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FULL PALLET USG Quick-Top (White) Self-Leveling Underlayment (56 bags)


About

USG Quick-Top (White) Self-Leveling Underlayment is an innovative self-sealing technology that sets and dries extremely quickly and typically eliminates the need to seal prior to applying the floor-covering adhesive.

Specs

  • Coverage: approx. 22 square feet
  • Compressive Strength: approx. 7,000 - 10,000 psi
  • Thickness Range: FE - 3 inches
  • Working Time: 25 minutes

Instructions

Subfloor Prep

All subfloors must be structurally sound, stable and solid. If there is any question about the structural soundness of the subfloor, consult with the engineer on the project or request the services of a professional structural engineer. Mechanical preparation is not required for most applications.

Subfloors must be clean and free of dirt, tar, wax, oil, grease, latex compounds, sealers, curing compounds, release agents, asphalt, water-soluble adhesives, paint, chemicals, loose old cementitious products, joint compounds from drywall installation or any other contaminant that might prevent proper bonding of underlayment. Clean all surface debris and dust by sweeping or vacuuming with a HEPA filtration industrial vacuum. Seal off floor drains before starting to pour underlayment to prevent drain pipes from clogging.

Fill deep areas and holes prior to final application. Contact USG for further information.

Contact USG for applications over vinyl asbestos tile (VAT).

To minimize the effect of expansion and cracking, wrap USG Levelrock® Perimeter Isolation Strip 2.5 (1/4 in. (6 mm) thick) around all door jambs, columns and pipes. For outside corners, the strip should extend a minimum of 24 in. (610 mm) from the corner on both sides. For more information on perimeter isolation strip installation, see USG Levelrock® Brand Perimeter Isolation Strip Submittal (IG1874).

Concrete Subfloors
Mechanical floor preparation such as shot-blasting, scarification or other methods of grinding may not be required prior to installation of the underlayment over a well-bonded, sound and clean subfloor. To decide whether mechanical preparation of substrate is required or not, the concrete substrate must be thoroughly assessed for its quality over the entire pour area. Simple visual appearance of the concrete substrate as strong and solid does not necessarily guarantee that the concrete substrate is free of impurities and has the right tensile strength.

A weak or degraded concrete surface or concrete exhibiting signs of laitance (either visible or invisible), scaling, spalling, crumbling or delamination must be mechanically removed to achieve a solid and clean substrate.

Concrete subfloors receiving cementitious underlayment systems must be cured properly (generally for a minimum of 28 days) prior to underlayment installation. Subfloor Moisture Vapor Emission Rate (MVER) exceeding 5 lbs. (2.3 kg)/1,000 sq. ft. (92.9 m2)/24 hours per ASTM F1869 or a relative humidity (RH) greater than 80% per ASTM F2170, must be treated with USG Durock™ Brand RH-100™ Moisture Vapor Reducer. USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments are not vapor barriers. Transmission of excessive moisture vapors from the concrete subfloor through USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can interfere with floor coverings and/or floor-covering adhesives, thus compromising their performance. If the concrete subfloor has been treated with USG Durock™ RH-100 Moisture Vapor Reducer, it must be primed with USG Durock™ Primer-Sealer prior to application of USG Durock™ Quik-Top White or Quik-Top Gray Self-Leveling Underlayment. See Priming section, pg. 3 for further details.

Cracks in the existing concrete subfloor must be inspected to determine if the crack is due to typical concrete “shrink” or if it is a result of a structural movement. In the case of the latter, remediation of the crack must be addressed or eventually the crack will telegraph through USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment. Consult with the engineer on the project or request the services of a professional structural engineer for all suspected structural cracks.

Repair all non-structural cracks in old and new concrete to minimize and control their ability to telegraph through the layer of USG Durock™ Quik-Top White or Gray Self-Leveling Underlayment. First remove the weak concrete along the length of the cracks by chiseling or other suitable means. Next, remove accumulated dust and debris from the crack cavities using a HEPA filtration industrial vacuum or other suitable means. Various cracks present in the concrete subfloor including shrinkage cracks must be filled with a suitable commercially available crack-fill epoxy adhesive designed for concrete flooring applications. To ensure superior resistance to crack growth, use injection epoxy crack-repair techniques per industry guidelines to repair cracks that are active or deep. Note that repair of existing cracks in the concrete subfloor only subdues, but does not completely prevent their ability to telegraph through USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment. Growth of existing cracks or formation of new cracks in the concrete subfloor can lead to cracks telegraphing through USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment. Respect existing expansion and control joints (see Notes/Limitations #8, pg. 6).

USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be installed over non-water-soluble adhesives on concrete only. The adhesive residue must first be tested to make certain it is non-water-soluble. Any water-soluble adhesive residues must be mechanically removed down to clean concrete. Non-water-soluble adhesive residues should be prepared to a thin, well-bonded residue using the “wet-scraping” technique as recommended by the Resilient Floor Covering Institute (rfci.com) to remove thick areas and adhesive buildup, as well as any areas that are weak or not well bonded to the concrete. Any existing patches below the adhesive must be completely removed. Subfloor must be properly prepared and primed prior to underlayment application.

Wood Subfloors
USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be applied without wire lath over engineer-approved, APA-rated exterior glue plywood or oriented strand board (OSB) (i.e., APA-Rated Exterior or Exposure 1 panels) wood subfloors. Joist spacing up to 24 in. (610 mm) o.c. requires a minimum ½ in. (13 mm) depth. Subfloor must be properly prepared and primed with USG Durock™ Brand Primer-Sealer. See Notes/Limitations #20, pg. 6 for subfloor deflections.

Gypsum Underlayments
Existing compromised gypsum underlayments must be solid. Loose, debonded gypsum underlayment must be completely removed until a sound bonding surface remains. Using a stiff bristle broom, sweep the old gypsum surface while wearing proper dust protection. This will help to remove the old gypsum “scale” from the surface. It is highly recommended that a HEPA filtration industrial vacuum be used after sweeping to remove as much dust as possible. Next, prime the surface with either USG Durock™ Primer-Sealer or Fusion™ Primer per the application instructions. For more information about the use of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments as a repair treatment for compromised gypsum underlayments, please see USG Rehabilitation Guidelines for Damaged Gypsum Underlayments (CB822).

Structural Concrete Panels
USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be applied over USG Structural Panel Concrete Subfloors. For joist spacing up to 24 in. (610 mm) o.c., a minimum ½ in. (13 mm) depth is required. Subfloor must be properly prepared and primed with USG Durock™ Brand Primer-Sealer per the non-porous application instructions. For more information, see USG Structural Panel Concrete Subfloor Submittal (SCP3) at usg.com. See Notes/Limitations #20, pg. 6 for subfloor deflections.

Existing Floor Coverings
For the application of USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment over existing floor coverings on concrete subfloors such as ceramic tile, vinyl composition tile (VCT), cement terrazzo and thin cutback adhesive, the surface needs to be well bonded, sound and clean.

Tiles that exhibit a bubbled surface or that are debonding from the substrate are not suitable surfaces for receiving pre-sanded floor underlayments. These floor-covering surfaces need to be removed and the substrate inspected for potential water damage. If water damage is detected, the source of the moisture needs to be identified and addressed. These areas should be checked for MVER using the ASTM F1869 test method or for RH using the ASTM F2170 test method (see Concrete Subfloors, pg. 2). Depending on the MVER ratings, the subfloor may need to be treated with USG Durock™ RH-100 Moisture Vapor Reducer.



Priming

Use the appropriate USG Durock™ Brand primer for preparing the subfloor prior to application of USG Durock™ Quik-Top White or Quik-Top Gray Self-Leveling Underlayments (see specific subfloor sections above). Proper use of USG Durock™ primers enhance the bond of the underlayment and effectively seals the subfloor and prevents formation of pinholes, domes and craters in USG Durock™ Quik-Top White or Quik-Top Gray Self-Leveling Underlayments due to the upward migration of air bubbles from the subfloor. Refer to submittal sheets USG Durock™ Brand PrimerSealer (CB519), USG Durock™ Brand ESB™ Primer (CB800), USG Durock™ Brand EW2™ Primer (CB801) or USG Durock™ Brand Fusion™ Primer (CB836) at usg.com for installation instructions and application rates.

Floors to be primed must be dry, structurally sound and clean. Remove any dirt, tar, wax, oil, grease, latex compounds, sealers, curing compounds, release agents, asphalt, water-soluble adhesives, paint, chemicals, loose topping, joint compounds from drywall installation or any other contaminant that might interfere with development of good bond.

For primer application, the temperature of the USG Durock™ primer, subfloor and room must be maintained between 50-95 °F (10-35 °C) for a period of 48 hours before and after application.



Mixing

Tools

  • Mixing drum (15 gallons)
  • Gage rake
  • Smoother/spreader
  • Nonmetallic cleated shoes
  • Measuring bucket
  • Mixing drill type 2 through 7—as outlined in the Technical Guidelines prepared by the International Concrete Repair Institute, Pictorial Atlas of Concrete Repair Equipment (Guideline No. 320.5R-2014)
  • Mixing paddle type 2, 3, 4, 8 or 9—as outlined in the Technical Guidelines prepared by the International Concrete Repair Institute, Pictorial Atlas of Concrete Repair Equipment (Guideline No. 320.5R-2014)
  • 1 in. x 2 in. (25 mm x 51 mm) brass or plastic cylinder • 12 in. x 12 in. x 1/4 in. (305 mm x 305 mm x 6 mm) Plexiglas® sheet
  • Minimum 2 in. (51 mm) putty/drywall taping knife
  • Ruler or tape measure

Barrel Mixing
When opening bags use engineering controls, including local exhaust, to reduce exposure to dust. Wear NIOSH-recommended respirator if needed. It is important that the mixing water for the total number of bags to be mixed is in the barrel prior to adding the dry material.

Determine the number of bags needed. Add 3.6 - 5.0 quarts (3.4 - 4.75 liters) of cool, clean potable water for each 50 lb. (22.7 kg) bag of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayment powder to the dry mixing barrel. Next, slowly add one bag to the barrel while mixing. Mix for 30 seconds, making sure that all material is wetted out thoroughly. Slowly add the second and any additional bags to the mixing barrel while continuing to mix. Make sure the barrel sides are thoroughly scraped free of dry powder and that there is no unmixed material on the bottom of the barrel. Mix for an additional 90 seconds and ensure the material is uniform and lump free.

Perform a slump test on the material before application. See Test Procedures for instruction

Do not add additional water until the two-minute mixing cycle has been completed. Do not overwater the material. If additional water is required, add no more than 0.5 quarts (0.47 liters) per bag and mix for 30 seconds or until mix is uniform. Do not overmix (more than three minutes), as this may induce air into the material.

The presence of bleed water on the surface and/or material segregation (settling of sand) indicates overwatering. Adjust the amount of water added to the mix to prevent bleed water and material segregation.



Test Procedures

Slump Test
Set Plexiglas sheet on a level, stable surface, away from foot traffic. Ensure that the 1 in. x 2 in. (25 mm x 51 mm) cylinder is clean and dry. Place the cylinder in the middle of the Plexiglas sheet. Pour the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayment slurry into the cylinder, slightly overfilling it. Screed off the excess material from the top of the poured cylinder, away from the Plexiglas sheet. Lift the cylinder up smoothly to form the patty. Do not shake any excess slurry from the cylinder. Wait one minute and measure the patty in two directions 90° apart and calculate the average of the two measurements +/- 1/8 in. (3 mm) Ensure that the average patty diameter is within the 7 - 7-1/2 in. (178-191 mm) range for USG Durock™ Quik-Top White Self-Leveling Underlayment and 6-1/4 - 6-1/2 in. (159-165 mm) range for USG Durock™ Quik-Top Gray Self-Leveling Underlayment.



Application

During application and until the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments are firmly set (typically the first two hours immediately following the pour), close all doors, windows and other openings in the building and turn off HVAC systems to prevent air drafts. Thereafter, the HVAC system can resume, as well as the use of doors, windows and other openings. Light foot traffic can also occur after this time. High ambient humidity and deeper thicknesses will delay the drying process. Protect floors from heavy trade traffic loads (i.e., loaded drywall carts, heavy tool cabinets, etc.) with plywood. Protect installation areas from direct sunlight exposure for at least 24 hours.

USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments—either mixed or in powdered form—subfloor and room temperature must be between 50 °F and 95 °F (10-35 °C) at the time of application and for 72 hours after installation of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. For temperatures above 95 °F (35 °C), follow the American Concrete Institute's (ACI) Hot Weather Concrete Guidelines to ensure proper installation. If available water is not cool, chill water to 70 °F (21 °C).

When uncertain or unknown construction conditions are present on the job site, it is recommended to pour a small test area before conducting full installation. The test area must also include finish flooring to establish suitability of the complete system for intended use.

USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments have a flow time of approximately 25 minutes at 70 °F (21 °C). At higher temperatures the flow time is shortened; at lower temperatures the flow time is extended. Work as a team to obtain a satisfactory installation. Ensure continuous flow of slurry and promptly spread the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments to desired thickness and finish using a gage rake and a smoother. Perform these operations promptly to avoid trapping air bubbles, prevent formation of cold joints and achieve a satisfactory finish surface.

Apply the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments in an even ribbon along the short dimension of the room or area to be poured. Maintain a continuous wet edge. If pouring the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments against an edge that has been allowed to set, the edge of the previous pour should be treated with USG Durock™ Primer-Sealer.

Wear Surface Application

  • USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be used as a wear surface with a protective coating system.
  • USG Durock™ Quik-Top Gray Self-Leveling Underlayments can provide a concrete look when used with a clear coating system.
  • USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be integrally colored or stained using a tested stain and either polished or sealed with a protective coating system.
  • Coating systems must be tested for adhesion to USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. The bond test and performance of coatings are the responsibility of the coating manufacturer. Contact USG for further information regarding decorative coating options.



Floor Covering Installation

  • USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be walked on two hours after installation.
  • Floor coverings can typically be installed after 15 hours when USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments are applied at a 1 in. (25 mm) thickness or less. Drying time will vary depending on underlayment thickness and ambient climate conditions.
  • Check with floor-covering and adhesive manufacturers for installation guidelines and suitability of their manufactured products over USG Durock™ Quik-Top White and Quik-Top Gray SelfLeveling Underlayments.
  • Perform field bond test to determine adhesive/flooring performance over USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. Install floor covering with adhesive and perform field bond test approximately 72 hours after installation.
  • Follow floor-covering manufacturers' recommendations for surface-sealing requirements. If the floor-covering or adhesive manufacturer requirements are more stringent, their requirements take precedence.

For further details on installation requirements, specifications and the most up-to-date product information, please see usg.com.


Limitations

  1. Do not use in exterior applications.
  2. USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be used as a wear surface with a tested decorative, protective coating system. Coating systems must be tested for adhesion to USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. The bond test and performance of coatings are the responsibility of the coating manufacturer. Contact USG for further information regarding decorative coating options.
  3. Do not install where continuous exposure to moisture is a possibility.
  4. Do not install over dimensionally unstable, improperly prepared, weak subfloors.
  5. Do not install over concrete subfloor less than 28 days old. For untreated (without an approved moisture mitigation system) concrete subfloors less than 28 days old, contact USG.
  6. For below-grade applications, contact USG.
  7. Contact USG for use over sound mats.
  8. Do not use over expansion or isolation joints. Continue all movement joints in the concrete slab up through the layer of underlayment. In areas where the expansion or isolation joints are not present in the floor or where the concrete slab has developed systematic cracks in response to slab movement, consult with an engineer on the project or request services of a professional structural engineer to provide such joints as part of the system in accordance with engineering requirements and industry standards.
  9. Existing cracks in the new and old concrete must be repaired with an appropriate crack-repair material in accordance with industry recommendations prior to installation of the underlayment. Note that repair of existing cracks in the concrete subfloor only subdues but does not completely prevent their ability to telegraph through USG Durock™ Quik-Top White and Quik-Top Gray SelfLeveling Underlayments. Growth of existing cracks or formation of new cracks in the concrete subfloor can lead to cracks telegraphing through the poured underlayment.
  10. When the MVER exceeds 5 lbs. (2.3 kg)/1,000 sq. ft. (92.9 m2 )/24 hours or an RH greater than 80% per ASTM F2170, treat the concrete subfloor with USG Durock™ RH-100 Moisture Vapor Reducer. USG Durock™ Quik-Top White and Gray Self-Leveling Underlayments are not a vapor or moisture barrier. Transmission of excessive water vapor or moisture from the concrete subfloor through the USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment can interfere with floor coverings and/or floor-covering adhesives, thus compromising their performance. For on-grade applications, use USG Durock™ RH-100 Moisture Vapor Reducer over concrete. Moisture mitigation system may not be needed if a vapor retarder is installed below the concrete slab in accordance to industry specifications and practice (ASTM E1745, ASTM E1993, ASTM E1693) and the MVER value of the concrete slab is below 5 lbs. (2.3 kg)/1,000 sq. ft. (92.9 m2 )/24 hours or has an RH less than 80% per ASTM F2170.
  11. Do not use acid etching as a method of cleaning and preparing the concrete subfloor.
  12. Do not use oil-based sweeping compounds to clean and prepare the concrete subfloor. Use of such sweeping compounds leaves an oil film on the surface of the concrete that will interfere with the underlayment's bond development. Use a HEPA filtration industrial vacuum to remove the dust and debris and prepare the subfloor for USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayment application.
  13. Do not use adhesive-removing chemicals or solvents to eliminate contaminants from the concrete subfloor. Use of such chemicals can transport oil, grease and other contaminants further into the concrete pores. These chemicals can be released back to the surface at a later time to interfere with the floor-covering adhesives, thus compromising the bond performance with USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. Mechanically removing the organic adhesives, asphalt, coal-tar-based adhesives and other oil-based contaminants is the sole recommended method of preparing the subfloor for application of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. 
  14. Contact USG for applications of USG Durock™ gypsum-based cement self-leveling underlayments over asbestos tiles. Do not mechanically remove organic adhesives, asphalt, coal-tar-based adhesives or other materials containing asbestos.
  15. Do not overwater or over mix.
  16. Do not add any chemical additives or polymers to USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments.
  17. Do not use wet curing or curing compounds.
  18. Do not mix with other cementitious products or self-leveling materials.
  19. Differential or excessive movement of the wood subfloor may lead to development of cracks in USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments at the wood subfloor joints and adjacent areas.
  20. Structure shall be designed so deflection does not exceed L/240 from combined dead and live loads and L/360 from live loads. Certain floor coverings such as marble, limestone, travertine and wood may have more restrictive deflection limits. Consult the appropriate floorcovering manufacturer.
  21. Existing gypsum underlayments must be solid with no cracks and dust free. Gypsum underlayment must be sealed with USG Durock™ Primer-Sealer or Fusion Primer. First test surface hardness by scratching existing underlayment with a coin. If surface can be gouged, please see USG Rehabilitation Guidelines for Damaged Gypsum Underlayments (CB822) for alternative repair methods.
  22. For thicknesses greater than 1 in. (25 mm), contact USG for special application instructions.
See More

FULL PALLET USG Quick-Top (White) Self-Leveling Underlayment (56 bags)

Quantity must be 1 or more
Regular price
$2,440.00
Sale price
$2,440.00
Provides a smooth, hard underlayment surface over concrete, wood, gypsum underlayments and well-bonded existing floor coverings.
  • FREE Freight to any commercial address in the lower 48
  • Each pallet contains (56) 50 lb bags
  • Additional fees are possible for job-site, residential, or remote location delivery
  • Dry within 15 hours so applicators can pour and cover in the same day
  • Require minimal subfloor surface preparation and no shot blasting

About

USG Quick-Top (White) Self-Leveling Underlayment is an innovative self-sealing technology that sets and dries extremely quickly and typically eliminates the need to seal prior to applying the floor-covering adhesive.

Specs

  • Coverage: approx. 22 square feet
  • Compressive Strength: approx. 7,000 - 10,000 psi
  • Thickness Range: FE - 3 inches
  • Working Time: 25 minutes

Instructions

Subfloor Prep

All subfloors must be structurally sound, stable and solid. If there is any question about the structural soundness of the subfloor, consult with the engineer on the project or request the services of a professional structural engineer. Mechanical preparation is not required for most applications.

Subfloors must be clean and free of dirt, tar, wax, oil, grease, latex compounds, sealers, curing compounds, release agents, asphalt, water-soluble adhesives, paint, chemicals, loose old cementitious products, joint compounds from drywall installation or any other contaminant that might prevent proper bonding of underlayment. Clean all surface debris and dust by sweeping or vacuuming with a HEPA filtration industrial vacuum. Seal off floor drains before starting to pour underlayment to prevent drain pipes from clogging.

Fill deep areas and holes prior to final application. Contact USG for further information.

Contact USG for applications over vinyl asbestos tile (VAT).

To minimize the effect of expansion and cracking, wrap USG Levelrock® Perimeter Isolation Strip 2.5 (1/4 in. (6 mm) thick) around all door jambs, columns and pipes. For outside corners, the strip should extend a minimum of 24 in. (610 mm) from the corner on both sides. For more information on perimeter isolation strip installation, see USG Levelrock® Brand Perimeter Isolation Strip Submittal (IG1874).

Concrete Subfloors
Mechanical floor preparation such as shot-blasting, scarification or other methods of grinding may not be required prior to installation of the underlayment over a well-bonded, sound and clean subfloor. To decide whether mechanical preparation of substrate is required or not, the concrete substrate must be thoroughly assessed for its quality over the entire pour area. Simple visual appearance of the concrete substrate as strong and solid does not necessarily guarantee that the concrete substrate is free of impurities and has the right tensile strength.

A weak or degraded concrete surface or concrete exhibiting signs of laitance (either visible or invisible), scaling, spalling, crumbling or delamination must be mechanically removed to achieve a solid and clean substrate.

Concrete subfloors receiving cementitious underlayment systems must be cured properly (generally for a minimum of 28 days) prior to underlayment installation. Subfloor Moisture Vapor Emission Rate (MVER) exceeding 5 lbs. (2.3 kg)/1,000 sq. ft. (92.9 m2)/24 hours per ASTM F1869 or a relative humidity (RH) greater than 80% per ASTM F2170, must be treated with USG Durock™ Brand RH-100™ Moisture Vapor Reducer. USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments are not vapor barriers. Transmission of excessive moisture vapors from the concrete subfloor through USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can interfere with floor coverings and/or floor-covering adhesives, thus compromising their performance. If the concrete subfloor has been treated with USG Durock™ RH-100 Moisture Vapor Reducer, it must be primed with USG Durock™ Primer-Sealer prior to application of USG Durock™ Quik-Top White or Quik-Top Gray Self-Leveling Underlayment. See Priming section, pg. 3 for further details.

Cracks in the existing concrete subfloor must be inspected to determine if the crack is due to typical concrete “shrink” or if it is a result of a structural movement. In the case of the latter, remediation of the crack must be addressed or eventually the crack will telegraph through USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment. Consult with the engineer on the project or request the services of a professional structural engineer for all suspected structural cracks.

Repair all non-structural cracks in old and new concrete to minimize and control their ability to telegraph through the layer of USG Durock™ Quik-Top White or Gray Self-Leveling Underlayment. First remove the weak concrete along the length of the cracks by chiseling or other suitable means. Next, remove accumulated dust and debris from the crack cavities using a HEPA filtration industrial vacuum or other suitable means. Various cracks present in the concrete subfloor including shrinkage cracks must be filled with a suitable commercially available crack-fill epoxy adhesive designed for concrete flooring applications. To ensure superior resistance to crack growth, use injection epoxy crack-repair techniques per industry guidelines to repair cracks that are active or deep. Note that repair of existing cracks in the concrete subfloor only subdues, but does not completely prevent their ability to telegraph through USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment. Growth of existing cracks or formation of new cracks in the concrete subfloor can lead to cracks telegraphing through USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment. Respect existing expansion and control joints (see Notes/Limitations #8, pg. 6).

USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be installed over non-water-soluble adhesives on concrete only. The adhesive residue must first be tested to make certain it is non-water-soluble. Any water-soluble adhesive residues must be mechanically removed down to clean concrete. Non-water-soluble adhesive residues should be prepared to a thin, well-bonded residue using the “wet-scraping” technique as recommended by the Resilient Floor Covering Institute (rfci.com) to remove thick areas and adhesive buildup, as well as any areas that are weak or not well bonded to the concrete. Any existing patches below the adhesive must be completely removed. Subfloor must be properly prepared and primed prior to underlayment application.

Wood Subfloors
USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be applied without wire lath over engineer-approved, APA-rated exterior glue plywood or oriented strand board (OSB) (i.e., APA-Rated Exterior or Exposure 1 panels) wood subfloors. Joist spacing up to 24 in. (610 mm) o.c. requires a minimum ½ in. (13 mm) depth. Subfloor must be properly prepared and primed with USG Durock™ Brand Primer-Sealer. See Notes/Limitations #20, pg. 6 for subfloor deflections.

Gypsum Underlayments
Existing compromised gypsum underlayments must be solid. Loose, debonded gypsum underlayment must be completely removed until a sound bonding surface remains. Using a stiff bristle broom, sweep the old gypsum surface while wearing proper dust protection. This will help to remove the old gypsum “scale” from the surface. It is highly recommended that a HEPA filtration industrial vacuum be used after sweeping to remove as much dust as possible. Next, prime the surface with either USG Durock™ Primer-Sealer or Fusion™ Primer per the application instructions. For more information about the use of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments as a repair treatment for compromised gypsum underlayments, please see USG Rehabilitation Guidelines for Damaged Gypsum Underlayments (CB822).

Structural Concrete Panels
USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be applied over USG Structural Panel Concrete Subfloors. For joist spacing up to 24 in. (610 mm) o.c., a minimum ½ in. (13 mm) depth is required. Subfloor must be properly prepared and primed with USG Durock™ Brand Primer-Sealer per the non-porous application instructions. For more information, see USG Structural Panel Concrete Subfloor Submittal (SCP3) at usg.com. See Notes/Limitations #20, pg. 6 for subfloor deflections.

Existing Floor Coverings
For the application of USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment over existing floor coverings on concrete subfloors such as ceramic tile, vinyl composition tile (VCT), cement terrazzo and thin cutback adhesive, the surface needs to be well bonded, sound and clean.

Tiles that exhibit a bubbled surface or that are debonding from the substrate are not suitable surfaces for receiving pre-sanded floor underlayments. These floor-covering surfaces need to be removed and the substrate inspected for potential water damage. If water damage is detected, the source of the moisture needs to be identified and addressed. These areas should be checked for MVER using the ASTM F1869 test method or for RH using the ASTM F2170 test method (see Concrete Subfloors, pg. 2). Depending on the MVER ratings, the subfloor may need to be treated with USG Durock™ RH-100 Moisture Vapor Reducer.



Priming

Use the appropriate USG Durock™ Brand primer for preparing the subfloor prior to application of USG Durock™ Quik-Top White or Quik-Top Gray Self-Leveling Underlayments (see specific subfloor sections above). Proper use of USG Durock™ primers enhance the bond of the underlayment and effectively seals the subfloor and prevents formation of pinholes, domes and craters in USG Durock™ Quik-Top White or Quik-Top Gray Self-Leveling Underlayments due to the upward migration of air bubbles from the subfloor. Refer to submittal sheets USG Durock™ Brand PrimerSealer (CB519), USG Durock™ Brand ESB™ Primer (CB800), USG Durock™ Brand EW2™ Primer (CB801) or USG Durock™ Brand Fusion™ Primer (CB836) at usg.com for installation instructions and application rates.

Floors to be primed must be dry, structurally sound and clean. Remove any dirt, tar, wax, oil, grease, latex compounds, sealers, curing compounds, release agents, asphalt, water-soluble adhesives, paint, chemicals, loose topping, joint compounds from drywall installation or any other contaminant that might interfere with development of good bond.

For primer application, the temperature of the USG Durock™ primer, subfloor and room must be maintained between 50-95 °F (10-35 °C) for a period of 48 hours before and after application.



Mixing

Tools

  • Mixing drum (15 gallons)
  • Gage rake
  • Smoother/spreader
  • Nonmetallic cleated shoes
  • Measuring bucket
  • Mixing drill type 2 through 7—as outlined in the Technical Guidelines prepared by the International Concrete Repair Institute, Pictorial Atlas of Concrete Repair Equipment (Guideline No. 320.5R-2014)
  • Mixing paddle type 2, 3, 4, 8 or 9—as outlined in the Technical Guidelines prepared by the International Concrete Repair Institute, Pictorial Atlas of Concrete Repair Equipment (Guideline No. 320.5R-2014)
  • 1 in. x 2 in. (25 mm x 51 mm) brass or plastic cylinder • 12 in. x 12 in. x 1/4 in. (305 mm x 305 mm x 6 mm) Plexiglas® sheet
  • Minimum 2 in. (51 mm) putty/drywall taping knife
  • Ruler or tape measure

Barrel Mixing
When opening bags use engineering controls, including local exhaust, to reduce exposure to dust. Wear NIOSH-recommended respirator if needed. It is important that the mixing water for the total number of bags to be mixed is in the barrel prior to adding the dry material.

Determine the number of bags needed. Add 3.6 - 5.0 quarts (3.4 - 4.75 liters) of cool, clean potable water for each 50 lb. (22.7 kg) bag of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayment powder to the dry mixing barrel. Next, slowly add one bag to the barrel while mixing. Mix for 30 seconds, making sure that all material is wetted out thoroughly. Slowly add the second and any additional bags to the mixing barrel while continuing to mix. Make sure the barrel sides are thoroughly scraped free of dry powder and that there is no unmixed material on the bottom of the barrel. Mix for an additional 90 seconds and ensure the material is uniform and lump free.

Perform a slump test on the material before application. See Test Procedures for instruction

Do not add additional water until the two-minute mixing cycle has been completed. Do not overwater the material. If additional water is required, add no more than 0.5 quarts (0.47 liters) per bag and mix for 30 seconds or until mix is uniform. Do not overmix (more than three minutes), as this may induce air into the material.

The presence of bleed water on the surface and/or material segregation (settling of sand) indicates overwatering. Adjust the amount of water added to the mix to prevent bleed water and material segregation.



Test Procedures

Slump Test
Set Plexiglas sheet on a level, stable surface, away from foot traffic. Ensure that the 1 in. x 2 in. (25 mm x 51 mm) cylinder is clean and dry. Place the cylinder in the middle of the Plexiglas sheet. Pour the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayment slurry into the cylinder, slightly overfilling it. Screed off the excess material from the top of the poured cylinder, away from the Plexiglas sheet. Lift the cylinder up smoothly to form the patty. Do not shake any excess slurry from the cylinder. Wait one minute and measure the patty in two directions 90° apart and calculate the average of the two measurements +/- 1/8 in. (3 mm) Ensure that the average patty diameter is within the 7 - 7-1/2 in. (178-191 mm) range for USG Durock™ Quik-Top White Self-Leveling Underlayment and 6-1/4 - 6-1/2 in. (159-165 mm) range for USG Durock™ Quik-Top Gray Self-Leveling Underlayment.



Application

During application and until the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments are firmly set (typically the first two hours immediately following the pour), close all doors, windows and other openings in the building and turn off HVAC systems to prevent air drafts. Thereafter, the HVAC system can resume, as well as the use of doors, windows and other openings. Light foot traffic can also occur after this time. High ambient humidity and deeper thicknesses will delay the drying process. Protect floors from heavy trade traffic loads (i.e., loaded drywall carts, heavy tool cabinets, etc.) with plywood. Protect installation areas from direct sunlight exposure for at least 24 hours.

USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments—either mixed or in powdered form—subfloor and room temperature must be between 50 °F and 95 °F (10-35 °C) at the time of application and for 72 hours after installation of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. For temperatures above 95 °F (35 °C), follow the American Concrete Institute's (ACI) Hot Weather Concrete Guidelines to ensure proper installation. If available water is not cool, chill water to 70 °F (21 °C).

When uncertain or unknown construction conditions are present on the job site, it is recommended to pour a small test area before conducting full installation. The test area must also include finish flooring to establish suitability of the complete system for intended use.

USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments have a flow time of approximately 25 minutes at 70 °F (21 °C). At higher temperatures the flow time is shortened; at lower temperatures the flow time is extended. Work as a team to obtain a satisfactory installation. Ensure continuous flow of slurry and promptly spread the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments to desired thickness and finish using a gage rake and a smoother. Perform these operations promptly to avoid trapping air bubbles, prevent formation of cold joints and achieve a satisfactory finish surface.

Apply the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments in an even ribbon along the short dimension of the room or area to be poured. Maintain a continuous wet edge. If pouring the USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments against an edge that has been allowed to set, the edge of the previous pour should be treated with USG Durock™ Primer-Sealer.

Wear Surface Application

  • USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be used as a wear surface with a protective coating system.
  • USG Durock™ Quik-Top Gray Self-Leveling Underlayments can provide a concrete look when used with a clear coating system.
  • USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be integrally colored or stained using a tested stain and either polished or sealed with a protective coating system.
  • Coating systems must be tested for adhesion to USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. The bond test and performance of coatings are the responsibility of the coating manufacturer. Contact USG for further information regarding decorative coating options.



Floor Covering Installation

  • USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be walked on two hours after installation.
  • Floor coverings can typically be installed after 15 hours when USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments are applied at a 1 in. (25 mm) thickness or less. Drying time will vary depending on underlayment thickness and ambient climate conditions.
  • Check with floor-covering and adhesive manufacturers for installation guidelines and suitability of their manufactured products over USG Durock™ Quik-Top White and Quik-Top Gray SelfLeveling Underlayments.
  • Perform field bond test to determine adhesive/flooring performance over USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. Install floor covering with adhesive and perform field bond test approximately 72 hours after installation.
  • Follow floor-covering manufacturers' recommendations for surface-sealing requirements. If the floor-covering or adhesive manufacturer requirements are more stringent, their requirements take precedence.

For further details on installation requirements, specifications and the most up-to-date product information, please see usg.com.


Limitations

  1. Do not use in exterior applications.
  2. USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments can be used as a wear surface with a tested decorative, protective coating system. Coating systems must be tested for adhesion to USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. The bond test and performance of coatings are the responsibility of the coating manufacturer. Contact USG for further information regarding decorative coating options.
  3. Do not install where continuous exposure to moisture is a possibility.
  4. Do not install over dimensionally unstable, improperly prepared, weak subfloors.
  5. Do not install over concrete subfloor less than 28 days old. For untreated (without an approved moisture mitigation system) concrete subfloors less than 28 days old, contact USG.
  6. For below-grade applications, contact USG.
  7. Contact USG for use over sound mats.
  8. Do not use over expansion or isolation joints. Continue all movement joints in the concrete slab up through the layer of underlayment. In areas where the expansion or isolation joints are not present in the floor or where the concrete slab has developed systematic cracks in response to slab movement, consult with an engineer on the project or request services of a professional structural engineer to provide such joints as part of the system in accordance with engineering requirements and industry standards.
  9. Existing cracks in the new and old concrete must be repaired with an appropriate crack-repair material in accordance with industry recommendations prior to installation of the underlayment. Note that repair of existing cracks in the concrete subfloor only subdues but does not completely prevent their ability to telegraph through USG Durock™ Quik-Top White and Quik-Top Gray SelfLeveling Underlayments. Growth of existing cracks or formation of new cracks in the concrete subfloor can lead to cracks telegraphing through the poured underlayment.
  10. When the MVER exceeds 5 lbs. (2.3 kg)/1,000 sq. ft. (92.9 m2 )/24 hours or an RH greater than 80% per ASTM F2170, treat the concrete subfloor with USG Durock™ RH-100 Moisture Vapor Reducer. USG Durock™ Quik-Top White and Gray Self-Leveling Underlayments are not a vapor or moisture barrier. Transmission of excessive water vapor or moisture from the concrete subfloor through the USG Durock™ Quik-Top White and Gray Self-Leveling Underlayment can interfere with floor coverings and/or floor-covering adhesives, thus compromising their performance. For on-grade applications, use USG Durock™ RH-100 Moisture Vapor Reducer over concrete. Moisture mitigation system may not be needed if a vapor retarder is installed below the concrete slab in accordance to industry specifications and practice (ASTM E1745, ASTM E1993, ASTM E1693) and the MVER value of the concrete slab is below 5 lbs. (2.3 kg)/1,000 sq. ft. (92.9 m2 )/24 hours or has an RH less than 80% per ASTM F2170.
  11. Do not use acid etching as a method of cleaning and preparing the concrete subfloor.
  12. Do not use oil-based sweeping compounds to clean and prepare the concrete subfloor. Use of such sweeping compounds leaves an oil film on the surface of the concrete that will interfere with the underlayment's bond development. Use a HEPA filtration industrial vacuum to remove the dust and debris and prepare the subfloor for USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayment application.
  13. Do not use adhesive-removing chemicals or solvents to eliminate contaminants from the concrete subfloor. Use of such chemicals can transport oil, grease and other contaminants further into the concrete pores. These chemicals can be released back to the surface at a later time to interfere with the floor-covering adhesives, thus compromising the bond performance with USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. Mechanically removing the organic adhesives, asphalt, coal-tar-based adhesives and other oil-based contaminants is the sole recommended method of preparing the subfloor for application of USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments. 
  14. Contact USG for applications of USG Durock™ gypsum-based cement self-leveling underlayments over asbestos tiles. Do not mechanically remove organic adhesives, asphalt, coal-tar-based adhesives or other materials containing asbestos.
  15. Do not overwater or over mix.
  16. Do not add any chemical additives or polymers to USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments.
  17. Do not use wet curing or curing compounds.
  18. Do not mix with other cementitious products or self-leveling materials.
  19. Differential or excessive movement of the wood subfloor may lead to development of cracks in USG Durock™ Quik-Top White and Quik-Top Gray Self-Leveling Underlayments at the wood subfloor joints and adjacent areas.
  20. Structure shall be designed so deflection does not exceed L/240 from combined dead and live loads and L/360 from live loads. Certain floor coverings such as marble, limestone, travertine and wood may have more restrictive deflection limits. Consult the appropriate floorcovering manufacturer.
  21. Existing gypsum underlayments must be solid with no cracks and dust free. Gypsum underlayment must be sealed with USG Durock™ Primer-Sealer or Fusion Primer. First test surface hardness by scratching existing underlayment with a coin. If surface can be gouged, please see USG Rehabilitation Guidelines for Damaged Gypsum Underlayments (CB822) for alternative repair methods.
  22. For thicknesses greater than 1 in. (25 mm), contact USG for special application instructions.

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