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The evaluation of a survey of dry rot damages in Japan
1983 - IRG/WP 1179
The damage of wooden houses from Serpula lacrymans has increased in Japan, particularly in the northern area, Hokkaido Prefecture (See Figure 1). The weather conditions in Asahikawa have been recorded. The data obtained from the survey carried out over the five years from 1975 to 1980 were previously reported to the 5th International Biodeterioration Symposium which was held in Aberdeen, Scotland in 1981. This paper deals with the evaluation of the survey which has been extended to 7 years to 1982, and which was restricted to Asahikawa. The position of the occurrence of dry rot was inferred from the extent of the decay and/or the hyphal activity.
S Doi


A field test on susceptibility of wood-based board materials to moulds
1989 - IRG/WP 3545
A field test on susceptibility of wood-based board materials to mould growth was carried out under practical, but severe, service-conditions. A total of 19 commercially available composite boards were investigated. It was found that all board materials tested were not completely immune to mould attack. Test results revealed that among the three main categories of wood-based boards involved, particleboards were the most susceptible, followed by fiberboards. Plywoods were less susceptible to mould growth. The test also showed that among various types of board materials, the asphalted fiberboard, the particleboards made from birch wood shavings, and wood-industry residues were the most vulnerable to mould growth.
Qiao Wang, B Henningsson


The effect of different foundation systems against fungal flora in the crawl space of a new wooden Japanese house
2009 - IRG/WP 09-10700
In order to establish novel preventive measures against damage of wooden houses by decay fungi with less-use or no-use of chemicals, we periodically monitored the fungal flora in the crawl space of a new wooden Japanese house build with recyclable and low-environmental load materials at the Research Institute for Sustainable Humanosphere, Kyoto University. We employed either a layer of concrete or just soil as the foundation system of the crawl space of the model Japanese house. Moisture content of Sugi foundation timbers and temperature & humidity of the crawl space with different foundation systems were measured as well as the sampling of fungi by the following methods: a) from the crawl space atmosphere with a PDA plate, b) from foundation timbers with a soft transparent plastic tape, and c) from small wood blocks laid on a layer of concrete or on soil. Fungi, which were visually estimated to be basidiomycetes, were also identified with DNA-based methods. Then a monoculture decay test was conducted with these fungi. Numbers of fungal colonies grown from the concrete foundation samples were significantly lower than those from the soil foundation samples. Over the year the soil section generally showed higher humidity and moisture content than the concrete section. These findings suggested that the soil strongly influenced the water condition of the crawl space, indicating the higher decay risk in the soil section than in the concrete section. Most of isolated basidiomycetes were white rot fungi with the exception of a brown rot fungus, Fomitopsis pincola. The majority of the white rot fungi were Trametes vesicolor. In order to analyze effect of soil on the fungal flora, all ventilation slits were air-tightly closed with aluminium tape for each crawl space section after all the sampling was completed. This resulted in higher colony forming unites (CFUs), humidity and moisture content of foundation timbers. This study clearly indicated the close relationship between the risk of wood decay and the foundation system in wooden Japanese houses, and the higher decay risk in the soil section than in the concrete section.
A Toyoumi, S Horisawa, T Yoshimura, S Doi,Y Imamura


Mould growth on wood-based materials – a simulated in-service study
2012 - IRG/WP 12-20503
Ten different wood-based materials including preservative-treated wood, fire retardant-treated wood, modified wood, WPCs and untreated references of pine sapwood and spruce were placed in three different environments (an attic and two crawl spaces) for a period of 26 months. Mould growth was analysed at five to seven month intervals in an effort to map the growth development. The relative humidity and temperature were logged continuously. The results obtained from testing in the two crawl spaces generally corresponded well with a previous laboratory study. None of the materials tested could completely withstand mould growth during the 26 months’ exposure time. Most promising results were obtained with the preservative-treated WPC and the least promising with the modified wood materials. For the latter, poor mould resistance is of major concern.
G Bok, P Johansson, J Jermer


Experimental real building evaluation of termite attack - Effect of the space between the mat foundation and the thermal insulation
2000 - IRG/WP 00-10374
For evaluating the termite resistance of the real house foundation, specially in the case of thermal insulation systems for foundation walls, thermal insulation which can be attacked by termite, must be evaluate. Because of the difficulty of the water penetration of thermal insulation, the water barrier systems can be protected against termite attacks, in our opinions. The observation on the process of the penetration by termites and ones of a traditional barrier system against termites were evaluate by the real building scale test method.
K Suzuki, K Hagio, Y Tanaka


The density factor in termite bioassays
1985 - IRG/WP 1252
The initial and final floor surface and food block surface actually used by termites in a small container were converted to estimates of "Living Space" and "Feeding Space" densities for 1/32 to 1½ g groups of termites. The termites were provided with blocks of blotter paper as a food supply. Except where 1½ g groups exhausted the food, the survival of termites was uniformly high (averaging >96%). The growth, block weight loss, debris production and feeding rates declined progressively as densities increased; however, these rates stabilized where 1/2, 1 and 1½ g groups had equalized feeding densities. This stabilization demonstrated that feeding space density, but not living space density, affected the termite performance. The advantage and disadvantage of using a matrix in termite bioassays is discussed.
G R Esenther