RECOMMENDED SPECIFICATIONS

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PART I. GENERAL

1.1 Scope

Specify to meet project requirements. The conditions of the Contract (General, Supplementary, and other conditions) and the General Requirements (Sections of Division I) govern the provisions of this section.

1.2 Qualifications

1. Supplier: Hacker Industries, Inc., Newport Beach, California.
2. Installer: Installation of TRUE-SCREED® Cementitious Leveling Underlayment (CLU) shall be by a certified and trained, Licensed Applicator of Hacker Industries, Inc. using mixing and pumping equipment approved by Hacker Industries, Inc.
3. All materials specified herein shall be approved by Hacker Industries, Inc., Newport Beach, CA. All other must receive prior approval.
4. Compressive strengths should be specified up to 6000 psi (50.0 MPa).
5. Material shall be delivered in original, unopened bags. Material shall be stored away from prolonged exposure to harmful environmental conditions and at a minimum temperature of 50°F (10°C). Do not allow bags to get wet.
6. Certification: Upon completion of this portion of the work, and as a condition of its acceptance, deliver to the architect a certificate from Hacker Industries, Inc., and signed by the Licensed Applicator, stating that the material used in this work complies with the specified requirements.

PART II. PRODUCTS

2.1 Materials

1. Leveling Floor Underlayment: Floor underlayment compound shall be TRUE-SCREED® CLU as supplied by Hacker Industries, Inc., Newport Beach, CA.
2. Subfloor Primer: TRUE-SCREED® CLU Primer.
3. Sand: Sand shall meet the requirements of the TRUE-SCREED® CLU Sand Specification.
4. Water: Potable and free from impurities
5. Underlayment Sealer: TRUE-SCREED® CLU Sealer or approved equal.

PART III. PREPARATION

3.1 Surface Preparation

1. General Contractor shall confirm the subfloor is structurally sound, of adequate strength, and conditions are suitable for installation of a floor screed.
2. Acid etching and the use of sweeping compounds and solvents are not acceptable.
3. Limit design of the subfloor at a maximum of L/360 deflection.
4. Subfloor must be thoroughly cleaned and free of any substance that could interfere with the bond of TRUE-SCREED® CLU.
5. Concrete surfaces must be mechanically profiled and prepared using approved methods (reference ICRI CSP 2 standards for acceptable profile height).
6. Substrate hydrostatic pressure conditions and vapor transmission must not exceed 3 lbs. per square foot per 24 hours (1.4kg per 92.9m2 per 24 hours). Testing to be done per ASTM F1869 prior to application.
7. Ambient room temperature and concrete substrate should be maintained between 55-95°F (13-35°C). Temperatures must be maintained at this range for a minimum of 28 days.
8. Newly prepared substrates are subject to "out-gassing". Out-gassing cannot be detected visually and could cause problems with installation. Wait a minimum of 48 hours, after the substrate has been properly prepared. If the out-gassing is a result of moisture vapor transmission exceeding 3 lbs. per square foot per 24 hours (1.4kg per 92.9m2 per 24 hours) it must be treated prior to the installation of TRUE-SCREED® CLU.
9. All cracks in the subfloor shall be repaired to minimize telegraphing through the underlayment.

3.2 Priming

1. Always prime prepared surface with Hacker approved primer prior to installation of TRUE-SCREED® CLU per specifications.

3.3 Mix Design

TRUE-SCREED® CLU shall be installed using Hacker Industries, Inc. approved mixing and pumping equipment with a minimum of 110 feet (33m) of hose.

1. Mixer and pump must be clean per manufacturer's specifications and in good working condition.
2. Use a mesh screen at the end of the hose to catch any foreign material.
3. Mix in 2-bag batches.
4. Mix each bag of TRUE-SCREED® CLU with 3.75 gallons (4.2L) of cool potable water.
5. DO NOT OVERWATER!
6. Check the consistency of the product on the floor to ensure a uniform distribution of the sand aggregate at both the top surface and bottom of the pour. If settling is occurring, reduce the water amount and recheck.

3.4. Cementitious Underlayment Application

1. Scheduling: Application of TRUE-SCREED® CLU shall not begin until the building is enclosed, including roof, windows, and doors.
2. Application:
   1. Minimum thickness over wood - 3/4" (19mm) with mechanically fastened mesh reinforcement. 1/2" (13mm) minimum average thickness over concrete slabs, can be feather-edged. Maximum recommended thickness is 2" (51mm).
   2. Install TRUE-SCREED® CLU at specified thickness by placing contents of bags, sand and water into approved high-speed mixing device and blend for a minimum of 2 minutes. TRUE-SCREED® CLU should be pumped onto floor areas, spreading and screeding to a smooth surface. Place as continuously as possible.
   3. TRUE-SCREED® CLU is suitable for interior applications only and must be covered by a finished floor material.
3. Protection: After installation, temporary wood planking shall be placed wherever the floor underlayment will be subject to wheeled or concentrated loads.
4. Drying: TRUE-SCREED® CLU is designed to self-cure; do not use damp curing method and/or sealing compounds. To achieve the optimum floor please adhere to the following procedures:
   1. Protect the new floor from excessive heat and drafts during curing.
   2. Avoid walking on surface for at least 2-3 hours after installation, adjust for varying humidity and temperature conditions.
   3. Protect from traffic, dust and dirt from other trades until TRUE-SCREED® CLU is fully cured and the final floor covering has been installed. To protect, place temporary wood planking over the new floor.
5. Sealing: Seal all areas that receive glue down floor goods with TRUE-SCREED® CLU Sealer according to the Hacker Industries, Inc.'s specifications. Any floor areas where the surface has been damaged shall be cleaned and sealed regardless of floor covering to be used. Where floor good manufacturer requires special adhesive or installation systems, their requirements supercede these recommendations.

3.5 Field Quality Control

1. Slump Test: TRUE-SCREED® CLU mix shall be tested for slump as it is being pumped using a 2" by 4" (51mm by 102mm) cylinder and plexiglas.
2. Field Samples: Cubes shall be tested as recommended by Hacker Industries, Inc. in accordance with ASTM C109 modified. Test results shall be available to architect and/or contractor upon prior request from applicator.

True-Screed Cementitious Leveling Underlayment: Recommended Specifications

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