SikaBond®-T21

• Independently tested to STC = 62 as per ASTM E90 (6 in. concrete slab, 5/8 in. suspended gypsum ceiling)
• Independently tested to FIIC = 52 as per ASTM E989 (8 in. concrete slab, without ceiling)
• Reduction of Impact Sound Δ IIC = 21 as per ASTM E2179

1-component, moisture cured polyurethane

12 months from the date of production if stored properly

The product must be stored in original, unopened and undamaged sealed packaging in dry conditions and protected from direct sunlight at temperatures between 50°F and 77°F (10°C and 25°C).

~9.85 lbs/gal (~1.18 kg/L)

-40°F (-40°C) to 158°F (70°C)

Consistency: spreads very easily

Room temperature between 60°F (15°C) and 90°F (32°C). For ambient temperatures standard construction guidelines should be followed. Follow all floor covering manufacturers’ acclimation and room temperature requirements.

Between 40% and 70% during installation is best for adhesive. See floor covering manufacturer for floor covering requirements.

During laying and until SikaBond®-T21 has fully cured, substrate temperature should be greater than 60°F (15°C) and in the case of radiant floor heating, less than 68°F (20°C). For substrate temperatures, standard construction guidelines should be followed.

For use as an adhesive and all-in-one membrane: Concrete must be dry to touch. Inspect for any wetness at base of drywall or visible signs of moisture on concrete. Concrete and cement-based underlayments must be fully cured and free of any hydrostatic and/or moisture problems. When properly applied in accordance with Sika® guidelines, SikaBond®-T21 provides unlimited moisture vapor protection.

For use as an adhesive only: SikaBond®-T21 is not affected by moisture or vapor transmission. For protection of the floor covering, follow the floor covering manufacturer’s requirements for subfloor moisture. If substrate is not acceptable, use SikaBond®-T21 at recommended coverage rate as all-in-one or use Sika® MB. See Technical Data Sheet for proper instruction.

Floor may accept light foot traffic:

• at 45–50 SF/gal (P5 trowel) after 6–8 hours
• at 30–35 SF/gal (SC+MB trowel) after ~12 hours

Floor can be sanded after ~18 hours

Curing times depend on environmental and subfloor conditions, adhesive layer thickness and floor covering type.

45-60 minutes at 73°F (23°C) and 50% RH

• These are estimated spread rate coverages and additional adhesive may be required based on substrate porosity/profile/levelness, wastage or any other variations. Apply product to a test area to calculate the exact coverage for the specific substrate conditions. Trowel diagrams are not to scale.  
• Coverage must be monitored to ensure accuracy of application. Trowel angle may prevent proper coverage.
• Installer is responsible for periodic inspection of the trowel to check for excessive wear. Worn trowels must be replaced immediately.
• The above-listed trowels must be used to obtain proper coverage, larger sizes are acceptable. Excessive amounts of adhesive may cause floor covering to slide while placing, check coverage during installation.
• P5 trowels should be used at 90° angle, SC+MB trowel or 1/4 in. (6.3 mm) x 1/4 in. (6.3 mm) V-notch at 45° angle to subfloor to get stated coverages.
• The P5 and SC+MB trowel are available from Sika.

These directions are general guidelines for flooring installations. It is the responsibility of the installer to determine proper drying time of the adhesive, trowel size to be used and acceptability of subfloor conditions. All installations must be in accordance with the flooring manufacturer's recommendations. Only flooring that is approved in writing for glue down installations by the flooring manufacturer can be used with SikaBond®-T21. Floors installed with SikaBond®-T21 are not warranted against damage caused by wet mopping, flooding, plumbing leaks or other extraordinary circumstances. For any installation not herein recommended, contact Sika before proceeding.

Substrate must be clean and dry, homogeneous, even, free from oil, grease, dust and loose particles. Paint, laitance and other poorly adhering particles must be removed by mechanical means.

Note: Adhesion tests on project specific substrates are recommended to be performed.

• SikaBond®-T21 can be used on properly prepared, structurally sound concrete, cementitious patch/underlayments, chipboards, ceramic tiles, plywood. All floor covering manufacturer’s recommendations must be followed.
• Concrete substrate must have a concrete surface profile of CSP 1-3.
• For on-grade subfloors Sika recommends the use of Sika® MB, Sika® MB Redline or Sika® MB EZ Rapid for best protection against subfloor moisture – moisture testing is required by the floor covering manufacturer for best results with the floor covering products.
• Below grade applications are generally not recommended unless proper precautions are taken to protect the floor covering from subfloor and in-room humidity extremes.
• A 3,000 psi compressive strength is the minimum requirement needed for SikaBond® wood floor installations, including glue-down wood floors, or glued/mechanically anchored subfloors. Sika products such as Sika® MB, Sika® MB Redline or Sika® MB EZ Rapid can be used on substrates as consolidators to satisfy the minimum psi compressive strength requirements.
• Preparation is a critical step in the installation process and will ensure a successful long term tenacious bond.
• All subfloors must be structurally sound, clean, dry, smooth; free of voids, projections, loose materials, oil, grease, sealers and other surface contaminants. Thoroughly clean with an industrial vacuum. Remove laitance or weak areas mechanically and thoroughly.
• For application over ceramic tiles it is necessary to grind tile surfaces and clean thoroughly with an industrial vacuum.
• When installing floor covering over gypsum based substrates, the gypsum must first be sealed/primed with Sika® MB, Sika® MB Redline or Sika® MB EZ Rapid (see appropriate product data sheet for installation instructions and proper details).
• For substrates with old well bonded non-water soluble adhesive or adhesive residue use Sika® MB, Sika® MB Redline or Sika® MB EZ Rapid – see appropriate product data sheet for installation instructions and proper details. If surface contains asphalt (cutback) adhesive, follow the Resilient Floor Covering Institute “Recommended Work Practices” for removal. When the asphalt (cutback) adhesive is sufficiently removed use the Sika® MB, Sika® MB Redline or Sika® MB EZ Rapid to help promote adhesion to the subfloor or use a Sika® Level patch/level product in conjunction with the correct primer.
• SikaBond®-T21 will adhere to most common patching / levelling compounds. Due to differences in asphalt-based adhesive types and performance capabilities, installer must verify that preparation of the surface is sufficient prior to using Sika® MB or Sika® Level patch / level compound. For unknown substrates, please contact Sika® Technical Services for best practices at 1-800-933-SIKA.

All tools must be cleaned immediately after use with SikaBond® Remover or standard industry cleaning solvent. Any adhesive that is permitted to cure on the tool will need to be removed by mechanical means. SikaBond® Remover can be used to remove uncured or cured adhesive and fingerprints from wood surface.