PAREX® 121 Wet Basecoat & Adhesive

Two (2) years, when properly stored in original container.

• Protect materials during transportation to avoid physical damage. Store in a cool, dry place protected from freezing, extreme heat and direct sun. Store at no less than 40°F (4°C).
• Do not stack pallets.

• When temperatures less than 40°F (4°C) prevail, provide supplementary heat during installation and drying period for at least 24 hours after installation and until dry.
• Do not apply in ambient temperature above 100°F (38°C) or surface temperature above 120°F (49°C).

To adhere EPS, GPS and DuPont™ Styrofoam™ Panel Core 20 to the following substrates:

• Parex WeatherSeal Spray and Roll On
• Cement boards conforming with ASTM C1325 (Type A - exterior) including PermaBase® Cement Board
• Poured in place concrete/ concrete unit masonry
• ASTM C1177 type sheathings, including DensGlass™ or DensElement exterior sheathing (sheathing only), eXP™ sheathing, GlasRoc® sheathing, Securock™ glass-mat sheathing, Weather Defense™ Platinum sheathing, GreenGlass® sheathing
• Gypsum sheathing (ASTM C1396)
• Exposure 1 or exterior plywood (Grade C/D or better) and Exposure 1 OSB; requires WeatherSeal

Skim Coat/Mesh Embedment: Poured in place concrete / concrete unit masonry; stucco; approved rigid insulation; ASTM C1177 and ASTM C1325 type sheathings (soffits/ceiling only)

Under average conditions of 70 °F (21 °C) and 50% Relative Humidity:

• Base coat will typically be fully dry in 24 hours.
• Drying time is dependent on humidity, air temperature, sun exposure, surface conditions and product thickness. Lower temperature, higher humidity and application in shaded areas will extend drying time.
• Protect applied material from rain or other precipitation and temperatures less than 40°F (4°C) for a minimum of 24 hours or until dry.

Coverages per pail

Adhesive

Notch trowel: 145-150 ft²

Mesh Embedment

Parex 355 Standard Mesh: 255-260 ft²

SikaWall^®-9000 Intermediate 12: 185-190ft²

SikaWall -9015 Ultra Hi 20 & Parex 355 Standard Mesh: 115-120ft²

Adhesive & Parex 355 Standard Mesh: 110ft²

* Coverage rates vary depending on porosity of substrates and application techniques.

Substrates must be clean, dry, sound and free of loose material, releasing agents, paint, efflorescence, contaminants and bond inhibiting coatings. 

• Concrete: allow to cure a minimum of 28 days prior to application of base coat.
• Unit Masonry: allow to cure prior to application of base coat.
• Stucco: allow to cure a minimum of 7 days prior to application of base coat.

In a clean container, mix the contents of the PAREX® 121 Wet Basecoat & Adhesive pail with a low speed drill and paddle mixer until thoroughly blended. Divide pail content in two equal parts, mix 30 lbs. (13.6 kg) of PAREX® 121 Wet Basecoat & Adhesive with 30 lbs. (13.6 kg) of Type I, IL or II Portland cement in small increments; thoroughly mix to a homogeneous consistency after each additional increment. Let the mixture sit for 5 minutes then stir to a creamy consistency. A small amount (up to 15 oz) of water can be added to adjust workability

• Do not use a container which has contained or been cleaned with a petroleum based product.
• Do not overmix. Excessive stirring will cause faster setting of the PAREX® 121 Wet Basecoat & Adhesive and significantly reduce working time.
• For best results, mix at 400-500 rpm, using a heavy-duty drill with a jiffler type paddle (Goldblatt Jiffler Mixer No. 15311 H7 or similar).
• Additives are not permitted.
• Close container when not in use.
• Clean tools with soap and water immediately after use. Dried material can only be removed mechanically

ADHESIVE FOR NON-DRAINAGE EIFS/EPS TO EPS
Notched trowel method: Apply base coat to entire surface of insulation board using a stainless steel trowel with 1/2” x 1/2” notches spaced 1/2” apart (13 mm x 13mm x 13 mm) or 3/8” x 3/8” notches spaced 3/8” apart (10 mm x 10 mm x 10 mm).

ADHESIVE FOR ADHERED PAREX DRAINAGE EIFS
Apply base coat to entire surface of insulation board using a stainless-steel trowel with 1/2”x 1/2” notches spaced 2” apart (13 mm x 13 mm x 50 mm). Ribbons of adhesive must be applied parallel to the 2’ dimension of the EPS insulation board to ensure they are vertical when the EPS insulation board is applied to the substrate. Immediately set board into place and apply pressure over entire surface of board to ensure
positive uniform contact and high initial grab. Do not slide board into place. Do not allow base coat to dry prior to installing. Allow application of EPS insulation board to dry prior to application of PAREX® 121 Wet Basecoat & Adhesive/Reinforcing Mesh.

APPLICATION AS BASE COAT FOR REINFORCING MESH EMBEDMENT
Trowel apply base coat to the surface of the insulation board or approved substrate. Fully embed reinforcing mesh into wet base coat, ensure no mesh color is visible. Lap reinforcing mesh a minimum 2 ½” (64 mm) at edges and 8” (203 mm) around corners. Ensure reinforcing mesh is free of wrinkles. Allow reinforced base coat to dry hard prior to application Parex Finish or SikaWall-15 Tinted Primer.

Consult Sika Facades Technical Services Department at +1 (800) 266-2424 for specific recommendations concerning all other applications.