Master Wall® Cemplaster Fiberstucco is a fibered Portland cement-based bagged stucco with exceptional workability, open working time, water  retention, early strength, shrinkage resistance and long-term durability.

  • Concentrate, mix with sand and water
  • Fibered for better crack resistance
  • Can be modified with Stucco Ad-Liquid for better tensile, compression and mold-resistance
  • For application over lath or direct-applied to approved substrates
  • Manufacturer Warranty


VOC: <1% by Weight VOC: 0 g/l 3% Recycled Content Manufacture Locations: 29059

Cemplaster Fiberstucco

Product Test Standards
ASTM C109, ASTM E330, ASTM G155, ICC-ES AC11

Packaging: 80 lb (36 kg) Bag

Working Time: 1-1/2 hours @ room temperature

Curing Time: 24 hours @ room temperature

Shelf Life: 1 year

Coverage (estimated)

3/8” (9.5 mm) thick: 80 sf (7.4 sm)

1/2” (12.7 mm) thick: 70 sf (6.5 sm)

3/4” (19 mm) thick: 40 sf (3.7 sm)

7/8” (22 mm) thick: 34 sf (3.1 sm)

Approved Substrates
2.5#/sy self-furring metal lath and other approved metalic or plastic lath
Others approved in writing

Temp: 40°-110°F (5°-43°C)

Working Time: 1.5 hr

Curing Time: 24 hrs*
*at room temperature, working and drying time will vary with temperature and humidity

Application Procedure

Job Conditions – Air and substrate temperature for application of Cemplaster Fiberstucco must be 40°F (5°C) or higher and must remain 40°F (5°C) or higher for a minimum of 24 hours. Provide temporary protection to protect the wall system from damage until permanent flashings, caps and sealants are installed. Store materials in a dry place, within prescribed temperature limits and out of direct sunlight. Working and drying times are based upon normal room temperature conditions and will vary with temperature and humidity.

Preparation – The substrate must be approved by Master Wall Inc.®, clean, dry, structurally sound and free of efflorescence, oil, grease, form release agents and curing compounds or anything that would affect bond. Painted surfaces are not acceptable and must be removed or metal lath applied. All sheathed applications must receive a minimum of 2-layers code-approved asphalt felt or equivalent.

Prepare smooth or non-absorbent solid substrates by one of the following methods or a combination; Sandblasting, chipping or acid etching, A dash-bond coat applied forcefully, Bonding compounds such as Master Wall® Stucco Ad-Liquid or BA57, Furred or self-furring metal plaster bases as per ASTM C1063.

Mixing – Each bag of Cemplaster Fiberstucco is mixed with 200 lbs (90.7 kg) of sand aggregate (ASTM C897 or ASTM C144) and clean, potable water (200 lbs is roughly 2.5 cubic feet (0.07 cubic meters) of clean, damp-loose sand or 2-3/4 Master Wall® pails, filled). Using a clean mixer, first add 1/2 to 2/3 the water required, 1/2 the sand, 1 bag Cemplaster Fiberstucco, then the rest of the sand and water to achieve the desired workability. Mix materials for 3 to 5 minutes after all materials are in the mixer. Total water content can vary between 4 to 6.5 gallons (15-24.5L). Stucco Ad-Liquid may also be used instead of an equal amount of water (up to 5 gallons, 18.9L). See system data sheet for specific levels required for increased warranties.

Tempering—The mixed stucco can be re-tempered one time within 1 hour. Material older than 1-1/2 hours should be discarded.

Scratch Coat: apply Cemplaster Fiberstucco with sufficient pressure to key into and embed the metal lath (if used). Apply sufficient material, approximately half the Cemplaster Fiberstucco ground thickness to cover the metal lath and to permit scoring the surface. Score the Cemplaster Fiberstucco horizontally upon completion of each panel in preparation for brown coat if a “double back” application of a wet scratch and brown coat isn’t being used.

Brown Coat: as soon as the scratch coat is firm enough to receive the brown coat without damage, apply the brown coat with sufficient pressure to ensure intimate contact with the first coat to an approximate thickness as needed to bring the Cemplaster Fiberstucco to a uniform thickness that matches the grounds of the accessories. Use a rod or straight edge to bring the surface to a true, even plane. Fill depressions in plane with Cemplaster Fiberstucco.

After the Cemplaster Fiberstucco has become slightly firm float the surface lightly with a Darby or wood float to densify the surface and to provide a smooth, even surface.

Moist cure using fogging, plastic films or other method acceptable to the design professional for 48-72 hours. Mixes with Master Wall® Stucco Ad Liquid do not need moist curing.
Allow to fully cure until clean, dry and hard before finishing:

•Typically 7-14 days if no Master Wall® Stucco Ad Liquid is used.
•After 72 hours if Master Wall® Stucco Ad Liquid is used provided the Cemplaster Fiberstucco is clean, dry and hard.
•After 24 hours if using a leveling base coat (LBC).

Clean Up—Tools and equipment can be cleaned with soapy water while the Cemplaster Fiberstucco mixture is still wet.

If sanding or scraping are performed, ventilate work area and/or use a NIOSH/MSHA-approved respirator in accordance with our Safety Data Sheet.

Information contained in this product data sheet conforms to the standard detail recommendations and specifications for the installation of Master Wall Inc.® products and is presented in good faith. Master Wall Inc.® assumes no liability, expressed or implied as to the architecture, engineering, or workmanship of any project. This information may be concurrent with, or superseded by other applicable documents, such as specifications and details. Contact Master Wall Inc.® for the most current product information. ©2018 Master Wall Inc.®