Effect of machined profile, zinc oxide and titanium dioxide particles on checking southern pine deck boards during weathering

Abstract

The aim of this research was to test the hypothesis that the combination of profiling, treatment and a surface coating with nanoparticles will be effective at reducing checking in deck boards exposed to the weather. In this study southern pine (Pinus sp.) deck boards were machined to flat (control) and ribbed surface profiles. The specimens were treated with aqueous copper amine azole (CA-C) using a vacuum/pressure method and coated with nano-ZnO and micronised TiO2. Boards were exposed to accelerated weathering for 576 h. The number, length and width of checks that developed in the boards were quantified and the average amounts of cupping, twist and bowing occurring in the weathered wood were examined. The results of the statistical analysis showed that all of the coated ribbed decking samples had lower average check numbers, lengths and widths compared to the end-matched flat untreated specimens. Checks were also shorter and narrower in the profiled southern pine deck board than in the unprofiled specimens. Furthermore, the lowest amount of cupping, twist and bowing were observed for specimens profiled and coated with the TiO2. Therefore, the authors conclude that the coated ribbed decks looked significantly better than the flat decking.

Manufacture of Profiled Amabilis Fir Deckboards with Reduced Susceptibility to Surface Checking

“…Despite this trend, profiling has only been tested on a handful of North American species including southern pine, blue-stained lodgepole pine (Pinus contorta Dougl. ), subalpine fir (Abies lasiocarpa (Hooker) Nuttall), and white spruce (Picea glauca (Moench) Voss) [12][13][14][15][16][17][18]. Furthermore, the testing that has been carried out has used a limited number of profiles.…”

“…The checking of wooden decking can be reduced by adding hydrophobes (wax and/or oil) to the chemical preservatives that are used to treat the decking [8,9], or by applying a water-repellent stain to deckboards [10]. An alternative approach to reducing the checking of deckboards that is attracting increasing attention in North America is to machine small ridges (peaks) and grooves into the surface of boards [11][12][13][14][15][16][17][18]. The dimensions of The H/W ratios of profile peaks are comparable between each of the three profile types ( Figure 1).…”

Digital Image Correlation of Strains at Profiled Wood Surfaces Exposed to Wetting and Drying

“…Profiling makes the surface of wood less slippery [5], and it also reduces the negative effects of weathering checks on the appearance of decking [7]. Recently, there has been interest in North America in optimizing surface profiling to make it more effective at reducing the checking of wooden deck boards made from different species [7][8][9][10][11][12][13][14]. Such interest in profiling stems from the desire to create wooden decking that can match the performance of wood plastic composites, or manufacture decking from species whose susceptibility to surface checking has been an obstacle to their successful exploitation for deck boards [9,15].…”

Optimizing Surface Micro Grooving to Reduce the Checking and Cupping of Douglas Fir, Western Hemlock and White Spruce Decking Exposed to Natural Weathering

“…They are not common in North America. Interest in manufacturing profiled wooden deckboards in North America is increasing, but profiling has only been tested on a handful of wood species [12][13][14][15][16][17][18][19]. Previous results suggested that rib profiles with narrow grooves were better than profiles with wider grooves (ribble or ripple profiles) at reducing the checking of amabilis fir [19], but studies have also shown that the effectiveness of different profiles varies with wood species, as mentioned in the introduction [13,15].…”

“…As a result of the success of wood plastic decking, there has been significant interest in improving the resistance of wooden deckboards to weathering and in particular checking. This interest explains the recent attention in North America to optimizing profiling to make it better at reducing the checking of deckboards exposed to the weather [12][13][14][15][16][17][18][19]. It also accounts for increasing interest in Europe and elsewhere in deckboards made from tropical wood species or thermally or chemically modified woods that are less susceptible to checking and cupping than preservative-treated deckboards [20][21][22].…”