Flooring Adhesives - SikaBond®-T21

All-in-One Wood Flooring Urethane Adhesive, Unlimited Moisture Vapor and Sound Reduction Membrane

SikaBond®-T21 is a one-component, low VOC, permanently elastic, super strong, very low permeability moisture-cure polyurethane adhesive, vapor retarding, crack bridging and sound reduction membrane all-in-one for full surface wood floor bonding.

• 270 % elongation
• Bonds up to 3/4" solid and engineered wood
• Extremely easy to trowel
• Unlimited subfloor moisture vapor protection
• No moisture testing required - a dry to touch substrate is the only requirement

• Crack bridging
• Low odor
• Excellent Green Grab
• Suitable for common types of wood flooring
• Creates sound reduction layer
• Especially good for problematic woods such as beech and bamboo
• Contains no water
• Eliminates sleepers and plywood over concrete and gypsum substrates
• Permanently elastic - allows planks to expand and contract without damage to the adhesive
• Tenacious bond

Usage

SikaBond®-T21 may be used for solid and engineered wood floors (strips, longstrips, planks, panels, boards), mosaic parquet, industrial parquet, wood paving (residential) as well as chip boards and plywood. Once cured, SikaBond®-T21 will generate a super strong bond to a variety of substrates for glue down installations and at the same time form a membrane which reduces moisture vapor transmission from the subfloor and sound reduction membrane.

Advantages

• 270 % elongation
• Bonds up to 3/4" solid and engineered wood
• Extremely easy to trowel
• Unlimited subfloor moisture vapor protection
• No moisture testing required - a dry to touch substrate is the only requirement

• Crack bridging
• Low odor
• Excellent Green Grab
• Suitable for common types of wood flooring
• Creates sound reduction layer
• Especially good for problematic woods such as beech and bamboo
• Contains no water
• Eliminates sleepers and plywood over concrete and gypsum substrates
• Permanently elastic - allows planks to expand and contract without damage to the adhesive
• Tenacious bond

Packaging

4 gal. (15.14 L)

Color

Light Brown

Product Details

Sustainability / Certifications / Approvals

APPROVALS / STANDARDS

• 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)

Product Information

Chemical Base

1-component polyurethane, moisture curing

Shelf Life

12 months from date of production

Storage Conditions

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)

Density

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)

Technical Information

Service Temperature

-40-158 °F (-40-70 °C)

Application

Application Information

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

Consumption

Coverage

• 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.

Application Steps

SUBSTRATE PREPARATION

SikaBond®-T21 can generally be used without priming on properly prepared, structurally sound concrete, cement floors, chipboards, ceramic tiles, plywood and hardwood. Sika recommends the use of Sika® MB over any dry, gypsum based subflooring to enhance surface strength. Maximum acceptable floor variation is 3/16 in. (4.7 mm) in 10 ft (3 m). 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. Remove laitance or weak areas mechanically. 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 adhesive or adhesive residue use Sika® MB - see Sika® MB 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 Sika® MB to help promote adhesion to the subfloor - or use and industry approved leveling compound over the cutback residue. SikaBond®-T21 will adhere to most common patching/ leveling compounds. Due to differences in asphalt based adhesive types and performance capabilities applicator must verify that preparation of the surface is sufficient prior to using Sika® MB or patch/ level compound.

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