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Test method for assessing resistance of pine lumber and waferboard to mold

Year:

2005

Publication type:

Miscellaneous Publication

Primary Station(s):

Forest Products Laboratory

Source:

Forest products journal. Vol. 55, no. 12 (Dec. 2005): pages 164-166.

Description

Methods are needed to evaluate the ability of framing lumber and composite construction materials to withstand mold growth when they are exposed to rain between manufacture and installation. A laboratory-controlled rain chamber was developed to expose biocide-treated specimens of pine lumber and waferboard to bi-weekly wetting followed by re-inoculation with test fungi. In the rain chamber mold test, an experimental biocide, which contained propiconazole, performed as well as the positive control, which contained iodo carbamate and didecyl dimethyl ammonium chloride. However, results from the rain chamber test method did not correlate with results from a standard ASTM laboratory mold test for the experimental biocide. In additional tests of kiln-dried, rewetted, and unseasoned pine, untreated specimens showed heavy mold growth after 7 days regardless of their original moisture content. Results for a matching set of specimens dip-treated in disodium octaborate tetrahydrate (DOT) revealed that rewetted and unseasoned specimens supported mold growth equally well after a 4-week incubation in the laboratory mold test, while DOT-treated kiln-dried specimens moderately inhibited mold growth. These specimens likely retained more treatment than did their wet counterparts. Ideally, waferboard and kiln-dried pine should be rewetted to adequately support mold growth in the standard laboratory mold test. The rain chamber mold test provided prolonged conditions of high moisture, even for kiln-dried pine and waferboard specimens, and mimicked exposure of construction materials to moisture during storage.

Citation

Clausen, Carol A.; West, Michael. 2005. Test method for assessing resistance of pine lumber and waferboard to mold. Forest products journal. Vol. 55, no. 12 (Dec. 2005): pages 164-166.

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https://www.fs.usda.gov/treesearch/pubs/22101