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RadonSeal Efflorescence Cleaner

Efflorescence Cleaner by RadonSeal

Easily Remove Efflorescence from Concrete, Brick, and Masonry

Powdery, hair-like, growth on your bricks or blocks? Chalky mineral deposits on your concrete slab or foundation walls? If yes, you have efflorescence, and you are not alone. The good news is that RadonSeal Efflorescence Cleaner has changed the way contractors and homeowners deal with efflorescence on concrete surfaces, bricks, pavers, and other masonry. Say goodbye to harsh acids and dangerous chemical cleaners and say hello to a safer, more reliable, effective efflorescence cleaner.

Efflorescence Cleaner


What Makes RadonSeal Efflorescence Cleaner So Special?

Cleaning efflorescence used to require flushing concrete with muriatic, hydrochloric, or buffered phosphoric acids. These acids are extremely hazardous to your health and can damage surfaces. Breathing acid fumes will make you choke, and skin or eye contact can cause severe burns. Using these types of products outdoors is a problem enough, while working with them indoors is next to impossible.


RadonSeal Efflorescence Cleaner replaces the “old-school” acid cleaners. So put away your respirator and plastic suit. Choose the safer way to remove surface efflorescence, “sub-efflorescence” (efflorescence that exists below the surface of concrete), lime and mortar stains, as well as rust stains. Our efflorescence cleaner contains no phosphoric acid, muriatic or hydrochloric acid, bleach, abrasives, or petroleum distillates.

  • SAFER – Non-corrosive to skin. Safe for indoor use. Acid-free formula.
  • FORMULATED STRONG – 70% more effective than glycolic acids, 50% more effective than phosphoric acid.
  • EASY APPLICATION – Ready to use. Simply spray or brush.
  • NO NEUTRALIZATION – Water-soluble. Skip the dreaded neutralization step.

RadonSeal Efflorescence Cleaner uses an organic salt that acts like acid but is only considered a mild skin irritant and not corrosive. Suitable for industrial, commercial, and residential use. Use to remove deposits from basement floors, foundation walls, garage floors, retaining walls, brick, stucco, mortar joints, cinder blocks, or any other surface that requires cleaning. RadonSeal Efflorescence Cleaner is the ONLY industrial-strength efflorescence cleaner made safe for use indoors and formulated STRONG to remove even the most stubborn of stains!

What is Efflorescence?

Efflorescence is a very common and frustrating problem. It appears when soluble alkali salts are carried to the surface of concrete and masonry by water. Once the water evaporates, the salts are left behind leaving a whiteish, mineral stain on the surface. Wire brush it off and more efflorescence eventually appears again. Try to cover it with paint and you will only discover the efflorescence building up underneath, causing the paint to peel and lose its adhesion to the surface. Efflorescence is one of the main causes as to why paints fail!

Think applying a topical sealer will solve the problem? Think again! Clear membrane sealers will trap efflorescence, causing the appearance underneath to discolor. This is often described as blushing or hazing under non-breathable, clear epoxy, urethane, and acrylic sealers. In severe cases, efflorescence can cause sealer delamination. In fact, applying the “wrong type” of sealer may make your efflorescence problem worse!

Can efflorescence be stopped?

How To Prevent Efflorescence from Returning

Removing existing efflorescence is the first step, but it is not the last. Water will continue to seep through the capillaries and evaporate, leaving behind fresh efflorescence. Do not paint or apply a topical sealant to the surface! Doing this will trap water vapor and increase the moisture level inside the concrete. This will activate more efflorescence, which will start pushing off the paint or surface sealer.

Deep-Seal the Substrate – Waterproof the concrete or mortar deep inside to prevent water migration. How simple! No more efflorescence can be carried to the surface. Follow these simple steps:

STEP 1 – Remove the efflorescence with RadonSeal Efflorescence Cleaner.

STEP 2 – Deep-seal the concrete, concrete blocks, or cinder blocks with RadonSeal Penetrating Concrete Sealer. As RadonSeal reacts and expands, it will purge dirt and efflorescence from deep inside the pores to the surface for up to five days. It may look like a fine “whitish fuzz”. Brush off loose efflorescence and clean the concrete again with the Efflorescence Cleaner. In the case of brick walls, use LastiSeal Brick & Concrete Sealer. It will deep-seal the mortar against the movement of water (without purging the pores).

Choose the Best Sealer for Your Project

When It’s Not Efflorescence

IMPORTANT – RadonSeal Efflorescence Cleaner is extremely effective for the removal of efflorescence, dissolved salts, lime, and alkalis. However, lime (calcium hydroxide) in the efflorescence gradually reacts with carbon dioxide in the air (carbonation), forming calcium carbonate (CaCO3). The carbonate is often difficult to remove and may require multiple applications of the Efflorescence Cleaner or mechanical abrasion.

  • Rocky Build-Up – A thick rocky build-up (calcium carbonate) is created by long-term efflorescence and carbonation. It has to be removed with a chisel, grinder, or blasting unit.
  • Streaking – When mortar, plaster, or stucco with a very high lime content is exposed to water, rain, or sprinklers, the lime gets washed out and runs down on the surface. The dissolved lime reacts very quickly to become carbonate. White streaks on brick walls are typical. This may be removed using our Efflorescence Cleaner, but mechanical means are often necessary (wire wheels, soda blasting, sanding, or grinding).

Surface Preparation | Coverage

COVERAGE – 200 sq. ft./gal (estimated)

SURFACE PREP– Remove paints, previous sealers, coatings, or adhesive. Clean oil and ground-in dirt. Oil deposits can be cleaned with a dishwashing liquid (like Dawn) or a commercial degreaser like our Novion Universal Concrete Cleaner.

  • CLEAN EXCESSIVE EFFLORESCENCE – Use a wire brush to easily remove loose efflorescence. If there is a hard build-up, chisel or grind it off.
  • DRY SURFACE – The concrete, brick, or masonry surface should be dry.
  • AVOID OVER-SPRAY – Mask objects like fixtures, windows, soft metals, and plants to protect them against over-spray.


RadonSeal Efflorescence Cleaner provides a user and environment-friendly way to clean concrete, bricks, and masonry. It works quickly, has no odor. Use outdoor or indoors.

STEP 1 – Apply liberally to affected areas using a sprayer, brush, or roller. Allow the cleaner to react and break down mineral deposits.

STEP 2 – While still wet, re-spray and scrub heavy deposits. Scrub with a wire brush.

STEP 3 – Rinse treated surfaces. Add water to treated surfaces to dilute and remove the cleaner.

Common Uses

RadonSeal Efflorescence Cleaner can be safely used on poured concrete, concrete blocks, bricks, stucco, pavers, and artificial stones. The cleaner chemically breaks down and removes efflorescence, lime deposits, metal salt stains, and rust deposits. Typical concrete, brick, and masonry brick cleaning projects:

  • BRICK and MORTAR JOINTS – Cleaning efflorescence off exterior brick walls, chimneys. Fireplaces, facades.
  • PAVERS – Cleaning pavers on pool deck or patios.
  • BASEMENT FOUNDATION WALLS – Removing efflorescence off basement walls and floors, or foundation slabs.
  • HISTORICAL RESTORATION – Commonly used for renovation projects of older buildings, homes, or structures.
  • LAITANCE – Cleans laitance on new concrete (must be at least 10 days old and thoroughly dry.)
  • MONUMENTS and STATUES – Stone monuments, concrete statues.

Technical Data Sheets