Wood materials in outdoor use are exposed to conditions that may be favorable to decay fungi. Glulam beams are used in numerous large structures since the 1960s onwards. One would expect similar conditions and similar decay patterns in all large-dimension wood materials in the same exposure, but our investigations show different patterns in solid wood logs and glulam beams. Decay damages in glulam beams exposed outdoors often affect single lamellae in the beams, and typical decay fungi are Gloeophyllum sepiarium, Dacrymyces stillatus and Ditiola radicata. Different wood protection and surface treatments cause various growth conditions, resulting in characteristic distributions of decay within the beams. In solid wood logs exposed outdoors, damages often occur in large cracks or underneath an intact surface layer. Antrodia species, Gloeophyllum sepiarium, Coniophora puteana and Leucogyrophana mollis are common degrading agents in solid wood logs. In this paper three glulam damage cases are discussed in order to pinpoint typical properties of decay damages in glulam beams as compared to solid wood logs. Possible explanations for the differences are discussed. The growth conditions on exposed surfaces and in cracks seem to be of large importance.
Keywords: glulam beams, solid wood beams, decay fungi, fungal decay, growth conditions, decay patterns
Authors
Austigard M.S.
Mycoteam AS, Oslo, Norway
Jenssen K. M
Mattsson J.
Login to download the PDF