How to apply waterproof silicone to masonry

Updated February 21, 2017

Masonry refers to brickwork or blockwork. Bricks and blocks are the foundation of many homes or buildings. Buildings are built from the ground up, beginning with the block. Most houses have brick walls with some type of siding over them. While these materials are built for the outdoors, sealing them will help them last longer. Applying a waterproof silicone sealer to a masonry wall will help enable it to last longer and better deal with the outdoor elements.

Clean the bricks thoroughly and remove any dirt, mould, moss, grease, debris or other material on the masonry wall of your home. Spray the entire surface with a garden hose. Move over the area and get closer to the wall to spray off tougher stains. Let the area dry, until the wall is not visibly wet or wet to the touch.

Put a tube of exterior silicone sealant into a caulk gun and press it down firmly into place. Cut off the tip of the nozzle on the caulk gun with a utility knife. Pull the trigger and cover all gaps or cracks between the brick with the silicone sealant. Cover all the visible seams and wait one hour for the silicone to harden and dry into place on the wall.

Open a bucket of silicone waterproofing sealer and apply it to the masonry wall with a paint roller. Move back and forth from side to side with the roller in a W pattern to prevent streaks. Go across the entire surface with an even, thick coat. Wait two hours for the first coat to dry.

Apply a second coat the same way the first one was applied and let it dry overnight. Inspect the area and verify the sealer is covering the entire masonry wall. Add a third coat, if necessary, for better coverage.


There are other ways to apply the waterproofing, such as with a paint brush or spray gun, depending on how big of an area you are covering.


Always be careful when working on a ladder. Make sure it is stable and on steady ground.

Things You'll Need

  • Garden hose
  • Exterior silicone sealant
  • Caulk gun
  • Utility knife
  • Silicone waterproofing sealer
  • Paint roller
  • Ladder
Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Alexander Callos began writing in 2005 for "The Lantern" at The Ohio State University and has written for various websites, including Bleacher Report, Top Ten Real Estate Deals and Columbus Sports. He has published articles for CBS Sports, and other websites. He graduated in 2007 from The Ohio State University with a bachelor's degree in public affairs journalism.