This study tests the hypothesis that ‘the ability of surface profiling to reduce checking of deck boards exposed to weathering will vary with wood species and profile type’. Southern pine (Pinus sp.) and Pacific silver fir (Abies amabilis) deck boards were machined to produce three different types of surface profiles: flat (control), ribbed (V-shaped grooves), and rippled (U-shaped grooves). Boards were exposed to accelerated weathering for 5 days, and the number and sizes of checks that developed in boards were quantified. Surface profiling reduced the total number and total width of checks in both Pacific silver fir and southern pine deck board specimens, but it had a greater effect at reducing checking in Pacific silver fir than in southern pine. The ribbed profile, in particular, was much more effective at reducing checking of Pacific silver fir than it was at reducing the checking of southern pine. Therefore, we conclude that the effectiveness of surface profiling at reducing checking of deck boards depends on wood species and the type of profile machined into wood surfaces. Checks developed in the grooves between the ribs of profiled boards and appeared to be constrained from becoming wider to a greater extent than becoming longer. Therefore, we conclude that the beneficial effect of profiling on the appearance of boards arises because checks are much narrower than those on flat boards and are located in the grooves, where they are difficult to see.

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