A masonry sealer is a penetrating or surface coating applied to brick, block, or stone surfaces, reducing water absorption and protecting against efflorescence, staining, and freeze-thaw damage without necessarily providing the full protection a dedicated waterproofing system would offer.
These sealers work by either penetrating into the masonry’s pores to repel water from within, or forming a thin protective film on the surface, depending on the specific product chosen.
Because masonry is naturally porous, sealing it periodically is a common maintenance practice for both above-grade and below-grade masonry surfaces facing regular moisture exposure.
What Does a Masonry Sealer Involve?
- Penetrating or film-forming sealer products
- Application to clean, dry masonry surfaces
- Reapplication on a periodic maintenance schedule
- Protection against absorption, efflorescence, and freeze damage
Why Are Masonry Sealers Important?
Regularly sealing exposed masonry, whether a basement wall, a retaining wall, or exterior brick, meaningfully reduces water absorption and the associated risks of efflorescence, staining, and freeze-thaw cracking that untreated masonry is prone to over time. This relatively low-cost maintenance step can meaningfully extend the lifespan of masonry surfaces exposed to regular moisture.
It’s important to recognize that a masonry sealer reduces water absorption rather than eliminating water penetration entirely, which is why it’s generally not considered an adequate substitute for actual waterproofing on a below-grade wall facing real hydrostatic pressure. Reapplying on the manufacturer’s recommended schedule keeps this protection consistent year after year. This routine, low-cost maintenance step is easy to overlook but genuinely worthwhile over time. This modest task delivers outsized long-term protection.
Masonry Sealer vs. Concrete Sealer
Masonry sealer is formulated for brick, block, and stone surfaces. Concrete sealer is formulated specifically for poured concrete, and while the two product categories share some similarities, using the wrong type for a given substrate can result in poor adhesion or performance.