Composite and structural plastic lumber are manufactured using a wide range of formulations, primarily for use in decking, railing, trim, and structural applications. These materials are engineered to offer durability, aesthetic appeal, and in some cases, structural strength depending on their composition.
Types of Composite Lumber
Wood Composites
Among the most common are wood-plastic composites, such as Timbertech, Trex, and Fiberon. These products typically contain 40–50% polyethylene (often from reclaimed grocery bags or stretch film) and 50–60% wood fiber from recycled pallets or furniture manufacturing byproducts. These composites are valued for their attractive finishes and broad warranty coverage, generally ranging from 5 to 25 years, with some extending up to 50 years for protection against fading, staining, mold, mildew, and structural integrity issues.
Polystyrene and PVC-Based Composites
Another category includes PVC and polystyrene formulations, such as Azek products. These contain no wood fiber and are commonly used for exterior trim, decking, and railing. They are offered in a wide selection of colors and finishes and are typically not suited for structural applications.
Plastic Lumber Formulations
HDPE and LDPE-Based Plastic Lumber
Plastic lumber can also be made from various recycled materials such as milk jugs, grocery bags, shrink wrap, and even car bumpers. These materials are usually processed into high-density polyethylene (HDPE) or low-density polyethylene (LDPE) lumber.
To improve product performance, plastic lumber formulations often include:
- Anti-foaming agents – to reduce internal voids
- Ultraviolet (UV) inhibitors – to protect against sunlight degradation and maintain color stability
- Additives like fiberglass or minerals – to enhance flexural strength and reduce thermal expansion and contraction
Structural Applications and Durability
Structural Use
Structural plastic lumber can be specifically engineered for demanding applications including posts, beams, joists, girders, piers, boardwalks, and railings. Unlike many wood or PVC composites, it is suitable for use in structural settings and can be installed in soil, rock, concrete, or even saltwater without voiding warranty coverage.
Durability and Warranty
Plastic lumber is highly resistant to splintering, cracking, mold, and insect damage. Most products offer limited warranties of up to 50 years for residential, commercial, and structural uses.
Final Considerations
Note: The information above is general in nature. Due to ongoing innovations, consumers should verify specific product formulations and warranties directly with manufacturers, as these may evolve over time.
We do require pre-payment prior to processing. We do not accept credit cards at this time.
Signed estimates are required as part of our operations processing, essential for order verification and to ensure order accuracy. Thank you for your understanding. We very much appreciate your business.
To turn your estimate into an order, the process is simple:
- Send your Approved and SIGNED estimate
- All orders are custom and must be prepaid. Payment is accepted via the following methods:
- Check (send scanned/photocopy of your check prior to mailing to expedite) or
- Wire transfer (send proof of wire transfer transaction to expedite) or
- Direct deposit, Wells Fargo Bank (send proof of ACH to expedite)
Should you wish to send payment via bank deposit or wire, our accounting department will send you the information and instructions.
Nearly all purchases are special order and custom; not stock items held in inventory.
At American Plastic Lumber, we do our best to ensure you are quoted the appropriate product and satisfied with your purchase, however: All sales are final. Orders cancelled after placement, during production or post-production require management’s review and may be subject to a 50% Restocking Fee for lumber or sheet goods and 60% on furniture or unassembled products. Please check your item(s) as soon as they arrive and contact us in writing immediately if order is incorrect or damaged, with notice of damage noted on freight bill before signing for delivery. Photos of damaged goods is required.
All returns or cancellations are subject to approval and require a Return Authorization (RA) number in advance. Return shipping costs are the responsibility of the purchaser unless damages occurred in transit.
Our plastic lumber is less rigid than wood and as such may require more support and/or possibly a larger size or structural grade material. Because of the higher rate of expansion and contraction it may be recommended that the material be pre- drilled with a slotted hole to allow the material to move and prevent fasteners from breaking. We recommend high quality stainless steel screws and fasteners. Stainless screws are most commonly recommended.
It is recommended that an engineer review the design prior to installation in order to comply with technical specifications provided, relative to the expansion and contraction characteristics of the material(s), as well as the fastening method(s) used.
Recommendations for Installation:
- Pre-drill and oversize all holes in order to allow for the expansion and contraction of the material.
- Use good quality stainless steel or galvanized hardware.
- Do not over tighten the hardware–the material has to be able to move.
The beauty of plastic lumber is its “maintenance-free factor”. Since it is impervious to stains and does not absorb water/moisture, grease/oil or any liquid for that matter, the product requires little maintenance other than perhaps an occasional washing with soap and water.
ADDITIONAL CLEANING INFO
Cleaning may be done with a power washer, taking caution to ensure nozzle does not get too close to lumber or using a brush with a mild soap/cleanser and water.
Various types of plastic lumber are available on the market today, and they differ in numerous aspects. Some are molded and some are extruded, producing different surface textures. Most are made from high density polyethylene, (HDPE) some low density polyethylene (LDPE) and some from polypropylene (PP) or a combination. The plastic is heated then blended with additives such as ultra-violet light inhibitors, colorant, foaming agent, anti-static compound, chopped fiberglass, or even solid fiberglass bars, as may be required for heavy load applications. The materials may be *recycled to some extent containing postindustrial and or post-consumer and sometimes virgin plastic. This allows them to fall into a composite type product category, however what separates them from other “composite” products is that typically PLASTIC LUMBER contains no wood fillers, or mineral by-products and as a result it carries a much longer warranty, up to 50 YEARS. Further, the structural plastic lumber materials can be utilized for engineered girders, beams, joist and posts, unlike the wood composites with the short term warranties!
Lead times vary from a few days to numerous weeks depending upon the product profile, color, and quantity. An estimated lead time can be given when a material estimate is provided, however subject to change until order is scheduled into production.
While the initial cost to purchase recycled plastic lumber can run 2-3 times that of standard wood materials, it becomes considerably less expensive long-term when you factor in the maintenance cost avoidance plus removal and replacement labor. Plastic lumber carries A manufactures limited warranty against mold, termites, fungal decay, and will not split or splinter up to 50 years.
Friction is reduced in frost or snow conditions, or with oil spillage much like standard wood, steel or concrete, however plastic lumber is less slippery wet than dry. The material has a paraffin-like base and similarly, surfboards that are waxed so surfers can stand on them in the water, our plastic boards become tacky when they are wet. Numerous wood grain and industrial textured surfaces are also an option for added traction.
Since our recycled plastic boards do not absorb water, chemicals, oil etc. they do not absorb paint or glue, however there are brand name products that have some history of success.
Standard woodworking tools are used to cut, drill, or router the plastic boards and sheets including pneumatic nail guns and CNC routers. Material with fiberglass rods requires carbide tipped blades. Screws and nails are retained up to 30 percent better than in standard wood materials.
*See installation guidelines and span charts
Additional information available upon request
The plastic boards are not porous so they will not absorb stains or water. This makes them able to resist salt, gas, oil and water. Because they will not absorb water, they will not grow mold, rot, crack, split or warp. Occasional cleaning with a light detergent or power washing is recommended annually.
Plastic lumber is less rigid than wood, has a higher rate of expansion and contraction and performs well in even the most extreme weather conditions, however it is not a direct replacement for wood. Prior to installation, allow the product to adjust to the existing temperature, particularly if the material was stored for some time at a different temperature or sun exposure.
When pre-drilling, oversize holes in order to allow for expansion and contraction, allow gaps at each board end in cold installations. Expansion and contraction must be taken into consideration in the design stage to avoid installation issues over time.
*Please see our technical data page