Environmentally friendly decking

by Sally Bouorm | December 1, 2010 2:45 pm

By Brent Gwatney

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Demand for wood-plastic composite lumber is projected to increase 9.2 per cent in each of the coming years, reaching $5.3 billion US by 2013, says a recent study by The Freedonia Group. It also predicts deck boards will be the leading application.

Composites have become a popular choice for decking around swimming pools and spas, as well as many other residential and commercial applications, due to their splinter-free, slip-resistant surface, and the ability of some brands to resist moisture. These characteristics—combined with durability, an attractive appearance and increasingly appealing environmental traits—have made composites one of the fastest-growing segments in the decking market.

As demand continues to increase, the number of manufacturers and the variety of brands available in the market has grown. To help select environmentally friendly composite decking products and ensure design goals and expectations are met, builders and designers should consider the following characteristics.

Recycled, or not

With more than 40 manufacturers, all wood-plastic composite decking is not created equal. Most are made with a combination of polyethylene (PE) plastic, wood fibre and a variety of additives, which help stabilize the plastic, enhance colour and protect the decking from ultraviolet (UV) damage, mould and mildew. However, despite using the same or similar ingredients, each manufacturer has its own product formulation and processing technologies.

The use of recycled content, for example, is not universal. Some manufacturers use only virgin materials, while those that incorporate recycled content vary greatly in the amounts used. Some manufacturers claim their products include recycled material, but often omit the details on the overall percentage and specific amounts of pre- and post-consumer content. It is important to keep this in mind and find out the actual percentages. The amount can range from zero to approximately 95 per cent (additives and colour agents are typically included, preventing decking from being considered 100 per cent recycled content).

In addition to verifying percentages, determining whether the recycled materials come from pre-consumer or post-consumer channels will also help in selecting the most environmentally friendly product. Pre-consumer materials are generated by manufacturers and processors and may consist of scrap, trimmings and saw dust. Post-consumer material is waste that has been used and disposed of by consumers and diverted from landfills (e.g. detergent containers, milk jugs, plastic bags or film).

Post-consumer waste is harder to obtain and recycle, thus it is more likely to end up in a landfill. For these reasons, composite decking containing post-consumer recycled content is considered to be more environmentally friendly. Composite decking with a substantial percentage of post-consumer content can even help contribute toward green building rating points in Leadership in Energy and Environmental Design (LEED) programs.

For additional information on a product’s environmental background and the manufacturer’s commitment to being ‘green,’ visit their website or read through product literature to understand their processing practices and what they are doing as a company to minimize their impact on the environment. If a company is doing what it claims, there should be information to support their ‘green’ claims. Researching brands will also help determine the history and track record of their products.

Made to last

Differences in manufacturing processes also lead to variations in performance characteristics. The plastic in composite decking products serves as the binding agent, while the wood fibres add stiffness, reduce flammability and help simulate the look of natural wood. Most commonly, manufacturers mix wood fibres with plastic and then heat and extrude the material into deck boards. Each manufacturer has its own process; therefore, each product differs in makeup and appearance.

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The plastic is what protects the wood fibre from moisture, so its ability to surround and bond to the wood fibres during the manufacturing process can significantly impact the long-term integrity of the decking. Should wood fibres become exposed over time, the deck boards can absorb moisture and be susceptible to mould, mildew, discolouration and, in some cases, decay.

To prevent this from happening, some manufacturers use a total encapsulation method wherein wood fibres are aligned and completely enclosed by plastic. The finished product absorbs substantially less moisture than other composites and solid wood, and has greater rot and insect resistance. Composite deck planks manufactured in this manner can be used in applications where direct contact with the ground (landscape trim) or water (pool and spa surrounds) is necessary; otherwise it must be elevated to avoid direct contact.

Compared to all-plastic decking, composite products provide lower thermal expansion, further supporting the material’s performance in harsh environments. For example, in variable climates, wood-plastic composites may be more suitable for decking than plastic materials, as the latter tend to expand and contract more with temperature changes.

Composite materials also resist splintering, twisting, splitting and cracking, which makes the material suitable for children’s play equipment, access ramps, outdoor showers and in recreational facilities, where safety is a concern. Its firm, non-slick surface holds up well to heavy foot traffic, and under typical conditions, composite decking is expected to last two to three times longer than traditional decking materials.

Residential and commercial warranties vary and can range in coverage from five years to lifetime. Read through warranties carefully to determine what the manufacturer covers and to ensure there are no surprises down the road.

Appearance matters

Due to advancements in technology, manufacturers can now fabricate composite deck boards that mimic the appearance of real wood. Depending on the manufacturer, they are available in many textures, colours and profiles.

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Colour choices range from grey to warm, multi-dimensional hues, allowing builders and designers to complement existing structures and mix and match multiple colours to create unique layouts. The most popular composite deck boards tend to have deeply embossed, realistic-looking wood grain textures emulating the look of tropical hardwoods.

To ensure a decking product will meet desired esthetic and performance goals, it is important the customer is able to see and feel a sample before making a final decision. When selecting materials, keep in mind most decking typically weathers to a slightly lighter shade within the first six months of installation, depending on exposure.

Composite deck boards are available in solid, hollow or ribbed profiles and with or without grooved sides for hidden fastening systems. Solid planks are the most similar to sawn-lumber in appearance and handling, while hollow composites are generally lighter, do not bend as easily as solid boards and require trim or end caps.

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When heated, composite deck planks can be bent for use in such applications as curved stairs, trellis and walkway arches and any surface or non-structural element that calls for round edges.

Decorative railing accessories, including posts, post caps, balusters and trim boards, are also available in some composite decking product lines. Railing accessories can incorporate convenient details, such as hollow posts for easy installation of outdoor lighting, security systems and audio equipment. Railing materials can also be shaped or curved during installation to add visual interest.

Another option builders and designers have are composite deck tiles. They offer a durable, versatile and environmentally conscious outdoor surfacing option for exterior spaces and are quick and easy to install on virtually any hard, level surface (e.g. concrete, gravel, an existing deck, etc.) to enhance its appearance. Composite deck tiles are often used on concrete decks surrounding pools. Similar to composite decking, they resist rot, moisture and insects, and are sometimes made with recycled content.

Code considerations and installation

In addition to environmental attributes, performance and appearance, code approval is an important factor to consider when selecting decking products. To be approved under the International Residential Code (IRC) and International Building Code (IBC), for example, a composite decking product must have an International Code Council (ICC) Evaluation Service (ICC-ES) report, confirming it has passed a series of tests outlined in the ICC-ES document AC174, Acceptance Criteria for Deck Board Span Ratings and Guardrail Systems (Guards and Handrails) (June 1, 2009).

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The tests evaluate a product’s structural properties, durability and surface-burning characteristics, including span, fastener holding ability, elasticity, bending strength, ultraviolet (UV) and freeze-thaw resistance, fire performance, termite resistance and the effects of temperature, moisture and fungal decay. To find out if a product is code-approved, check the manufacturer’s website or the ICC-ES website (www.icc-es.org). If approved, the product packaging should include its code listing.

Understanding building code regulations and substructure requirements for spans is essential with composite decking. Typically, composite deck boards require a 406-mm (16-in.) on-centre joist span for installation and 305-mm (12-in.) span for diagonal installation. Composite decking follows underlying support surfaces more closely than wood planks do, so it is important to ensure joists are level with one another to avoid a wavy surface appearance.

Like solid lumber, composite decking materials are easily machined, and can be installed with standard hand and power tools. Since composite boards have no grain, there is no risk of splitting. To attach composite boards to underlying structural members, builders can use nails, screws or hidden fastening systems. For some composite decking products, stainless-steel trim head screws can minimize the chance for metal corrosion or staining on the material. However, not all composite decking products are compatible with each attachment method, so it is important to follow manufacturer recommendations.

Engineered, long-lasting beauty

Composite decking and railing offers an engineered option for builders and landscape professionals seeking a durable, environmentally sound alternative to conventional building materials. And, with a little research to ensure the material chosen meets the performance and design goals for a project, it can offer enduring strength and beauty for many years.

ECO-FRIENDLY CARE AND CLEANING

All decking requires maintenance for long-lasting beauty and durability; composite products are no exception. Manufacturers typically recommend periodic cleaning—sweeping to remove dirt and debris, and if necessary, a soft bristle scrub brush with mild soap and warm water to gently remove spots. Pressure washers can also be used to clean composite decking. Maximum pressure amounts can differ depending on the manufacturer. To avoid damage to the deck boards, a pressure washer typically should be set at less than 90 kgf/cm2 (1,280 psi) and have a fan tip blade that is held at least 203 to 254 mm (8 to 10 in.) away from the surface. For tannin stains (e.g. from plants, coffee, tea and wine) or stubborn spots, cleaners containing oxalic acid (C2O4H2), commonly known as deck ‘brighteners,’ can be used to remove them. In some cases, difficult-to-remove stains or spots may require multiple applications. Cleaners should always be tested in an inconspicuous area of the deck before full application, to ensure the desired results. Most conventional composite deck cleaners contain sodium hypochlorite (NaOCl), which can help prevent and fight mould and mildew. Any cleaner containing bleach may lighten the decking surface and should be used in accordance with the manufacturer’s instructions. Plants and shrubs around a deck should be sprayed with water before and after the use of cleaning solutions. Oxygen-based bleach cleaners, often referred to as oxygenated bleach, provide an environmentally conscious alternative to chlorine-based bleach. Cleaning alternatives that do not contain bleach, ammonia (NH3) or volatile organic compounds (VOCs) are also available.

 

Brent Gwatney is vice-president of sales and marketing for MoistureShield, a composite decking materials manufacturer in Springdale, Ark. He can be reached at bgwatney@aert.cc[6].

Source URL: https://www.poolspamarketing.com/trade/environmentally-friendly-decking/

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