Plastic wood is a term used broadly in home improvement to describe a wood alternative offering enhanced durability and weather resistance. This material refers to two distinct categories: structural lumber used for building and a putty-like compound used for repairs. The structural material, often called Wood-Plastic Composite (WPC) or plastic lumber, is designed to replace traditional timber in outdoor construction projects. The second type is a solvent-based wood filler used to patch and restore existing wooden items.
Understanding Plastic Wood Materials
The structural form of plastic wood is a hybrid material known as Wood-Plastic Composite (WPC), combining the aesthetic of wood with the resilience of plastic. WPC is manufactured by blending fine wood fibers or wood flour with heated thermoplastic resins, such as polyethylene (PE), polypropylene (PP), or polyvinyl chloride (PVC). Additives are included to ensure the wood fibers bond effectively with the plastic polymers, improving the final product’s dimensional stability and moisture resistance.
Plastic lumber, a related product, is made entirely from recycled plastic, often high-density polyethylene (HDPE), without wood fibers. Both WPC and plastic lumber are valued for their resistance to rot, moisture absorption, and insect damage, common issues with natural wood. These properties result in a low-maintenance material that does not require regular staining or sealing.
The second material referred to as plastic wood is a high-performance, solvent-based wood filler or putty used for restoration and repair. This compound contains wood fibers mixed with resins that cure into a hard, durable surface. Unlike water-based fillers, the solvent-based formulation is designed for heavier-duty repairs and exhibits superior resistance to shrinking and moisture once cured.
Major Outdoor Construction Uses
The most widespread application for structural plastic wood is in the construction of outdoor living spaces, where its moisture resistance provides a significant advantage. Decking and railing systems represent the largest market segment, as the material resists the warping, splintering, and decay common to traditional wood decks. The composite boards maintain a consistent appearance and offer a splinter-free surface, making them safer and more comfortable.
Fencing is another major use, particularly for privacy fences and structural posts constantly exposed to the elements. Using plastic wood eliminates the need for periodic painting or staining, significantly reducing the long-term maintenance burden. The material’s resistance to termites and fungal growth ensures the fence posts remain structurally sound, even when in direct contact with the ground.
Plastic wood is also frequently used to construct outdoor furniture, including park benches, picnic tables, and chairs. The material’s durability against rain, sun, and temperature fluctuations ensures the furniture will not rot or degrade. This longevity makes it a preferred choice for public spaces and residential areas where furniture must withstand heavy use and minimal upkeep.
Specialty and Repair Applications
Beyond large-scale construction, the structural composite material is well-suited for landscaping projects where ground contact is unavoidable. Raised garden beds and retaining walls benefit from the material’s inability to absorb moisture, preventing the rot and decay that quickly affect treated timber. The composite’s stability ensures that these structures maintain their form and integrity for decades.
The material is also used for exterior trim and siding, particularly around windows and doors where water exposure is high. Using plastic wood for cladding and trim helps seal the building envelope against moisture intrusion and eliminates the need for frequent repainting. Its ability to be molded into various profiles allows it to mimic the look of traditional millwork while offering superior weather performance.
The putty-like “plastic wood” filler is specifically used for repairing existing wooden items, both indoors and outdoors. This solvent-based compound is applied to fill deep cracks, gouges, and holes in furniture, trim, and flooring. Once cured, the filler hardens to a density similar to real wood, allowing it to be sanded, drilled, or planed for heavy-duty restoration tasks.
Key Differences from Natural Wood
A primary benefit of choosing plastic wood over natural lumber is its exceptional longevity and low maintenance profile. The composite material can last 25 to 30 years without requiring the staining, sealing, or painting that traditional wood demands. This reduced upkeep translates into savings in time and money over the lifespan of the installation.
The environmental aspect is another consideration, as many plastic wood products are manufactured using recycled wood fibers and recycled plastics, diverting waste from landfills. However, the initial purchase price for plastic wood is often higher than that of conventional lumber.
Plastic wood also behaves differently under temperature extremes compared to natural wood. While it resists moisture-related warping, the material is sensitive to heat and can exhibit greater thermal expansion and contraction than timber. Although manufacturers have improved the aesthetics, the appearance of plastic wood may not fully replicate the unique grain patterns and natural character of real wood.