PVC fence designs are becoming more elaborate. They developed in the early 1990s from simple posts and slats into complex interlocking systems with tongue-and-groove "privacy panels" and a variety of molded finials and caps.



The big design news at January's Fence Tech 2000 show in Tampa, Fla., was a 1.5 x 13.4 in. tongue-in-groove privacy panel with eight internal support ribs, which Outdoor Advantage says is the widest fence profile on the market.

Cap layers are blooming with new colors in the past six months. Whereas fences have typically been either white, tan, or gray, Kroy recently added khaki, navy blue, forest green, burgundy, and "Timberlast" woodgrain (made by striping black ink into a monolayer tan or gray profile). Bufftech introduced a marbleized woodgrain effect two years ago.

Most processors of fence profiles are evaluating foam as a way to raise output and possibly gain other attributes like sound deadening. Foam is used in PVC building profiles, but these tend to be light trim pieces, not free-standing ones, because foam reduces PVC's impact strength, though it can increase stiffness.

Reedy International Corp., Keyport, N.J., recently introduced Safoam RIC-FP chemical blowing agent for PVC. It's said to have the smallest particle size on the market-7 microns vs. 35 microns for previous products. Reedy sources note that foaming increases throughput by 10-20% because CO2 generated by the blowing agent in the extruder acts as a lubricant or processing aid.

The next wave of fence developments is likely to include wood -composites. Wood-filled PVC and polyolefin rails, with and without cap layers, are already commercial, though they are heavier and more expensive than conventional PVC fences. Cap layers give a painted look, but the composites can also be embossed or finished to look like natural woodgrain.

Adding wood flour is a natural progression for current PVC fence makers, because of the greater heat resistance of wood composites. "Hypothetically a wood composite should do better in hot climates," says Al England, v.p. of Strandex Corp., Madison, Wis., which licenses proprietary wood-composite profile technology that is now widely used for decks and rails.

Meanwhile, makers of wood-composite "plastic lumber" for other applications are being drawn to the fence market which include such as temporary fence,wire mesh,fence manufacturers,steel fence post,wire fence,portable fence etc. One of these is Comptrusion Corp. in Toronto, a three-year-old maker of wood-filled PVC decking, railing and window profiles. Says v.p. Jim Pratt, "Our initial market analysis was that it would be a stretch for composites to compete with pressure-treated wood fences. But we can compete with plain PVC. I'm glad the PVC fence growth curve is going off the charts, because it will stop people from comparing the cost of plastic alternative fences to wood." Comptrusion plans to expand production next year in Canada and the U.S. "We'll be going after the fence market once we get a handle on the volume for the rails and decks-probably next year," Pratt says. "We'll look at performance-rated fences like acoustical fence first, which is something PVC alone can't do."

Trex Co. in Winchester, Va., which makes nonstructural plastic-lumber decking and slats out of waste wood fibers and reclaimed PE grocery sacks and stretch wrap, also is producing fence slats. "Fencing is a growing application for us and an excellent use for nonstructural components like vertical pickets and slats," says sales and marketing manager Andy Ferrari.

Louisiana Pacific Corp. in Portland, Ore., set up its first wood-composite decking plant at ABT Co. in Selma, Ala., last month. "The next logical extension is fencing," says product development manager Scott Sackinger.

Equipment suppliers have started to tailor products for wood-composite profiles. ESI Extrusion Services Inc. in Akron, Ohio, recently delivered its first downstream finishing chamber for wood-filled polyethylene deck and rail profiles. It has rotating brushes that create surface grooves resembling woodgrain. Fences could be its next application. ESI has also developed an in-line routing and cut-off system for standard plastic or wood-composite fence posts. Up to now, post holes for railings have been cut off-line with CNC routers.

As an example of how PVC fencing operations are growing, Bufftech in Buffalo, N.Y., had one PVC fence profile plant when the company was bought by Certainteed in 1996. Certainteed has since converted one of its own pipe plants in McPherson, Kan., to fence extrusion and is adding fence capacity at another Certainteed plant in Social Circle, Ga. In five years, Irwin Industries, Peachtree City, Ga., has expanded its PVC fence capacity from zero to 18 coextrusion lines, or 36 extruders. Twenty extruders were added in just the past six months.