Composite deck makers combat slippery boards

TORONTO (May 6, 1 p.m. ET) -- Slipperiness is one of the biggest complaints consumers have for wood composite decks, according to a speaker at the 11th International Conference on Biocomposites in Toronto.

Consumers can slip on wood plastic composite decks and injure themselves. Ironically, composites tend to be slippier when dry than when wet, according to Anatole Klyosov, principal of Mir International Inc. of Newton, Mass.

“WPC is slippier than wood,” Klyosov told delegates.

He suggested wood plastic composite board manufacturers use a wire brush to finish the surface of their products, provide deep embossing or change the plastic in the matrix to one not so slippery.

Klyosov listed several other problem areas that cause complaints among consumers. These problems have led to five lawsuits against wood plastic composite manufacturers and suppliers from 2004 to 2010.

Rotting and splintering can occur after a manufacturer claims the product is maintenance free. In an unnamed case in New Jersey, a manufacturer had to pay $1.8 million in costs and attorney fees after a complaint. The manufacturer had to replace the product and discontinue its claim of being maintenance free.

Oxidative degradation leads to problems like crumbling or cracking that can be corrected by adding sufficient antioxidant compounds. In one case an Ohio lumber company spent more than $8 million to cover damages and a product recall for its composite deck boards. Defects were alleged to oxidative degradation. Some metal pigments and additives can also induce crumbling.

Excessive moisture content can lead to mold and mildew formation. Wood plastic composite materials typically have moisture content of 0.7 to 3 percent, but if the board is porous it can hold much more water in the interior of the board. Claims of moisture resistance and low maintenance don’t hold if porosity is excessive.

“Porosity can hold water,” Klyosov said. “Minimize porosity by minimizing water content.”

Porosity control can also be achieved by not exceeding desired processing temperature or line speed.

Shrinkage can occur if the manufacturing line is too fast or if cooling occurs too suddenly after manufacturing. Shrinkage of up to 0.5 percent is possible and can be a particular problem for hollow boards.

“Provide time to cool, relax and shrink the board at the manufacturing site,” Klyosov told attendees.

Photo oxidation and fading can occur with excessive amounts of regrind or lack of inorganic pigments.

Other potential problems include strength issues, deflection, thermal expansion and contraction, termite resistance and flammability.

(You need to be approved by the site owner before your comment will appear. Until then, it won't appear on the entry. Thanks for waiting.)

Fields marked with * are required.