Cementitious waterproofing is a waterproofing coating made from a cement-based mixture combined with waterproofing additives, applied to concrete or masonry surfaces to create a rigid, durable water-resistant layer that bonds directly and permanently to the substrate.
Because it’s cement-based, this type of coating bonds exceptionally well to concrete, forming a strong chemical connection rather than simply sitting on top of the surface the way some other coatings do.
Its rigidity is both a strength and a limitation, offering excellent durability on stable substrates but less tolerance for movement compared to more flexible elastomeric alternatives.
What Does Cementitious Waterproofing Involve?
- A cement-based mixture with waterproofing additives
- Application by trowel or brush in multiple coats
- Strong chemical bonding to concrete substrates
- Curing into a rigid, durable protective layer
Why Is Cementitious Waterproofing Important?
Its strong bond and durability make cementitious waterproofing a popular choice for interior applications, like waterproofing a basement wall from the inside, where its rigidity isn’t a significant drawback since interior walls typically experience less movement than exterior surfaces exposed to backfill and soil pressure. This durability also makes it a common choice for below-grade structures like swimming pools and water tanks, where constant water contact demands a genuinely long-lasting seal.
Because this coating doesn’t flex the way an elastomeric product does, it’s generally less suitable for surfaces with active or expected cracking, where a more flexible waterproofing approach would better accommodate ongoing minor movement. Matching the coating type to expected movement conditions is a decision worth discussing with an experienced contractor.
Cementitious Waterproofing vs. Elastomeric Coating
Cementitious waterproofing bonds rigidly to concrete, offering strong durability but limited flexibility. Elastomeric coating trades some of that rigidity for the ability to stretch across minor cracks, making the choice between them depend largely on how much movement the substrate is expected to experience.