Overview

U-STUCCO™ XPX has been independently tested in accordance with ASTM G21-13, Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi. This rigorous evaluation assesses how materials perform when continuously exposed to fungal organisms under controlled high-humidity and temperature conditions.

Test Methodology

Procedure:

ASTM G21-13, Sections 9.1–9.3 (observation for visible fungal growth).

Duration:

28 days of incubation at 28–30 °C (82–86 °F) and 85%+ relative humidity.

Samples:

Three U-STUCCO™ specimens and three control specimens were inoculated with a composite spore suspension and incubated.

Fungal Cultures Used:

Aspergillus brasiliensis (ATCC 9642)

Penicillium pinophilum (ATCC 11797)

Chaetomium globosum (ATCC 6205)

Trichoderma virens (ATCC 9645)

Aureobasidium pullulans (ATCC 15233)

Results

According to ASTM G21 rating criteria (0 = no growth, 4 = heavy growth):

U-STUCCO™ XPX specimens:

Rated 0 (no visible fungal growth).

Control specimens:

Rated 4 (heavy growth, full coverage).

Key Takeaway

U-STUCCO™ XPX demonstrated complete resistance to fungal growth under ASTM G21 testing. This means our material is highly resistant to mold and mildew even in high-moisture, humid environments—making it ideal for coastal regions, humid climates, and long-term durability in all building assemblies.

Why It Matters

Ensures healthier indoor environments by preventing mold and mildew formation.

Reduces long-term maintenance and repair costs.

Provides additional value in LEED and green building certifications.

Validates U-STUCCO™ as a superior alternative to traditional stuccos and coatings.