6 Wood Discoloration

8.5 Damage to Structural Timber Indoors 233
staining with fluorescein diacetate is suitable (Huckfeldt et al. 2000; also Koch
et al. 1989; Bjurman 1994).
The possibilities to identify S. lacrymans cover the classical methods of fruit
body investigation (Grosser 1985; Pegler 1991), strand diagnosis (Falck 1912;
Table 2.4, Appendix 1), and mycelium analysis by identification key (Stalpers
1978). As modern techniques, protein polyacrylamide gel electrophoresis
(Schmidt and Kebernik 1989; Vigrow et al. 1989; Palfreyman et al. 1991;
Fig. 2.19) and immunological tests (Palfreyman et al. 1988; Vigrow et al. 1991c;
Toft 1992, 1993; Glancy and Palfreyman 1993) were tested for suitability. DNA
techniques have been established (Schmidt 2000) and are already used commercially.
MALDI-TOF mass spectrometry was capable of differentiating the
mycelium of the True dry rot fungus and its closest relative the Wild merulius
(Schmidt and Kallow 2005; Fig. 2.24). Measurement of microbial volatile organic
compounds (MVOCs) may identify wood-decay fungi (Bjurman 1992b).
Pinenes, acrolein, and ketones were found in Serpula lacrymans, Coniophora
puteana, and Oligoporus placenta (Korpi et al. 1999). Mono- and sesquiterpenes,
aliphatic alcohols, aldehydes and ketones, and some aromatic compounds
were emitted by Fomitopsis pinicola, Piptoporus betulinus, and further
species (Rosecke et al. 2000). Blei et al. (2005) showed that MVOC analysis
was able to distinguish pure cultures of Antrodia sinuosa, C. puteana, Donkioporia
expansa, Gloeophyllum sepiarium, S. lacrymans, and S. himantioides.
Field experiments, however, were influenced by the distance of sampling from
the infested and/or destroyed wood and also by the rates of air changes.
To improve the technique of MVOC analysis, Keller et al. (2005) measured
volatile compounds in non-infested living and bedrooms as a background
reference for infestation. Trained sniffer dogs can also detect S. lacrymans
(Koch 1991).
If S. lacrymans is proven, the fungus is (beside longhorn beetle and termites)
the only biological damage causer for which there is the obligation in
some German states (Hamburg, Hessen, Sachsen, Thüringen, and Saarland)
to become registered. Since costs of refurbishment can be considerable (to
e3,000 per m 2 living space), the determination of the extent of the damage and
theremedialtreatmentsshouldbedonebyarenownedcompany.InGermany,
refurbishment has to follow the standard DIN 68800 part 4. In the case of a lawsuit,
§459 of the German Civil Code regarding “regress for material defects”
takes effect.
8.5.4
Prevention of Indoor Decay Fungi and Refurbishment of Buildings
All decaying fungi need water for wood decay. Elimination of the source of
moisture and drying of wood and masonry after prolonged wetting are the
www.taq.ir