20th November, 2019

Different Types of Recycled Plastic Lumber

Nature can batter relentlessly at structures and frames big and small. Rain pours, insects drill, and invisible microorganisms eat away at the wood we rely on so heavily. That doesn’t even take into consideration the wear and tear people cause. At the same time, when wood structures fall apart, we just replace it with more wood, which consumes a lot of resources. What can we do to remedy this? One viable answer is to use recycled plastic wood instead. Plastic lumber saves waste materials from dump sites and boasts more longevity and resilience than real wood. Plastic lumber also comes in many effective variations to fit a plethora of needs. These are the different types of recycled plastic lumber in production today.

High-Density Polyethylene Recycled Plastic Lumber

This is plastic lumber in its purest form, as it’s comprised almost entirely of homogeneous plastic. High-density polyethylene (HDPE) is the primary substance in this type, comprising up to 95 percent of the lumber. HDPE is the same material used for milk jugs, refillable plastic water bottles, and some plastic bags, which plastic lumber manufacturers recycle to make plastic wood.

HDPE plastic lumber is suitable for a range of small-scale applications, including outdoor furniture pieces, playground equipment, fencing, and pallet decks. Manufacturers can make it in a wide variety of colors as well as change the surface texture to more closely mimic wood.

Compared to traditional timber, HDPE plastic lumber better resists weather, rot, deterioration, and insect borers. This significantly diminishes the long-term need for maintenance, meaning you can spend less time and money on keeping it in a usable and visually appealing condition. Without added materials, however, this type of plastic wood is softer compared to other forms, which is why it’s only used for smaller applications.

Wood-Filled Recycled Plastic Lumber

The composition of wood-filled plastic lumber includes a mixture of polyethylene plastic and fine recycled wood fibers (e.g. sawdust). This actually contributes to the recycling of both plastic and wood waste that would normally go to a landfill. Much like HDPE plastic lumber, wood-filled plastic lumber is often used in decking, fencing, house siding, window and door frames, and indoor and outdoor furniture. In addition, it has been employed in the making of toys for children and dogs because of its nontoxic coloring and lack of splinters.

The properties and appearance of wood-filled recycled plastic lumber can be changed depending on the ratio of plastic to wood, what type of wood is used, and how large the wood particles are. A higher plastic-to-wood ratio increases flexibility so that the lumber can be bent into curved shapes, which is impossible to attain with normal wood. Higher wood content makes the melting point of the material lower, since wood can burn, but it also results in a more rigid product. The strengths of this type of plastic lumber include greater traction due to its rougher texture and its lack of voids (empty spaces). However, the inclusion of natural wood does make it susceptible to some of the same problems that normal timber experiences. Most notable among these is its tendency to soak up and hold moisture.

The remaining two variation factors are primarily aesthetic. For example, hardwood can make the lumber darker in color, while pine will make it lighter. Furthermore, larger wood particles contribute to a more organic appearance than small particles.

Commingled Recycled Plastic Lumber

In some cases, the plastic that recycling companies accept is actually a blend of different substances, which facilities can recover and transform into a functional material known as commingled recycled plastic lumber. The requirement for this kind of plastic lumber is that the plastic is about 80 to 90 percent polyethylene.

Allowing for this amalgam of plastics means that the possibilities of commingled plastic lumber’s production are expanded, while the costs associated with sorting through recyclables are reduced. Moreover, the plastic utilized is usually waste that wouldn’t be usable in any other situation, even within the plastic industry. The downside is that the mixed nature of its composition causes it to have a low strength-to-weight ratio, causing it to expand, soften, and become hot to the touch in high temperatures. This is because the molecular bonds that exist in normal plastic—which can be recreated in more homogeneous recycled plastic resins—do not form as readily in commingled plastic.

Nevertheless, commingled plastic lumber has been successfully implemented in a number of nonstructural roles, including fencing, landscape timbers, compost receptacles, and parking blocks. To make up for its weaknesses, innovators have melded it with HDPE, allowing it to be used in the construction of picnic tables and outdoor benches.

Fiber-Reinforced Recycled Plastic Lumber

Of the four categories, fiber-reinforced recycled plastic lumber is the stiffest, as it contains chopped and continuous glass strands. This quality allows it to excel in large structural and support applications that the other varieties cannot sustain. Within this type of plastic lumber, there are a couple subtypes that are specialized for different settings.

The first of these subtypes is fiber-reinforced plastic lumber comprised of glass fibers alone. Everything from walkways and decks to retaining walls and marinas can be constructed with this material.

Another form of this type of plastic lumber includes glass fiber-reinforced polymer rebar, which is thicker than fiberglass strands. Its high durability lends it to use in substantial structures that must bear heavy weight burdens and endure considerable kinetic force, such as pedestrian and utility bridges. Marinegrade lumber also has rebar reinforcement, allowing it to be used in many coastal buildings. Fender piles are a good example of its application, as they can withstand the pushing of boats and the movements of the water.

Available in several earth tones, fiber-reinforced plastic lumber can still resemble wood. In rustic or natural settings such as forests, lakes, and beaches, this type can blend in with the surroundings to make for a pleasing aesthetic. Conversely, it can also smoothly blend into industrial settings, as it comes in monochrome grays as well. Unlike those made of wood, structures built with this type of plastic lumber don’t degrade when they’re exposed to water, dirt, and organisms, so their strength and integrity endures over time.

Whatever your project and specific requirements, Tangent has the right plastic lumber for you, so feel free to give us a call.

Recycled Plastic Lumber