Plastic Composite Lumber

by Christi Graham

What is it?

Imagine stepping barefoot onto what appears to be a redwood deck in 100 degree weather and yet your feet are comfortable. No splinters, no slipping, no warping - all this because you happen to be standing on plastic lumber. This composite material is used to produce building products such as decking, door and window frames, and exterior moldings. Treated lumber, which is most frequently used for decking is often considered hazardous and must be disposed as hazardous waste making plastic lumber a very desirable alternative. Additionally, since plastic lumber is impervious to the elements (e.g., wind, water, sun, insects and salt air) - the typical enemies of wood, it can be used for many residential and even commercial applications. So go ahead, use plastic lumber and starve a termite!

There are essentially two types of recycled plastic lumber: plastic and recycled wood/composite plastic lumber. Both are molded or continuously extruded into standard lumber forms.

Plastic Lumber

100% plastic lumber can be made with recovered plastics such as HDPE, PET or several commingled recovered plastics. The HDPE raw material comes from post-consumer waste (primarily milk jugs) and PET comes primarily from post-consumer soda bottles.

Composite Plastic Lumber

Recycled wood/ composite plastic lumber is made from a 50/50 mix of plastic resins and reclaimed wood such as sawdust from manufacturing plants that would otherwise be discarded. Plastic composite lumber is one of the prime uses for recycled plastic trash bags and waste wood fibers. Manufacturers claim that recycled wood / composite plastic lumber is more rigid than 100 percent recycled plastic lumber because the wood fibers act as reinforcement. In addition, the plastic encapsulates and binds the wood to resist moisture penetration and degradation from fungal rot, bringing together some of the best properties of both wood and plastic.

Overview of benefits:

• Uses recycled materials (no virgin wood, no virgin plastic)
• Can be recycled after use
• Decreases the amount of plastic in the landfill
• Reduces replacement costs
• Does not contain toxins (e.g. copper, chromium and arsenic) found in treated wood
• Does not require painting, sealing, waterproofing, staining, treatment or maintenance
• Does not absorb moisture and is not slippery when wet
• Is more flexible than wood
• Does not splinter, crack, rot or warp

Uses

Applications include low load structural (applications) such as decks, floors, marine docks, piers, fences, railings, playgrounds, landscape timbers, lawn and garden products, patio furniture, porch columns and picnic tables. Commercial applications include: parking stops, railroad ties, trash and recycling receptacles.

Attributes

Health

Plastic lumber has minimal impact on personal health since it does not contain any preservatives or chemical additives found in treated lumber. Being maintenance free keeps homeowners away from inhaling noxious fumes when applying treatments that would otherwise be required.

Environmental

Plastic lumber has minimal environmental impact since it keeps material out of the waste stream and incinerators and can be recycled again at the end of it's useful lifetime. An estimated 12% of the U.S. solid waste stream is plastic, and of that 19% is high-density polyethylene (HDPE). More than 750 recycled milk jugs and detergent bottles are used to make a single four foot long plastic bench - thus providing an end use for materials already in the waste stream.

It does not leach toxic chemicals into the soil or water

Minimizes wood use. Wood is the most extensively used building material. The average house contains about 13,000 board feet of framing lumber. In ideal circumstances wood would be a renewable resource, yet given present logging techniques and growing demand , it is not. Replacing virgin wood with plastic lumber is a more sustainable alternative.

Functional Characteristics

Features

You can purchase plastic lumber decking materials in a wide range of colors, and textures to complement any home's exterior.

Installation

Plastic lumber can be installed using common carpentry tools and will cut, drill and rout very cleanly because there is no grain to split or chip. Both screws and nails with a hot-dipped galvanized coating are acceptable fasteners. Again, because there is no grain, pre-drilling is not required for self drilling screws. Pneumatic nailers also work well with this material.

Plastic lumber should not be used as a structural component (e.g. support post, joist, or stringer) unless it has been engineered for a specific application.

For most residential applications, plastic lumber will require joist spacing similar to traditional lumber. When using 5/4" x 6, or 2" x 6" decking boards, the joist spacing should be 16" on center. However, two plastic lumber products (Boardwalk and Weather Best) are engineered for a longer span - up to 24" on center.

Maintenance

None required! It can be sanded down to remove scratches or washed to remove stains

Performance / Durability

Most recycled plastic lumber is ultraviolet light (UV) stabilized to resist sunlight damage. Plastic lumber manufacturers offer a limited lifetime guarantee and will replace any pieces that crack, warp or break.

Considerations

Be aware that not all plastic lumber is made from recycled materials, so it is important to request recycled content.

Plastic lumber can loose it's strength characteristics at temperatures of 160 degrees F and above.

Plastic lumber expands and contracts more than wood and is heavier than dry wood of the same size.

Could cause irritation to people who are sensitive to fiberglass if a fiberglass composite plastic lumber is used.

Who Makes It

Plastic Lumber

Carefree - by Vandermeer Forest Products. This decking system consists of decking, rail caps, spindles, and bull-nose stair treads made of 100% post-consumer HDPE.

EcoDeck - distributed by Environmental Building Products. EcoDeck is made from 100% recycled plastic, has a wood grained appearance and is available in two colors.

Polywood - by Polywood Inc. is made from 100% recycled plastic in a variety of colors

Composite Plastic Lumber

E-wood - by McPharlan Cascade resembles redwood or cedar in color and has a "grain" pattern all the way through. E-wood comes with it's own clips and railing system.

Next wood - by TimberTech is a 100% recycled HDPE and cellulose fiber composite decking product. Currently, rice hulls are used instead of wood fiber.

Boardwalk - by Certain Teed

Smart Deck - by SmartDeck Systems is made from a patented composite of fine oak sawdust from post-indistrial sources and recycled HDPE. Smart Deck is a complete decking system including rails, trim, fascia and posts.

Choice deck - by AERT, Inc is a decking product composed of 48% recycled plastic and 52% recycled wood fibers. The color is dark brown when installed and weathers to a silver gray color in 4 to 6 months.

Weatherbest - by Louisiana Pacific

Trex - by Trex Co, LLT is probably one of the better known manufacturers of plastic lumber. Available in Natural, Winchester Grey and Brown.

Forever Deck - by Phoenix Recycled Plastics

For current contact information for manufacturers and distributors of plastic lumber, please visit georgebeeler.com.

Cost Factors

Comparable in price to high grade cedar or low grade redwood.

Notes

The "Impact-Post" support post (by XPotential products, Inc.) is a plastic composite product manufactured with 100% recycled materials made from post consumer and post industrial plastics such as car parts. This post has been used successfully in conjunction with plastic lumber fencing.

Other places we suggest you look (or - for further information)

Plastic Lumber Trade Association
540 South Main Street, Building 7
Akron, OH 44311
800-886-8990

References

ADPSR West Coast Architectural Resource Guide - David Kibbey. Ed. / Architects/Designers/Planners for Social Responsibility - Northern California Chapter, Berkeley, CA - revised 9/29/1999

Environmental Building News. Vol. 7:7-7

The Partnership for Advancing Technology in Housing (PATH) - Technology Inventory Document

Trex LLC. promotional literature

Residential Environmental Design Newsletter, March - April 2001 Issue

Solid Waste Management Coordinating Board, Environmentally Preferable Purchasing Guide. 4/2000 - Section 8.1

Joint Service Pollution Prevention Opportunity Handbook, complied for the Navy, Marines, Air-force & Army, Section 7- Solid waste Management