Concrete blocks are surrounded by grout so the sealer used needs to be approved for use on concrete and other cement-based materials.

Block walls are found in a variety of applications including retaining walls and basements. The application will be a direct indicator of which product needs to be used.

Retaining Walls & Buildings

It is impossible to maintain a paint or coating on the exterior of a building which is why water repellents are used to seal retaining walls and building exteriors. Water repellents are designed to fill in the pores and prevent water from being absorbed in the block on the surface. This action will also stop issues such as freeze-thaw damage, efflorescence, and the growth of mold and mildew. Most DOT applications require the use of a silane-siloxane blend because of the performance abilities and expected life span. Silane-siloxanes do not change the look of the block but they will work to protect the block and the grout for 25+ years.

• SX5000 – This silane-siloxane blend by Foundation Armor is available in a water and solvent based formulations. They offer a 10%-100% solids formulations and serve many DOT nationwide.
• Sure Klean – This silane-siloxane blend by Prosoco is available as a water based formulation only. They offer a low solids formulation with a 1 year warranty.
• S20 – This silane-siloxane blend by Okon is available as a water based formulation only . They offer two low solids formulations with a 1 year warranty.

Basements

Silane-siloxane blend sealers, and sodium silicate based products are used to waterproof concrete block basements. If an aesthetic enhancement or paint is desired, one of the following products should be used:

1. PPG Architectural Coatings – This product is more than just a coating, is a premium interior/exterior, light weight, acrylic latex block filler and surface. It bond to the concrete from within the pores.
2. Krylon Block Filler – Like with the PPG Coatings, the Krylon Block Filler is designed to bond to the surface and fill in the blocks.
3. KILZ Block Filler – KILZ also offers a block filler designed to bond to the surface and fill in the blocks.