread the grout into the joints of the tile. Hold the grout float at a 45 degree angle and use circular motions to force the grout into the joints.
  
  
• 3). Run the grout float back and forth over the joints several times to thoroughly pack the joints with grout. Remove excess grout from the tiles by holding the grout float on its edge, running it over the tiles and scooping up the excess grout.
  
  
• 4). Allow the grout to harden in each joint for about five minutes. Use a damp sponge to wipe excess grout off the face of the tiles. Follow up by running a dry rag across the tile, taking care not to disturb the wet grout.
  
  
• 5). Allow the grout about 20 minutes to completely set. It will take about 24 hours for the grout to completely cure.
  
  
• 6). Apply a grout sealer to the grout. Follow the manufacturer's instructions for applying the sealer as this will vary among products.