Product Data Sheet
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PAREX® 121 Wet Basecoat & Adhesive

Dual use Basecoat & Adhesive

PAREX® 121 Wet Basecoat & Adhesive is used with Parex EIFS. It is a 100% acrylic adhesive and base coat that is field-mixed with Type I or Type II Portland cement (50% Acrylic paste to 50% cement ratio). As an adhesive it is used used to laminate EPS or XPS insulation to listed substrates.  

  • Trowels on easily, speeds mesh embedment, reduces applicator arm fatigue, increases jobsite productivity.
  • Smooth creamy consistency for easier application
  • Uses a famiilar 1:1 mixing ratio with porland cement making it easy to mix providing less chance for error.
  • 100% Acrylic.
  • Water based formulation for safer hanlding and easy clean up.
  • Provides long-term durability. Safe, non-toxic and cleans up easily with soap and water.
Product Data Sheet
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Usage

For reinforcing mesh embedment as part of Parex Systems and as a skim coat over masonry and concrete above grade substrates.

Advantages

  • Trowels on easily, speeds mesh embedment, reduces applicator arm fatigue, increases jobsite productivity.
  • Smooth creamy consistency for easier application
  • Uses a famiilar 1:1 mixing ratio with porland cement making it easy to mix providing less chance for error.
  • 100% Acrylic.
  • Water based formulation for safer hanlding and easy clean up.
  • Provides long-term durability. Safe, non-toxic and cleans up easily with soap and water.

Packaging

55 lb / 5 gal pail

Color

Off white prior to addition of Portland cement.

Product Details

Product Information

Shelf Life

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

Storage Conditions

  • 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.

Volatile organic compound (VOC) content

4 grams per liter
Technical Information

Tensile Strength

Test

METHOD

CRITERIA

RESULT

Tensile Bond

ASTM C297, E2134

15 psi minimum

>15 psi

Resistance to Weathering

Test

METHOD

CRITERIA

RESULT

Accelerated Weathering

ASTM G 23

No deleterious effects after 2000 hours.

Pass

Accelerated Weathering

ASTM G 53

No deleterious effects after 7500 hours.

Pass

Water resistance

Test

METHOD

CRITERIA

RESULT

Water Resistance of Coating in 100% R.H.

ASTM D 2247

No deleterious effects after 14 days exposure

Pass

Water Vapor Transmission

ASTM E96 Method B

Report Value

PAREX® 121 Wet Basecoat & Adhesive with Parex 355 and Parex DPR Finish: 15.1 Perms

  

Application

Application Information

Substrates

EPS adhesive for the following substrates:

  • Exterior grade gypsum sheathing
  • Glass mat gypsum sheathing
  • Masonry, concrete and cement board
  • EPS
  • Parex WeatherSeal Spray & Roll-On and WeatherSeal Trowel-On Water Resistive Barrier Coatings

Drying Time

As a leveler allow to cure 24 hours prior to finish application. As base coat for mesh embedment allow 8-10 hours.
PAREX® 121 Wet Basecoat & Adhesive achieves full strength in approximately 28 days. Protect from rain and temperatures of less than 40°F (4°C) for a minimum of 24 hours. Higher humidity and/or cooler temperatures may require longer protection.
Consumption

Coverage

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: 110-115ft2

Adhesive & Parex 355 Standard Mesh: 110ft2

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

SURFACE PREPARATION

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 6 days prior to application of base coat.

MIXING

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.  Mix one-part (by weight) Portland cement with one-part PAREX® 121 Wet Basecoat & Adhesive. Add Portland cement in small increments, thoroughly mixing to a homogeneous consistency after each additional increment. Let the mixture sit for 5-10 minutes then stir to a creamy consistency. Up to 32 oz. (0.9 L) of water per half pail, may be added to achieve the desired 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.
  • 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.
  • If Type 1-L Portland is used, contact Sika Facades Technical Service for approval.

APPLICATION

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 13 mm 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 SENERGY 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 (normally 8 to 10 hours) prior to application of PAREX® 121 Wet Basecoat & Adhesive/Reinforcing Mesh.

 

Note: Allow to cure for at least 24 hours before applying finish.

 
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 (normally 8 to 10 hours) prior to application Parex Finish or SikaWall-15 Tinted Primer.

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