How to Seal Cinder Block Walls

Breeze block walls are common around your home, particularly in the basement, foundation or retaining walls. These walls are often porous and subject to abuse from water. Sealing breeze block walls can help prevent water from soaking into them and allowing moisture to enter your home. Many types of sealants are available at home supply centres for the home. You can seal the breeze block wall with sealant or paint depending on the location of the wall and your preference.

Clean the wall with a mild soap and water solution. Use a sponge to remove all the dirt and grime on the wall. Allow the wall to dry thoroughly.

Patch holes or cracks in the wall with concrete patch. Use a putty knife or trowel to cover all the areas that you will be unable reach when sealing the wall.

Use a rough-style paintbrush to apply sealant or paint to the breeze block wall. Brush the sealant on using short strokes to ensure you cover the wall properly. The sealant or paint should be fairly thick, taking more time to dry.

Allow the first coat to dry and cure for 24 hours. Apply a second coat if necessary to ensure full coverage of the wall.


Consider adding a layer of insulation around the external side of the breeze blocks with either foam pieces or plastic sheathing. Although this may require some digging or excavation, it may help protect your home from further water seepage. For new constructions, ask your builder about adding foam insulation inside the breeze block wall to increase the thermal resistance. In this manner, you can finish a basement or home addition later and have an area that feels warmer than an area ringed by uninsulated breeze blocks, according to the U.S. Department of Energy.


Do not paint in enclosed areas. Open up windows or garage doors to ensure proper ventilation when painting.

Things You'll Need

  • Mild soap solution
  • Bucket
  • Sponge
  • Concrete patch
  • Sealant or paint
  • Brush
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About the Author

Daniella Lauren has worked with eHow and various new media sites as a freelance writer since 2009. Her work covers topics in education, business, and home and garden. Daniella holds a Master of Science in elementary education and a Bachelor of Arts in history from Pensacola Christian College.