CEM-KOTE FLEX ST - Flexible Cementitious Waterproofing

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No. 704

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CEM-KOTE® FLEX ST
Flexible Cementitious Waterproofing

ANSI/NSF Standard 61 Drinking Water System Components

DESCRIPTION
CEM-KOTE FLEX ST is a highly flexible, fiber-reinforced, breathable, cementitious slurry, consisting of dry Component A and liquid Component B.

USES
CEM-KOTE FLEX ST is designed for positive and negative waterproofing of concrete structures in new construction and restoration. It is suitable for water and wastewater tanks, secondary containment structures, tunnels, concrete slabs, balconies and patios with light to medium traffic. In new construction, where superior flexibility is required (waste water treatment facilities), CEM-KOTE FLEX ST may be reinforced with REINFORCING FABRIC HD throughout. In restoration, REINFORCING FABRIC NW is used just over the cracks to provide bridging.

PACKAGING
CEM-KOTE FLEX ST premix kit consists of dry component A packaged in 35.3 lb. (16 kg) bags and liquid component B, packaged in 1.3 gal. (4.8 L) plastic jugs.

COLOR
Industrial Grey, Light Grey, White.

YIELD
CEM-KOTE FLEX ST yields 0.37 ft.³ (10.5 L) and covers approximately 70.6 ft.² @ 63 mils (6.56 m² @ 1.6 mm) thickness per kit, applied in two (2) coats.

The actual coverage will depend on surface roughness and the thickness applied. The applicator must carry out a sample application to determine the actual coverage for the given substrate and application thickness.

SHELF LIFE
CEM-KOTE FLEX ST, when stored on pallets in a dry, cool area, free from moisture and direct sunlight, has a shelf life of 12 months. The liquid component B must not freeze.

APPLICATION
Follow manufacturer’s most recent application procedures and details to assure quality installation. The applicator must, prior to bid, confirm detailing, use of REINFORCING FABRIC, correct surface preparation, and application procedures with manufacturer’s Technical Services. The applicator must also arrange a pre-installation meeting the manufacturer’s technical representative, general contractor and site engineer to review installation procedure. The project specification supersedes the Gemite guide specification. Current guide specification and application instructions contain additional information specific to each application and must be followed.

Surface Preparation … Remove all deteriorated and loose concrete, form release agents, oil, grease, laitance, dust, dirt and efflorescence by dry or wet sandblast, shot blast, or high-pressure water (minimum 34.5 MPa [5,000 psi] or 24.1 MPa [3,500 psi] with sand brought to the nozzle). Repair deeper areas using MEADOW-CRETE® GPS from W. R. MEADOWS. Remove all loose rust from any exposed reinforcing steel. The proper surface preparation is essential for a successful waterproofing and concrete repair using CEM-KOTE FLEX ST.

Crack Treatment … All cracks must be treated using CEM-KOTE FLEX ST and REINFORCING FABRIC NW. Pre-fill any open cracks larger than 2 mm (80 mils) with CEM-KOTE FLEX ST. Apply a thin coat of CEM-KOTE FLEX ST 6-10” (15-25 cm) wide over the crack. Embed a strip of REINFORCING FABRIC NW into the wet CEM-KOTE FLEX ST, let dry sufficiently, and apply a second coat to fully cover the REINFORCING FABRIC NW.

Mixing … Thoroughly mix the liquid Component B prior to its use. Use paddle or helix mortar mixer or heavy-duty drill (400-600 rpm) with a mixing paddle. Pour approximately 80% of component B into a clean mixer and gradually add the dry component A, while mixing, until a smooth and lump free mix is obtained. Lumps will form if the dry material is added suddenly into the liquid. Add the remaining liquid, while mixing, to achieve the consistency required for a given application. A small amount of water can be added, if required, at higher ambient temperatures.

Application … Trowel or brush apply CEM-KOTE FLEX ST to a minimum thickness of 1.6 mm (63 mils) in two (2) coats to a saturated surface dry (SSD) concrete. CEM-KOTE FLEX ST can also be spray applied using a hopper gun or displacement (moyno or carrousel) pump, with a suitable plastering spray nozzle. When using spraying, brush each coat to eliminate all pinholes. The second coat must be applied into a wet first coat, usually within 10-15 minutes, depending on temperature and relative humidity. The delayed application of the second coat could result in its de-bonding.

Reinforcing Fabric … In some projects, REINFORCING FABRIC HD may have to be used throughout. When using REINFORCING FABRIC HD, apply first a thin layer of CEM-KOTE FLEX ST by brushing or spraying. When spraying, brush each coat to eliminate all pinholes. Embed REINFORCING FABRIC HD into the first coat and follow with a second coat. REINFORCING FABRIC HD must be fully covered and must not protrude through the surface. The total minimum applied thickness of CEM-KOTE FLEX ST, including REINFORCING FABRIC HD, must be 2 mm (80 mils).

Curing … Cure CEM-KOTE FLEX ST by air-drying for a minimum of three days prior to a continuous exposure to water. Protect fresh applications from rain, strong wind and intense sunlight for 12 hours. When working under tarps at freezing temperatures, use electrical heaters and forced venting. Avoid using propane heaters to prevent carbonation of the material.

Cleanup … All tools must be cleaned with water immediately after use. Cured material can only be removed mechanically.

PRECAUTIONS
Do not apply CEM-KOTE FLEX ST when the temperature is expected to be below 40° F (4°C) within 48 hours, or when rain is imminent. Follow hot weather concreting precautions when applying CEM-KOTE FLEX ST at temperatures exceeding 77°F (25° C) or under sunny and windy conditions.

CEM-KOTE FLEX ST is manufactured by:
Gemite Products, Inc.
1787 Drew Rd.
Mississauga, ON L5S 1J5
Canada

Tel. (888) 443-6483
Fax (888) 443-6329
Email techinfo@gemite.com
Web www.gemite.com

This material last updated August 2010.