Effects of center boring and kerf treatment on kiln-drying of larch square and round timbers

yThe applicability of improving kiln-drying and qualities of manufactured structural larch timbers with large cross section was examined. Beneficial results of kiln-drying center-bored larch timbers included uniformity of internal moisture content (MC), with final shell to core gradient averages being reduced from 10.4 to 1.0 percent, and a generally substantial reduction in the number and overall length and width of drying checks, which increased value and beauty, without reduction in such mechanical properties as bearing capacity and parallel-to-grain compression strength. The overall length of checking in kerfed timbers was reduced 9 to 92 percent, averaging 55 percent. Final MC of the center-bored timbers averaged 7 percent lower than the solid timbers with the equivalent drying time of the first two kiln runs, and were dried to 15 percent MC target in half the time in the third kiln run. Additional benefits include the expectation that the rapid drying rate and lowered weight will make construction work with center-bored timbers more convenient, and the low and uniform internal MC profile will reduce the possibility of shape distortion after installation.