What is the best way to seal cinder block walls?

Author: Flo Stokes  |  Last update: Thursday, April 16, 2026

A silane/siloxane-based sealer is a far better option for sealing cinderblock its blend of large and small particles, designed specifically for porous material, penetrate the surface and chemically react below the substrate to form a water-repellent barrier.

What is the best sealer for cinder block?

Applying RadonSeal Plus and Ion-Bond Armor is the best concrete block sealer for use on cinder blocks foundation walls. The combination of the two concrete sealers has proven to be foolproof for many frustrated homeowners dealing with damp basements.

Do cinder block walls need to be sealed?

Concrete block walls provide a great surface for stucco to adhere to without the need for sealants. In fact, sealing may actually make it more likely that water will get trapped between the block wall and the stucco coating, making long term adherence almost impossible.

Is it better to spray or roll cinder block walls?

Yes. Best and most efficient application is to spray and backroll all coats. The same results can be achieved just brushing and rolling. The airless puts the material from the bucket to the wall faster. The roller evens it out and fills voids.

How do you stop water from seeping through cinder blocks?

First repair any cracks in the foundation, then apply a liberal coat of drylok. You want to fill all the pores in the block. This will solve most water problems. On the outside you may be able to alleviate some of the problem with gutters and correctly positioned downspouts.

How to Waterproof Concrete Block, Best Waterproofing for Concrete Block

Will Drylok stop water?

DRYLOK® Original Masonry Waterproofer will withstand 10 pounds of hydrostatic pressure (PSI), equivalent to a wall of water 22 feet high, and is GUARANTEED TO STOP WATER.

How to stop moisture from coming through concrete walls?

Use Concrete Sealers, Repellents and Coatings

A penetrating sealer can help keep moisture from compromising concrete. It essentially creates a protective layer, filling the gaps around flashings and between adjoining surfaces. These gaps would otherwise allow passages for water and moisture to enter the unit.

Is it better to roll or spray concrete sealer?

The answer depends on the surface's square footage. For large surfaces such as commercial floors, a sprayer is faster and way more efficient. Finally, for small surfaces, such as garages or any other exterior surface, a paint roller or any other type of roller will do the trick. Rolling is a less expensive process.

Why backroll after spraying?

Back-rolling right after spraying works the coating into the surface more efficiently than spraying alone, promoting better adhesion between the coating and the substrate (which is most often drywall when working on residential interiors).

What is the best cover for a cinder block wall?

Vinyl siding is an enduring and low-maintenance choice for covering external cinder block walls. It is a sensible option for improving the external appearance of your home because it provides good resistance to fading, weathering, and moisture damage.

What is the best way to seal a block?

A silane/siloxane-based sealer is a far better option for sealing concrete blocks its blend of large and small particles, designed specifically for porous material, penetrate the surface and chemically react below the substrate to form a water-repellent barrier.

How much does it cost to seal a cinder block wall?

Sealing concrete sealing or “seal coating” costs between $1.20 – $1.75 per square foot. Factors that determine cost include project fees, quality of concrete, stamped vs regular, or if you opt to do it yourself.

How long do cinder block walls last?

A cinder block retaining wall can last a very long time, typically between 50 to 100 years, depending on the quality of materials used and the conditions it's exposed to. Proper construction and maintenance are crucial for longevity.

What is the most durable concrete sealer?

Epoxy concrete sealers are the most durable, making them good for sealing garage floors and high-traffic retail environments. Softer acrylic sealers, which require a sacrificial floor wax, are more affordable and popular for residential concrete floors, including basements.

How do you seal and paint cinder block walls?

Use concrete and masonry bonding primer. Do not use wood or drywall primer or self-priming paint. After priming, you can use ordinary acrylic-latex paint tinted to the color of your choice. Use interior paint on interior cinder blocks and exterior-grade paint on outdoor surfaces.

Do cinder blocks deteriorate?

The life span of concrete masonry units can vary depending on several factors, but in many cases, CMUs can last up to 100 years. Unlike materials like wood and some metals, concrete doesn't deteriorate over time.

Is rolling better than spraying?

Ultimately, the decision between using a sprayer vs rolling paint for your next project depends on your preferences and goals for the job. If speed and efficiency are your top priorities then spraying may be the better option; however, if you're looking for a more precise finish then rolling is the way to go.

Is it better to spray or roll drywall primer?

Conclusion. Typically, back rolling after spraying on walls and ceilings is ideal especially for your primer. It will help in promoting better adhesion of the primer and reduce issues of raised filaments with drywall.

What is the best applicator for concrete sealer?

LPHV (low-pressure, high-volume) or airless sprayers: These sprayers are usually the best way to apply any sealer. They permit very controlled application rates, allowing large areas to be sealed in the shortest time.

Is quikrete concrete sealer good?

Overall, the product is well-received for its effectiveness, though users recommend careful application techniques to achieve the best results.

What is the best sprayer to use for concrete sealer?

Low-pressure high-velocity (LPHV) driveway sealer sprayers are also called “airless” sprayers. They are most suitable for applying both water- and solvent-based film-forming sealers, but may not be well suited for certain penetrating sealers.

How to prevent mold on cinder block walls?

Lower the relative humidity.

Concrete is a poor insulator and therefore can become quite cool during the winter months. In a poorly ventilated basement, this can cause airborne moisture to condense on the surface and cause mold growth. There are three ways to reduce the RH in the area.

Can you put a vapor barrier over concrete?

Absolutely! One of the biggest pieces of evidence for this is the use of vapor retarders, which are intended “to limit water vapor from entering concrete slabs in contact with the ground” (ACI 302.2). Installing vapor retarders under a slab has become standard practice.

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