Sag Flow

Consistency: Spreads very easily

Ambient Air Temperature

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.

Relative Air Humidity

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

Substrate Temperature

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.

Substrate Moisture Content

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.

Curing Rate

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

Skin Time / Laying Time