Mortar is the glue that binds bricks together, making them one of the sturdiest and most water-resistant construction materials used today. Mortar comes in a wide variety of types depending on where it will be used and is available in many colors to suit your design needs. If you have a fireplace, stone wall or other bricked area with mortar that is not to your liking, there are two basic ways you can change the color of the mortar: applying a muriatic acid to the surface of the brick or re-applying new mortar.
Muriatic Acid
Video of the Day
Step 1
Apply a 10 percent solution of muriatic acid to the mortar with a small paintbrush.
Video of the Day
Step 2
Allow the acid to remain on the mortar for about five minutes or until the acid has stopped fizzing.
Step 3
Rinse the area and allow it to dry to see the color change. Muriatic acid will lighten up the mortar slightly. If the area is not lightened up enough, wait a few days and apply a second coat of acid.
Apply New Mortar
Step 1
Use a chisel and hammer to remove ¼-inch of the existing mortar from between the bricks.
Step 2
Mix up some mortar in a large bucket by following the directions on the package. Once the mortar has been mixed, add a powdered pigment into the bucket to tint the mortar the desired color. Test a few samples of the mixture on a mortar board to determine if the mortar is the desired color before you apply it to your brick.
Step 3
Apply the mortar to the gaps between the bricks with a trowel. Scrape off any excess mortar with the trowel and allow the surface to dry thoroughly. Your mortar should now be a different color to match your design needs.