SikaBond®-T21

• Independently tested to -STC 62 (ASTM E-90) (6 in. (168 mm) concrete slab, 5/8 in. (19 mm) suspended gypsum ceiling)
• Independently tested to FIIC 52 (ASTM E-989) (8 in. (203 mm) concrete slab, without ceiling
• Reduction of Impact Sound Δ IIC = 21 (ASTM E-2179)

1-component polyurethane, moisture curing

12 months from date of production

Store in undamaged original sealed containers, in dry conditions and protected from direct sunlight at temperatures between 50 °F and 77 °F (10–25 °C)

Water Vapor Permeability    < 4 g/m2-24h-mmHg per ASTM E-96 (Standard Test Method for Water Vapor Transmission of Materials)

Specific Gravity  9.85 lbs/gal (1.18 kg/L)

-40–158 °F (-40–70 °C)

Consistency: Spreads very easily

Room temperature between 60 °F (15 °C) and 90 °F (35 °C). For ambient temperatures the standard construction rules are relevant. Follow all wood floor manufacturers’ acclimation and room temperature requirements.

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

During laying and until SikaBond®-T21 has fully cured, substrate temperature should be greater than 60 °F (15 °C) and in case of radiant floor heating, less than 70 °F (20 °C). For substrate temperatures, the standard construction rules are relevant.

For use as an adhesive and moisture membrane:
Concrete must be visibly dry. 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 wood, follow the wood floor manufacturer’s requirements for subfloor moisture. If substrate is not acceptable, use SikaBond®-T21 at recommended coverage rate as All-in-One or Sika® MB. See Technical Data Sheet for proper instruction.

Floor may accept light foot traffic after:

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

(depending on climatic conditions and adhesive layer thickness)

Floor can be sanded after 18 hours

• Coverage must be monitored to ensure accuracy of application. Trowel angle may prevent proper coverage.
• Applicator is responsible for periodic inspection of the trowel to check for excessive wear. Worn trowels must be replaced immediately.
• In case of uneven substrates, it may be necessary to use a notched trowel with bigger notches (avert hollow sections).
• Coverage must be monitored to ensure accuracy of application. Trowel angle may prevent proper coverage.
• Trowel size is recommended to obtain proper coverage larger sizes are acceptable. Excessive amounts of adhesive may cause wood flooring 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.
• Substrate Quality: Structurally sound, clean, dry, homogeneous, even, free from grease, dust and loose particles, paint, laitance, and other poorly adhering particles must be removed.
• The P5 and SC+MB trowel are available from Sika.

• SikaBond®-T21 can be used on properly prepared, structurally sound concrete, cementitious patch/underlayments, chipboards, ceramic tiles, plywood.
• 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, and Sika® MB EZ Rapid for best protection against sub-floor moisture – moisture testing is required by the wood flooring manufacturer for best results with the wood flooring products.
• Below grade applications are generally not recommended unless proper precautions are taken to protect the wood flooring from sub-floor 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 SikaLevel®-01 Primer Plus, Sika® MB, Sika® MB Redline, and 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 concrete, cement screed and gypsum based 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.
• 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, applicators 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.