Demand for wood-plastic composite and plastic lumber will climb 10% a year through 2011 to $5.4 billion worldwide, forecast the Freedonia Group.

Driving demand will be the materials' durability, weatherability, low maintenance requirements, low life-cycle cost, increasing consumer and contractor familiarity, a widening distribution network, aesthetic product improvements, and ongoing interest in green building materials.

Plastic lumber has found significant use in agricultural fencing, molding and trim, and is pushing into decking, fencing and end uses such as site and leisure furniture. 

Composites, however, will enjoy faster growth through 2011, posting gains of 14.3% annually to reach $2.6 billion. Biggest growth will come in decking, window/door components, and niche end uses (porches, site and leisure furniture). 

By 2011, decking will be the largest end use for composites and plastics, accounting for 44% of demand. Molding and trim will remain a key market, but with below-average growth due to increasing market maturity and a weak new housing environment. Plastic fencing gains will also be limited.