Application Procedures

SEALING ABOVE-GROUND CONCRETE FUEL TANKS

Fuel Tank Construction

This procedure is applicable to above ground fuel tanks. The steel tank is typically insulated with Styrofoam, covered by 30 mil polyethylene sheeting. The outer shell is concrete, typically 6” thick.

The purpose of sealing the concrete is to protect it against deterioration, mainly caused by rainwater and contaminants. The procedure is applicable to both new or older tanks.

Step 1: RadonSeal Deep-Penetrating Sealer

RadonSeal is a silicate-based sealer, which penetrates up to 4” into concrete and reacts with lime and alkali. It seals bare, structurally sound concrete against water intrusion, prevents leaching of lime, and protects concrete against freeze-thaw damage, chemicals, and acid rain. RadonSeal also strengthens the concrete and hardens the surface, which stops concrete dusting and minimizes cracking. It prevents the growth of fungi, mold, and mildew.

The seal is not affected by UV-rays or hot temperatures in direct sun and is permanent for the life of the concrete.

RadonSeal Standard is the best choice for poured concrete in good condition that is less than 10 years old. If older or already deteriorated, use RadonSeal Plus, which contains more minerals for larger pores in the concrete.

RadonSeal is waterborne, nontoxic, nonflammable, and non-hazardous. RadonSeal leaves the surface paintable – the surface “wets.”

Step 2 (Optional): Concrete Armor Plus

This is a more durable and cost-effective alternative to paints or surface sealers.

Concrete Armor Plus is a siloxane-based sealer, which penetrates up to 1” into concrete and forms a water-repellent elastomeric membrane below the surface. It sheds rainwater and if the surface is smooth, it “beads” water. The surface is not paintable.

The sealer protects concrete against freeze-thaw damage, chemicals, and acid rain. It prevents the growth of fungi, mold, and mildew.

Concrete Armor Plus is waterborne, nontoxic, nonflammable, and non-hazardous.

The sealer is not affected by high temperatures in direct sunlight. Since the subsurface membrane is so deep, the seal is highly resistant to UV-rays. Although it may cease beading after several years, it continues to shed water normally for over a decade. Then, it can be re-applied.

Delivery, Storage and Handling

Materials shall be delivered in their original unopened containers and stored in clean, dry areas away from direct sun at 40º to 80º F until ready for use. Protect from freezing during shipping or storage.

Project Conditions

Weather Conditions: Do not apply the sealers in snow, rain, fog, or mist, or when such conditions are expected within 3 days. Ambient air temperatures shall be at least 35º F at application time.

Substrate Conditions: Temperature of the concrete shall be above freezing during the application and for at least 72 hours afterwards.

Do not apply the sealers to hot concrete in direct sunlight. Avoid windy conditions to minimize over-spraying.

Preparation and Surface Cleaning

In case of newly poured concrete, allow at least 28 days to cure.

RadonSeal can be applied only on bare (unpainted) concrete surfaces. The surfaces must be sufficiently clean to allow RadonSeal to penetrate into the concrete.

Water-absorption test: To make sure that the surface is ready for RadonSeal, spray on some water to confirm that the concrete is readily absorbing water.

Remove any paints, surface sealers, or mastics. Special surface preparation is normally not required, but oil slicks must be removed first.

Efflorescence (white mineral deposits) can build up and prevent the absorption of RadonSeal.

Remove any molds, mildew, or algae.

Pressure-wash the concrete (3,000 psi) to remove dirt and residues.

Mask glass and aluminum. Also mask copper, ceramic tiles, and fixtures or just wipe off any over-spray right after the application.

Cover up near-by vegetation, plants and shrubs. Move or cover near-by automobiles and similar objects against over-spray.

Spray Equipment

A low-pressure sprayer like an airless sprayer set at about 40 psi with a lacquer tip and a long hose (100-150 ft.) for mobility Or a battery-powered pesticide sprayer or a back-pack sprayer. A sprayer nozzle with a fan pattern is more controllable than conical pattern.

RadonSeal Application

Safety glasses and breathing mask recommended, particularly when spraying overhead. If splashed in the eyes, wash out with clean water. If swallowed, do not induce vomiting, but drink water for dilution and consult a physician.

Dampen the concrete to reduce surface tension and help RadonSeal penetrate deeper. Spray each section with water and let partially dry until just damp.

Spray the sealer in a thin continuous film. Do not over-apply, do not let the sealer run or puddle. Spread out any puddles with a broom.

Spray on RadonSeal in 2 successive applications about 30–40 minutes apart, while the concrete is still damp. If the 2nd application has absorbed fast (within 5 minutes), spray on a 3rd application 30–40 minutes later.

Dampen and seal a section at a time. Then, move on to the next section.

Coverage Rates

Surface coverage depends on the concrete’s porosity and composition. Concretes with more pores or alkalis consume more sealer.

RadonSeal Standard is used only on newer concrete (less than about 10 years old) and in good shape. RadonSeal Plus is used on older concrete and when the concrete is already deteriorated and very porous.

Spray at a rate of 300-400 sq. ft./gal. for each application. Estimated total consumption in 2 applications 150-200 sq. ft./gal., or 100-125 sq. ft./gal. in 3 applications.

Clean-up after RadonSeal

Clean spraying equipment with clean tap water.

The concrete will appear dry in a couple hours. Any surface residue from over-application would leave a whitish hard film, which cannot be painted or further sealed.

In about 10 to 12 hours after RadonSeal application, pressure-wash the surface using a lower pressure 800-1,000 psi to remove any residue.

Within the first several days, RadonSeal will purge minerals, dirt, and efflorescence from older concrete. This is in a powdery form and can be brushed or power-washed off, or it will just wear off.

If the concrete will be painted, let RadonSeal first cure for at least 10 days.

Concrete Repairs

Repair cracks with readily available epoxy sealants or caulking materials. (RadonSeal is applied first because cracks help the sealer penetrate into the concrete.)

If required, use concrete patching compounds for larger repairs.

Application of Concrete Armor Plus

Let RadonSeal cure for at least 10 days.

The surface must be thoroughly dry. Do not apply if rain is expected within two days.

Spray-on equipment … same as for RadonSeal.

Product safety and precautions … “

Spray the sealer on in a thin, glistening, continuous film (“wet look”), just like RadonSeal.

After 15-20 minutes of spraying, return to the beginning, while still wet, spray on the second application. (If delayed, the first application would cure and would reject the second application.)

Then, move on and seal the next section.

Clean spraying equipment with clean water.

The sealer will be tack-free in several hours.

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