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RadonSeal Deep-Penetrating Concrete Sealers

RadonSeal Penetrating Concrete Sealer

Your Damp Basement Solution

RadonSeal Deep-Penetrating Basement Sealer. The leading penetrating concrete sealer for the preservation and protection of concrete blocks, commercial and residential concrete since its inception in the late 1990s.

RadonSeal is a penetrating, clear, waterborne, reactive-based concrete basement sealer. Used for strengthening and waterproofing poured concrete, heavyweight concrete blocks, limestone, and high-strength cementitious building materials. RadonSeal seals the pores and capillaries of concrete against water and water vapor. It helps reduce basement moisture, humidity, damp proofs concrete, and aids in reducing radon and soil gas transmission. Hardens indoor and outdoor concrete surfaces against dusting, cracking, freeze-thaw, deicing chemicals, and efflorescence.


Give It the Strength It Needs

Unlike concrete waterproofing paint, epoxy, and other chemical sealers marketed towards enhancing the surface appearance and beading water, RadonSeal should be your first choice for protecting the concrete.

Unlike topical sealants, RadonSeal will not trap moisture, because it does not form a membrane on the surface. It will allow your concrete to breathe and dry out. RadonSeal penetrates. This nano-chemical sealer is absorbed deep into concrete, below the surface. It will then chemically react, expand, sealing the pores and capillaries of the concrete, permanently!

Provided it is properly applied to a bare a porous concrete surface, RadonSeal will not alter the appearance of the concrete. It does not leave behind a glossy coating, nor will it change the surface friction of concrete. It is slip-resistant, allowing it to be applied to high-vehicular traffic areas, commercial sidewalks, ramps, parking lots, garages, and warehouse floors.

These important characteristics make RadonSeal considered the best commercial concrete sealer of choice before the application of concrete waterproofing paints, epoxy floor coatings, wet-look sealants, concrete levelers, floating slabs, wood floors, and adhesive. For the homeowner, RadonSeal is a ZERO VOC and solvent-free sealer. Safe to be used in basements and crawlspaces. Use on garage floors, basement floor, basement walls, concrete driveways, pool decks, patios, and walkways.

RadonSeal® Standard

RadonSeal Standard is a water-based, reactive, penetrating concrete basement sealer. Used commercially to seal new concrete. Recommended for poured concrete less than 20-years and outdoor concrete less than 2-years old (can be applied to old concrete). Coverage & Application.

RadonSeal® Plus +

Maximum-strength penetrating sealer. Used for more porous concrete and blocks. Recommended for concrete and cinder blocks, poured concrete older than 20-years, and outdoor concrete older than 2-years (can be applied to new concrete). Coverage & Application

RadonSeal Plus. Peace to the World

Contractor Application >

The Permanent Concrete Sealer

RadonSeal is a clear, water-based, reactive basement sealer that penetrates below a porous concrete surface (up to 4″). It chemically reacts with free lime and alkali (Portland Cement) and continuously cures, hardening as a silicate mineral. Expanding within the matrix of concrete, sealing the pores, capillaries, and fractures that gives concrete its porosity.

The seal it provides within the concrete can never wear away, delaminate, peel, or wear away. It is unable to be pushed out of the concrete, regardless of the amount of negative-side water pressure. The seal becomes integral to the concrete itself. No reapplication is ever required. It is like injecting more cement into your concrete.

Waterproofs Concrete Below The Surface

Applying RadonSeal helps to protect below-grade concrete, slab-on-grade construction, cellars, basement walls, crawlspaces, and subterranean commercial areas. Use it to combat groundwater seepage, moisture, dampness, water vapor, damp concrete blocks, humidity, and sweating garage floors.

Seal interior/exterior foundation walls and basement floors before applying concrete paint, epoxy, and damp-proofing membranes (tar, asphalt, rubberized coatings). Outdoor coatings do not last forever, and as they begin to break down, wear, and crack, RadonSeal will be that last line of defense against the water.

Adding further waterproofing protection to concrete by blocking capillary water seepage and the infiltration of water vapor helps alleviate (if not stop) the leaching of efflorescence and salt deposits. RadonSeal will help protect and extend the life of concrete waterproofing paints or epoxy moisture coatings which can be pushed off the surface by efflorescence buildup underneath.

Strengthens Concrete Surfaces

In addition to the waterproofing capabilities, RadonSeal will strengthen and densify concrete. Strengthening concrete helps to preserve the integrity of the substrate against concrete dusting, cracking, concrete spalls, surface crazing, aggregate pop-outs, and minor defects due to surface traffic.

As a concrete densifier, RadonSeal protects outdoor concrete against freeze-thaw, deicing chemicals, vehicular traffic, rebar corrosion, acid rain, lawn irrigation systems, and unsightly efflorescence.

Helps Reduce Radon and Soil Gases

Radon gas can sneak into homes and basements through openings in the basement and crawlspaces, cracks, gaps, open sump pits, hollow-core concrete block walls, and through the pores of the concrete. Radon gas kills over 21,000 people in the United States every year. After cigarette smoking, radon is the second leading cause of lung cancer deaths in the U.S.

“Radon in homes causes more deaths than fires, drownings, and airplane crashes combined.” –

The health risks are proportional to the radon levels in your home. There is no “safe” radon level. Seventy percent of radon attributed deaths are caused by homes with radon levels below 4 pC/L, which is the US EPA’s “Action Level”. It is advised to reduce radon levels to a practical minimum!

Applying RadonSeal to indoor concrete provides an effective mitigation method that can aid and/or reduce radon levels in your home. In comparison to fan-based mitigation systems, sealing openings and applying a radon sealer to concrete can sometimes save on the initial cost and operating costs year after year.

The RadonSeal Advantage for Concrete

Choosing to ignore the use of a concrete sealer would be similar to not sealing and protecting wood surfaces. Using RadonSeal on indoor and outdoor concrete provides several important benefits to concrete, home, basement, and the homeowner:

  • Concrete Waterproofing – Can greatly reduce capillary water seepage, water vapor, and concrete moisture.
  • Efflorescence – RadonSeal reacts with the alkalis inside the concrete and can stop or minimize efflorescence and salt deposits.
  • Eco-Friendly – ZERO VOCs, no solvents, no noxious odors or fumes. Safe for indoor use!
  • User-Friendly – Water-based (not solvent-based). Easily applied using a low-pressure, hand-pump “garden or bug” sprayer.
  • Vapor Transmission – Restricts water vapor inflow before the installation of moisture-sensitive flooring
  • Radon Mitigation – Aids in reducing radon levels by restricting the infiltration of soil gases through concrete capillaries and pores.
  • Breathable Sealer – Does not trap water vapor. Allows concrete to breathe and dry.
  • Mold Remediation – Aids in the prevention of mold and mildew growth.
  • Musty Odors – Helps to alleviate musty basement odors by reducing moisture, humidity.
  • Reduces Cracking – Protects against the rusting and expansion of rebar which can cause cracking.
  • Concrete Hardener – Strengthens surfaces flint hard. Protects against freeze-thaw and road salts.
  • Neutralizes Alkalis – Reduces high pH which helps improve the success of water-based stains and concrete paints. Ideal for reducing pH in fish and koi ponds, dog kennels, and animal stables
  • Deep-Cleans – Purges contaminants, old efflorescence, minor oil and grease spills, and animal urine to the surface.

Concrete Surface Uses

Because RadonSeal works by reacting with Portland Cement, it is most effective when used on high-quality concrete (+3″ thick) such as:

  • Poured Concrete Sealer – Below-grade foundation walls, wet basement walls, and basement floors. Garage slabs. Slab-on-grade constructions. Crawlspace slabs. Factory and warehouse floors. Commercial concrete. Driveways, sidewalks, pool decks, patios, carports, concrete curbs, parking lots, seawalls, storage tanks, cooling towers, concrete bridges, concrete columns, building facades.
  • Concrete Block Sealer – Basement walls, building facades, and retaining walls. See Cinder Block Sealer.
  • Mortar Sealer – Helps to solidify mortar between concrete blocks and porous mortar in older stone foundation walls.
  • Limestone Sealer – Old basements walls constructed from limestone and concrete. Limestone building facades and columns. Interior or exterior.


Stamped, colored or stained concrete, polished concrete floors, modified hydraulic cement, fiber-reinforced concrete, outdoor split face or lightweight blocks, bricks, pavers.

Basement Sealer for Foundation Walls and Floors

RadonSeal Concrete Sealer is most commonly applied to restrict moisture, capillary water seepage, water vapor, and efflorescence on indoor, below-grade foundation walls, basement floors, slab-on-grade construction, foundation concrete blocks walls, retaining walls, and sweating garage slabs. In addition to the waterproofing capabilities, RadonSeal is used to strengthen and densify concrete, indoor and outdoors. Helping to preserve and protect against concrete dusting, cracking, efflorescence and spalls.

RadonSeal Standard and RadonSeal Plus are the strongest formulated silicate-based concrete sealers because they penetrate deeper, carry more active minerals into the concrete, and seal tighter than other concrete basement sealers. Penetration does not rely upon gravity to penetrate, it penetrates by capillary action allowing for use on basement walls and concrete ceilings.

Because excavating foundation walls is expensive and often not always feasible, RadonSeal is commonly applied to the inside of the basement and foundation walls. However, if there is an opportunity to apply it to both sides of the concrete walls, it has the added advantage of preserving the exterior surface of the concrete and extending the life of any waterproofing coating by protecting it against saponification caused by alkalis from the concrete.

Use RadonSeal Before Painting or Hardwood Flooring

When applied to a sufficiently porous concrete surface, RadonSeal leaves the surface paintable (does not bead water). Sealing damp concrete floors and damp basement walls with high-moisture rates is recommended before applying floor coatings, paints, adhesives, mastic, gloss finish epoxy or urethane coatings, wet-look sealers, concrete overlays, surface levelers, or moisture-sensitive flooring (wood floors).

RadonSeal seals concrete floors to greatly reduce the wicking of water, water vapor through the pores and capillaries of the concrete. Deep-sealing a concrete slab helps block efflorescence which protects epoxy coatings and paints from cracking and peeling. Applying RadonSeal helps protect clear coatings from delamination and blushing and hardwood floors from trapping moisture, leading to buckling and mold growth.

For more info on how RadonSeal works, efflorescence, the “alkali attack,” how to protect concrete, paints, and flooring against deterioration, visit RadonSeal – Your First Choice for Sealing Concrete.

Lifetime Guarantee

Waterproofing Guarantee – Please review the RadonSeal Waterproofing Guarantee in detail.

Radon Guarantee – Please review the RadonSeal Radon Reduction Guarantee in detail.

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