• Sina Heshmati Department of Wood Science, University of British Columbia, Vancouver, BC, Canada
  • Lukie H Leung Department of Wood Science, University of British Columbia, Vancouver, BC, Canada
  • Mohammad Sadegh Mazloomi Department of Wood Science, University of British Columbia, Vancouver, BC, Canada
  • Joseph Doh Wook Kim
  • Philip David Evans Department of Wood Science, University of British Columbia, Vancouver, BC, Canada


Douglas fir, western hemlock, white spruce, treated decking, profiling, checking, cupping, growth ring orientations, weathering


Machining grooves into the upper surface of wooden deckboards reduces undesirable checking that develops when deckboards are exposed to weather. But profiled boards cup more than unprofiled boards. We sought a solution to this problem and hypothesized that profiling both sides of boards would reduce the cupping of profiled boards. We tested the effects of profile type (Flat, single-, and double-sided profiles) and growth ring orientation (concave vs convex) on the cupping and checking of alkaline copper quaternary-treated deckboards made from Douglas fir, western hemlock, and white spruce. There were significant differences in the cupping of deckboards made from the three different wood species (Douglas fir<white spruce<western hemlock), and boards with concave growth ring orientations cupped significantly less than boards with convex growth ring orientations. Most importantly, our results show that double-sided profiling reduces the cupping of deckboards, irrespective of wood species, and growth ring orientations of deckboards. Double-sided profiling also significantly reduced checking of deckboards exposed to the weather. We conclude that profiling the underside or profiled deckboards to create a “balance” double-sided board is a simple solution to the problem of increased cupping that develops when profiled (single-sided) softwood deckboards are exposed to weather.


Akhtari M, Nicholas D (2014a) Effect of profiling and preservative treatments on the weathering characteristics of southern pine deck boards. Eur J Wood Wood Prod 72(6):829-831.

Akhtari M, Nicholas D (2014b) Effect of machined profile, zinc oxide and titanium dioxide particles on checking southern pine deck boards during weathering. IET Nanobiotechnol 9(3):103-106.

Anon (2019) Get in the groove. Introducing profiled decking. The newest innovation in preserved wood outdoor products. (17September 2019).

Bailey WC (1944) Balanced striated plywood panel. U.S. Patent 2,363,927.

Bottcher P (1977) Influence of different surface profiles on weather resistance of wood. Holz als Roh Werkst 35(7):247-251 [in German].

Cheng KJ, Evans PD (2016) A note on the surface topography of profiled wood decking. Aust For J 79(2):147-152.

Cheng KJ, Evans PD (2018) Manufacture of profiled amabilis fir deckboards with reduced susceptibility to surface checking. J Manuf Mater Process 2(1):7.

Christy AG, Senden TJ, Evans PD (2005) Automated measurement of checks at wood surfaces. Measurement 37(2):109-118.

Englund F (2010) Durability by design of wooden cladding and decking–An overview of guidelines and information

sources. Rep 38 SP Tratek, Stockholm, Sweden. 30 pp.

Evans PD, Cullis I, Morris PI (2010) Checking of profiled southern pine and amabilis fir deck boards. Forest Prod J 60(6):501-507.

Evans PD, Urban K, Chowdhury MJ (2008) Surface checking of wood is increased by photodegradation caused by ultraviolet and visible light. Wood Sci Technol 42(3): 251-265.

Freedonia Group (2020) Wood and competitive decking—Demand and sales forecasts, market share, market size, market leaders. Competitive-Decking.html (11 March 2020).

Heshmati S, Mazloomi MS, Evans PD (2018) Optimizing surface micro grooving to reduce the checking and cupping of Douglas fir, western hemlock and white spruce decking exposed to natural weathering. J Manuf Mater Process 2(4):67.

Holmes N (2018) The effect of depth of ribbed profiles on strain concentrations in white spruce boards during accelerated weathering. B. Eng. thesis, The Australian National University, Canberra, Australia.

Kavanaugh C (2019) Composite decking making market gains. Plastics News, July. (11 March2020).

Koehler A (1929) Raised grain—Its causes and prevention. So Lumberman 137:210M-210O.

Kuhne H, Leukens U, Sell J,Walchli O (1970) Investigations on weathered wood surfaces. I. Scanning-electron-microscope observations on mould fungi causing grey stain. Holz als Roh Werkst 28(6):223-229 [in German].

Mallet J, Kalyanasundaram S, Evans PD (2018) Digital image correlation of strains at profiled wood surfaces exposed to wetting and drying. J Imag 4(2):38.

Marsh G (2009) Marinas—Low-tech prospect for useful returns? Reinforc Plast 53(1):30-33.

McFarling SM, Morris PI (2005) High performance wood decking. Pages 99-109 in Proc. Canadian Wood Preservers’Association, October 25-26, Toronto, Canada.

McFarling SM, Morris PI, Knudson RM (2009) Extracting greater value from subalpine fir: Profiled decking. Forest Prod J 59(3):24-28.

Morris PI, Ingram JK (2002) Field testing of wood preservatives in Canada. XI. Nine-year inspection of the CITW decking test. Pages 156-169 in Proc. Canadian Wood Pres. Assoc. Conf., October 22-23, Vancouver, Canada.

Morris PI, McFarling S (2008) Field testing of wood products in Canada XVII: High-performance profiled wood decking. Pages 72-82 in Proc. Canadian Wood Pres. Assoc. Conf., October 28-29, Vancouver, Canada.

Nejad M, Cooper P (2011) Exterior wood coatings. Part-1: Performance of semitransparent stains on preservative treated wood. J Coat Technol Res 8(4):449-458.

Nystrom R (1995) Board for use in constructing a flooring surface. U.S. Patent 5,474,831.

Ratu R, Weizenegger J, Evans PD (2007) Preliminary observations of the effect of kerfing on the surface checking and warping of flat sawn southern pine decking. Proc. Int. Res. Group Wood Protection Meet, May 20-24, Jackson Lake Lodge, WY, IRG/WP 07-20360.

Schniewind AP (1963) Mechanism of check formation. Forest Prod J 13(11):475-480.

Urban K, Evans PD (2005) Preliminary observations on the effect of growth ring orientation on the surface checking of flat sawn southern pine decking. Proc. Int. Res. Group Wood Protection Meet. April 24-28, Bangalore, IRG/WP/05-20313.

Williams S, Knaebe M (1995) The bark side/pith side debate. The Finish Line. USDA For Serv Forest Products Laboratory, Madison, WI. 2 pp.

Williams LJ, Herve A (2010) Fisher’s least significant difference (LSD) test. Page 6 in N Salkind, ed. Encyclopedia of research design. SAGE, Thousand Oaks, CA.

Yata S (2001) Occurrence of drying checks in softwood during outdoor exposure. Pages 65-70 in Y Imamura, ed. High-performance utilization of wood for outdoor uses, Wood Research Institute, Kyoto University, Kyoto, Japan.





Technical Notes