Armstrong Flooring S-463 Level Strong™ Self Leveling Underlayment DATA SHEET



Honor all designed movement joints in the concrete subfloor up through S-463 Level Strong™ and finished flooring. Designed non-movement concrete subfloor joints such as crack-control joints should be thoroughly cleaned and filled with an appropriate cement-based patch such as S-466 Patch Strong™. Random cracking in the concrete subfloor should be evaluated to determine the cause. If it is determined the cracking is caused by structural movement the cracks should be remediated.
Armstrong Flooring cannot be responsible for concrete joint and/or crack show through related to structural movement.

  • Intended for interior use only. Do not use in areas of constant water exposure (such as swimming pools) as this may jeopardize the performance of the underlayment and the floor covering.
  • This product is not a vapor barrier.  Where concrete moisture exceeds the maximum allowed, prepare the surface first by using Armstrong S-462 Seal Strong™ Two Part Moisture Mitigation System.  
  • Always install an adequate number of properly located test areas, to include the finish flooring, to determine the suitability of the product for its intended use.
  • Carefully read and follow all cautions and warnings on product label.
  • Never mix with cement or additives other than Armstrong Flooring approved products.
  • Observe the basic rules of concrete work.
  • Do not install below 50°F (10°C) ambient and surface temperature.
  • Install quickly if substrate is warm.
  • Store indoors in a cool, dry, location. Out of direct sunlight.


S-463 Level Strong MSDS

Product Information

TypeCement Based Self-Leveling Compound mixed with plain water
TrowelSmoothing trowel
Thickness1/16″ up to 1-1/2″ thick on porous substrates.  Limit to 1/2″ thick on non-porous substrates. 
Coverage52 – 56 sq. ft. at 1/8” thick per bag
Mix RatioFor thin applications of less than 1/4″:  Add 50 lb. (22.7 kg) powder to 6 quarts (5.68 liters) of cold clean water.  For applications 1/4″ thick and greater, use 5.75 quarts (5.44 liters)
Flow Time10 minutes at 70°F (21°C)
Shelf Life1 year if unopened, stored in cool, dry conditions
VOC Content0 g/L; Calculated, SCAQMD 1113
Freeze/Thaw StableN/A
Clean UpClean tools in water immediately. Do not flush material down drains.
AdvantagesHigh compressive strength of 5,300 psi (after 28 days)
Flexural Strength (ASTM C348): 1,000 psi (70kg/cm2) at 28 days
Unaffected by concrete moisture of up to 99% RH
Ready for foot traffic in 2-3 hours
Longer working time and faster drying time
Size50-pound bag
Item No.00463500
Dimensions21.5″L x 11″W x 5″H
Carton Weight50.3 lbs
Bags per Pallet48 bags


When used with recommended Armstrong Flooring products, the Strong System™ adds 10 years to the Armstrong Commercial Flooring Limited Warranty.

Product Features

For use with the following commercial and residential applications:

  • Overall leveling of concrete subfloors on any grade level
  • Rapid drying cement screed systems
  • Ceramic & quarry tile, epoxy coating systems, and terrazzo substrates
  • Non-water soluble adhesive residues on concrete
  • Armstrong Flooring S-462 Seal Strong™

Substrate Preparation

Concrete Surface Preparation: All concrete surfaces must be solid, structurally sound, and clean and free of dirt, oil, grease, asphalt, plaster, latex and gypsum compounds, petroleum- or wax-based emulsion curing compounds, dissipating compounds, polish, wax, sealers and other foreign matter as described in ASTM F-2873 “Standard Practice for the Installation of Self-Leveling Underlayment and the Preparation of Surface to Receive Resilient Flooring”.  If such contaminants are present, mechanically remove by shot blasting or similar. Do not use acid-etching, solvents, or sweeping compounds to clean substrate. Always refer to the Armstrong Flooring Guaranteed Installation System Manual, F-5061.

Completely remove existing water-soluble adhesives and underlying patching materials by mechanical means.  Do not use solvents or adhesive removers.  Non-water-soluble adhesives must be wet-scraped down to a thin well-bonded residue. Some previously manufactured asphaltic “cutback” adhesives contain asbestos. For removal instructions, refer to the Resilient Floor Covering Institute’s publication Recommended Work Practices for Removal of Resilient Floor Coverings.

Concrete floors must be free of excess moisture and/or alkali. In cases of excessive moisture, the use of Armstrong Flooring S-462 Seal Strong™ may be applied. If covering Armstrong Flooring S-462 Seal Strong with Armstrong Flooring S-463 Level Strong™ or Armstrong Flooring S-466 Patch Strong™, priming with Armstrong Flooring S-465 NP Prime Strong™ is necessary.

Armstrong S-463® Level Strong™ also can be applied over clean, sound and solidly bonded non-porous surfaces including terrazzo, burnished concrete, epoxy coating systems, and ceramic, quarry and porcelain tiles. The substrate must be clean, including the complete removal of existing waxes and sealers, dust, dirt, debris and any other contaminant that may act as a bond breaker. Where necessary, substrate preparation must be by mechanical means, such as shot blasting.

Application Instructions:

Porous substrates must be primed in accordance with Armstrong Flooring S-464 Prime Strong™ Porous data sheet instructions.  
Non-porous substrates must be primed in accordance with Armstrong Flooring S-465 NP Prime Strong™ data sheet instructions.

Mixing: Armstrong S-463 Level Strong may be applied from 1/16” up to 1-1/2” thick on porous substrates.  Limit to ½” thick on non-porous substrates.

For thin applications less than ¼” thick: Using a clean mixing drum, add 50 lb. (22.7 kg) unit to 6 quarts (5.68 L) of clean, cold water to form a homogeneous mixture.

For application thicknesses of ¼” up to 1-1/2” thick: Use 5.75 quarts (5.44 L) of clean, cold water.

Mixing Instructions: Mix thoroughly for approx.  2 – 3 minutes using a heavy-duty drill (min.  650 rpm) and mixing paddle to obtain a lump-free mix.  The appearance of a yellowish foam while mixing is a sign of overwatering. Do not overwater.

Application: Armstrong S-463 Level Strong has a flow time of 10 minutes at 70°F (21°C).  Pour the mix and spread using a smoothing trowel. Even surfaces are easily achieved using a pin leveler. In higher thicknesses a spike roller may be used. Wear cleated athletic shoes (non-metallic) to reduce displacement of material. Contact to vertical structures should be avoided by putting in an edge strip. 

Ready for Armstrong Flooring:  In 16 hours when installed up to 3/8″ thick.  For thicknesses greater than 3/8″ wait 24 hours before conducting a mat test for dryness, per ASTM D4263.

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Updated on September 14, 2022