In Norway log buildings are normally produced from logs canted on two sides. The canted faces are prone to crack formation during drying. This can cause some disadvantages, e.g. the cracks can trap water from rainfall, because the canted faces form the wall surfaces in the log buildings. The objective of the reported study was to apply saw kerfs on the upper side of the cants prior to drying to reduce crack formation in the canted faces. The material consisted of 150 mm wide cants produced from Scots pine (Pinus sylvestris) logs with a mean top-end diameter under bark of 23 cm. Immediately after canting the cants were divided into four groups: A Chain saw kerf to pith, B Circular saw kerf (9 cm deep), C Circular saw kerf (4.5 cm deep), D Untreated control. The timber was air dried and stored under roof for 4 years. Widths of cracks in the side faces were measured. The results showed that mean crack width was reduced by 60 % by applying chain saw kerf (treatment A). The two other treatments had limited effect on crack formation in the side faces.
Keywords: Log building timber, kerfing, crack formation, Scots pine
Authors
Flæte, P.O.
Norwegian Institute of Wood Technology, Oslo, Norway
Larnøy, E.
Norwegian Forest and Landscape Institute, Ås, Norway
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