Koster LEVELSTRONG Skim Coat - 10 lb Bag - SL 282 022

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Skimcoat patch underlayment.


KOSTER LevelStrong SC is a high quality, fast curing skimcoat underlayment that provides a smooth, level surface ready to receive flooring systems. It may be applied over KOSTER VAP I 2000 coatings and concrete. KOSTER LevelStrong SC accepts all major floor coverings and is compatible with most adhesives. If the material is installed onto smooth, non-absorbent substrates such as KOSTER VAP I 2000 coatings, the substrate must be primed with KOSTER VAP I 06 Primer.

Technical Data

Property  Data
Compressive Strength 3500 psi (ASTM C109)
Flexural Strength 1500 psi (ASTM C348)


Fields of Application

KOSTER LevelStrong SC is designed to provide a smooth and level surface of plain concrete surfaces as well as surfaces coated with KOSTER VAP I 2000 moisture control coatings. It is intended for interior use.


Concrete substrates to receive KOSTER LevelStrong SC must be sound, clean and absorptive, free of curing agents, oil, grease, paint, loose particles or any other contaminant that may weaken the bond. The pull off strength of the substrate must be at least 200 psi. Do not acid etch substrates. Do not clean substrate with chemicals. Do not apply over adhesive residue. Do not bridge expansion joints with KOSTER LevelStrong SC. Expansion joints must be installed accordance with local building codes.


Plain concrete without KOSTER VAP I 2000 coating
Concrete substrates are prepared by shot blasting, or grinding in order to achieve an absorbent, open pored substrate. No primer is required over concrete.

Concrete coated with KOSTER VAP I 2000 coating 
The properly installed and fully cured KOSTER VAP I 2000 coating is primed using KOSTER VAP I 06 Primer (coverage: 500-600 sq ft/gal). For further information, refer to the data sheet of the KOSTER VAP I 06 Primer.

Add 1.7-1.8 (1.6-1.7 L) quarts of clean, cool, potable water into a clean mixing vessel. Do not overwater. Add the 10 lb bag of KOSTER SC while mixing with an electrical mixer (650 rpm). After all material has been added, mix for 2-3 minutes. The resulting consistency should be lump free. Material can also be mixed at a ratio of 1 part water to 2 parts KOSTER LevelStrong SC, by volume.

Apply the mixed material by trowel to the desired thickness. KOSTER LevelStrong SC can be installed between 1/8 and 1/2-in. The material will set within 10-15 minutes. After initial set, remove all overlap marks, seams, and inconsistencies by smoothing with a steel trowel. Material can be walked on after 15-20 minutes, depending on thickness and ambient conditions. Finish flooring systems can be applied within 30 minutes depending on thickness, ambient conditions, and flooring system.

Approx. 35 sq ft/10 lb bag at 1/8-in

Use water to clean all tools immediately after use.

10 lb bag ( SL 282 022)

Store in a cool, dry place.

Consult Safety Data Sheet. Contains Portland cement and silica sand;
avoid contact with eyes or prolonged contact with skin. Do not take
internally. Eliminate exposure and avoid breathing dust; contains free
silica. Wear personal protective equipment including gloves and safety
eyewear. In case of eye contact, flush immediately with water and
consult a physician. In case of skin contact, wash immediately with
soap and water.

Limited Warranty
KOSTER warrants that its product shall be in accordance with the specifications published in the current revision of the products data sheet. KOSTER covenants that in the event any of its products fail to meet their published specifications, KOSTER shall replace those products proved to be defective. KOSTER shall not be responsible for any incidental or consequential damages due to the breach of its warranties. Notwithstanding the foregoing, KOSTER’s sole liability hereunder shall not exceed the cost of the defective product originally purchased. EXCEPT AS SET FORTH ABOVE, KOSTER MAKES NO OTHER WARRANTIES EXPRESS OR IMPLIED AND MAKES NO WARRANTY AS TO THE MERCHANTABILITY OR FITNESS OF THE PRODUCT FOR A PARTICULAR PURPOSE. THERE ARE NO WARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION ON THE FACE HEREOF. The user must determine if the product is suited for the intended use and the user must bear the risks and liabilities associated with it.