PAREX® 121 Dry HI Basecoat & Adhesive

Please refer to table below to acheive desired impact classification.

* Achieve Higher Impact Classification with lower material cost and labor

12 months, 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.

• 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

Full adhesive bond strength is reached after 1–4 days, depending on humidity and temperature. Dries within 24 hours under normal drying conditions [70ºF (21ºC), 50% RH]. Cold and/or humid weather may extend drying time. SikaWall Accel-Pak may be added to decrease drying time. See Data sheet for more information.

Depending on the condition of the substrate and method of application, approximate coverages per bag are:
As an adhesive:

• 5/16 in. (8mm) notched trowel: 130-145 ft2 (12-13.5 m2)
• 5/8 in. (16mm) notched trowel: 80-95 ft2 (7.4-8.8 m2)
• 1/2 in. (12.7mm) notched trowel: 135-150 ft2 (12.5-14 m2)

As a basecoat to embed

• Parex 355 Standard Mesh: 105-125 ft2 (9.7-11.6 m2)
• SikaWall-9000 Intermediate 12 Mesh: 70-90 ft2 (6.5-8.3 m2)

As a double-layer basecoat to embed

• Parex 355 Standard Mesh and SikaWall-9005 Intermediate 6 Mesh: 35-55 ft2 (3.3-5.1 m2)

Planar irregularities are limited to 1/4 in. (6mm) or less in a 4 ft. (1.22 m) radius. Surface irregularities are limited to 1/4 in. (6mm) or less for masonry and concrete and 1/8 in. (3mm) or less for sheathing.

Irregular and uneven surface should be filled with any Parex 121 Basecoat & Adhesive.
Remove surface contaminants such as dust or dirt without damaging the substrate.
Painted substrates must have the paint removed with methods that result in no more than 10% of the remaining surface having paint.
For additional options for surface preparation, contact Sika Facades Technical Services Department.

• Use clean equipment for mixing and preparation.
• Add 5-6 quarts (4.7-5.7 L) of cool clean potable water to a 5 gal pail.
• Add half of the amount of 121 Dry HI Basecoat & Adhesive and mix to a homogenous consistency using a heavy-duty 1/2 in. (13 mm) drill with a rust-free paddle at 400-500 rpm.
• Then add the remaining half and mix until consistent.
• Small amounts of cool clean potable water may be added to adjust workability.
• Let the mixture stand for five minutes after initial mixing, then stir again, adding small amounts of water for workability once only.
• Parex 121 Dry HI Basecoat & Adhesive should be used immediately after mixing.
• Half batches may be mixed for convenience.
• Only Sika Facades approved additives can be added to this product.

Read the entire label before using this product.

• Adhesive Application: Apply the 121 Dry HI Basecoat & Adhesive to the entire surface on one face of the insulation board, using a 5/8 in. (16mm) notched trowel for masonry and concrete, or a 1/2-in. notched trowel for the WaterMaster System, or a 5/16 in. (8mm) notched trowel for sheathing. The adhesive ribbons should be of uniform thickness, run vertically when positioned on the wall (parallel to the 2 ft. [61 cm] board dimension), and reach the perimeter of the insulation board.
• To ensure high initial grab and uniform adhesive contact, apply insulation board to the wall with firm pressure to the entire surface.
• Apply sufficient pressure to flatten adhesive ridges. Glass mat sheathing requires extra pressure.
• Base coat Application: Rasp EPS board after 24 hours and when adhesive has fully cured and bonded.
• Using a stainless steel trowel, apply the 121 Dry HI Basecoat & Adhesive mixture to the rasped surface of the insulation board to a uniform thickness of 1/16 - 3/32 in. (1.5 - 2.4mm). Embed the Parex USA reinforcing mesh immediately in the wet 121 Dry HI Basecoat & Adhesive mixture. Smooth the surface of the 121 Dry HI Basecoat & Adhesive mixture with a trowel until the reinforcing mesh is fully embedded and the basecoat thickness is approximately 1/16 in. (1.5mm). The color of the reinforcing mesh should not be visible at the surface of the 121 Dry HI Basecoat & Adhesive material. A slight pattern of the mesh is acceptable, due to shrinkage of the cementitious Basecoat upon drying.
• As a leveler or filler: Apply Parex 121 Dry HI Basecoat & Adhesive and trowel to a smooth, uniform surface. Maximum thickness in a single application should be no more than 1/4 in. (6mm).
• When overlapping reinforcing mesh, special care must be taken to ensure the basecoat & mesh is flat, level and free from bumps. Basecoat should be feathered onto either side of the overlap.
• The mesh overlaps should be reviewed to ensure they are acceptably flat before proceeding.
• When SikaWall-9000 Intermediate 12 Mesh is used in a single layer, the SikaWall-9000 Intermediate 12 Mesh should be embedded into wet Parex 121 DRY HI Basecoat & Adhesive with edges and ends tightly abutted. Immediately following this procedure, SikaWall-9020 Detail Backwrap Mesh strips are centered over the butted ends and edges of the SikaWall-9000 Intermediate 12 Mesh reinforcing mesh. Embed the short detail mesh strips in base coat, troweling to a flat, flush surface covering the color of the detail mesh with base coat. Do not allow a build up of base coat thicker than on the surrounding SikaWall-9000 Intermediate 12 Mesh.
• Refer to Parex Technical Bulletin - Importance of Properly Backwrapping Drainage EIFS