Protecting concrete blocks from water intrusion is essential for basements, foundations, and outdoor structures. This guide presents effective waterproofing solutions across sealants, penetrating treatments, and water-repellent coatings. Each product below is selected for durability, compatibility with concrete blocks, and long-term performance in American conditions.
| Product | Brand | Key Benefit |
|---|---|---|
| Liquid Rubber Basement And Foundation Repair Sealant (5 Gal) | Liquid Rubber | Permanent waterproof membrane with high elongation for leaks and moisture |
| RadonSeal Standard Concrete Sealer, Deep-Penetrating (5 Gal) | RadonSeal | Deep penetration for basement walls, slabs, and radon mitigation |
| CHIMNEYRX Advanced Water Repellent | CHIMNEYRX | Breathable polysiloxane sealant for masonry surfaces |
| Concrete Sealer Clear Penetrating Waterproofing Spray | Black Diamond Stoneworks | Durable, water-based penetrating seal with natural look |
| Stormdry Brick Sealer | Stormdry | 25-year protection against penetrating damp on masonry |
Liquid Rubber Basement And Foundation Sealant – 5 Gallon
Brand: Liquid Rubber. This flexible sealant forms a permanent waterproof membrane suitable for basement waterproofing, foundation leak repairs, shower liners, and planter boxes. It offers up to 900% elongation, helping to seal active leaks and moisture. The formula is designed as a complete basement waterproofing system, capable of sealing against moisture and compatible with self-leveling concrete. It also functions as a versatile concrete crack filler that remains flexible across temperature changes, ensuring long-term protection on concrete, masonry, wood, metal, and foundation surfaces. Ideal for DIY projects seeking professional-grade results.
RadonSeal Standard Concrete Sealer, Deep-Penetrating (5 Gal)
Brand: RadonSeal. This deep-penetrating sealer penetrates concrete below the surface to block pores, reducing water intrusion, moisture vapor, and efflorescence. It is suitable for basement walls, foundation walls, slabs, crawlspaces, and poured concrete. The product also functions as a concrete densifier to strengthen surfaces, decreasing dusting, cracking, and wear from freeze-thaw cycles. It is designed to be permanent with no reapplication, offering resistance to hydrostatic pressure and sustained protection as part of the structure.
CHIMNEYRX Advanced Water Repellent
Brand: CHIMNEYRX. This breathable masonry sealer uses a polysiloxane formula to deeply penetrate brick, stone, and concrete, forming a barrier that repels water while letting moisture escape. It can be applied over existing outdoor sealers and works as a versatile spray sealer for residential and commercial projects. The product is suitable for use on concrete, brick, and chimney surfaces and aims to prevent water damage without sacrificing the natural look of the masonry.
Concrete Sealer Clear Penetrating Waterproofing Spray
Brand: Black Diamond Stoneworks. This commercial-grade water-based sealer protects concrete surfaces from water, salt, and weather damage. It reduces moisture intrusion to prevent cracks, spalling, and stains, making it suitable for driveways, patios, pavers, brick, grout, stucco, and natural stone. The finish tends to preserve a natural look while offering durable resistance to outdoor elements, keeping concrete blocks less susceptible to moisture-related issues over time.
Ion-Bond Armor Industrial Concrete Sealer – 5 Gal
Brand: RadonSeal. This industrial-grade siloxane sealer penetrates up to 2 inches into concrete, brick, or masonry, providing deep protection. It is designed to seal against negative-side water pressure and is intended to be permanent with no reapplication required. The product aims to deliver long-lasting waterproofing for basement walls, crawlspaces, garage floors, and other concrete blocks subjected to moisture and hydrostatic pressure.
Americrete A-1300 Clear Glossy Concrete Sealer
Brand: Americrete. This non-toxic, environmentally friendly sealer offers a glossy finish while providing penetration-based waterproofing. It resists yellowing and protects concrete surfaces from water, grease, oils, acids, stains, and salts. The sealer is suitable for interior and exterior use on floors, driveways, garages, cinder blocks, sandstone, sidewalks, and similar cement surfaces, helping to maintain a clean, glossy appearance with durable moisture protection.
Stormdry Brick Sealer
Brand: Stormdry. This clear brick, stone, concrete, and masonry waterproofer provides 25-year protection against penetrating damp. It forms a breathable barrier that allows masonry to dry naturally while maintaining thermal properties. The product is suitable for entire masonry assemblies and aims to deliver long-term protection against damp and moisture intrusion in basements and exterior walls.
Buying Guide
Key considerations when selecting a concrete block waterproofing solution include:
- Penetration depth and type: Deep-penetrating sealers can strengthen the concrete from within, while surface sealers protect the exterior face. For basements and crawlspaces, deeper protection is often preferred to combat hydrostatic pressure.
- Breathability: Choose breathable formulations to allow moisture vapor to escape, reducing the risk of trap moisture and efflorescence.
- Flexibility and durability: Elastomeric and rubberized coatings accommodate concrete movement and temperature changes, reducing cracking and delamination.
- Surface compatibility: Ensure the product adheres to concrete, masonry, stone, brick, and wood where needed. Some products are multi-surface, while others are specialized.
- Indoor vs. outdoor use: Indoor applications (basements, crawlspaces) may require low-odor or low-VOC formulas; outdoor surfaces demand weather resistance and UV stability.
- Longevity and maintenance: Permanent or long-lasting options minimize reapplication, but some may require periodic reapplication in extreme conditions.
- Radon mitigation compatibility: If radon mitigation or soil gas issues exist, consider products with penetrating properties designed to seal pores effectively.
- Finish and aesthetics: Some sealers impart a slight gloss; others leave a natural or matte look. Consider appearance goals for finished spaces.
- Application method: Sprays, brushes, rollers, and trowel-applied coatings each have pros and cons depending on surface area and accessibility.
Selecting the right product depends on the specific conditions of your blocks, climate, soil moisture, and the presence of active leaks. A combination approach—penetrating sealers for structural protection plus surface coatings or breathable sealants for finished surfaces—often yields optimal results. Always follow manufacturer guidelines for surface preparation, cure times, and environmental conditions to maximize performance.