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Composite Decking

Durable exterior decking material that needs no maintenance and doesn't crack, split, or warp

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A new decking material is available that needs no maintenance and doesn't crack, split, or warp. The exceptionally durable exterior decking material is made from fiberglass reinforced plastic (FRP) Installing FRP decking materials.that is both attractive and is expected to last the life of the home without routine maintenance. Traditional wood decking materials, both preservative-treated and naturally rot-resistant materials, have a life expectancy ranging from 10 to 20 years when maintained periodically with chemical sealants. FRP decking is stronger and more durable than traditional decking, and retains an attractive appearance without maintenance.

This new decking material is made of pultruded fiberglass reinforced plastic. Pultrusion is a process in which continuous strands of fiberglass are pulled through a bath of polyester resins to coat the fibers, and then through a die to give the desired profile. FRP materials are strong enough to be used as structural beams in industrial applications that require resistance to chemical attack and fire. The material is also highly scratch and impact resistant and is colored throughout, which allows it to retain its looks with only periodic washing.

FRP decking is typically sold as an entire system, including deck boards, attachment clips, trim, and hand rail material. The decking material is typically attached to a standard preservative-treated wood sub-frame. Deck profiles are "C" shaped, sized comparable to 2 x 4 and 2 x 6 lumber, and can be run at 45 or 90 degree angles to the support joists. Edge trim is used to cover lumber support framing and hide the hollow profiles of the deck boards. Handrail assemblies are also available that include include handrail, bottom rail, and spindles. Optionally, systems can accommodate the installation of an integrated bench.

The initial cost of FRP decking is significantly higher than conventional alternatives, despite its overall long-term value. Decks should be designed so that full-width planks are used (planks cannot be cut to narrower widths, like wood, to fill in small gaps). Otherwise, gaps will be left between planks. Preservative-treated wood structural framing lasts considerably longer when sheltered by the FRP deckboards, but it may be less durable than the FRP decking and rail material.

Quality and Durability

As an engineered material, FRP decking is consistent and not subject to warping, splintering, or cracking. FRP decking is extremely durable and virtually maintenance-free.

Safety and Disaster Mitigation

FRP decking does not cause splinters.


FRP decking systems are available through retailers nationwide, or from local decking contractors trained to install this type of decking.

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Manufacturers of FRP decking systems have listings with U.S. model building code agencies and will provide documentation of the system's performance to help obtain local approval.

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FRP decking systems are designed to allow easy installation for do-it-yourselfers using standard carpentry tools. First, the deck's support framing, consisting of wood joists, is constructed. Maximum spacing of joists is 24 inches when decking runs perpendicular to framing. FRP deck boards are pre-cut to the length needed, up to 40 feet. Retaining clips are then mounted to the framing, and the FRP deck boards are "snapped" into place. The hollow ends of decking boards are covered by trim. Handrail components are pre-routered to simplify layout and installation.

FRP decking systems can be installed in new construction, or they can be attached to existing deck substructure after removing deteriorated deckboards and rails. There are numerous decking contractors that are trained to install FRP decking systems. Retailers, however, will provide both product and design specifications for self-installers.

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Advantages of FRP decking material center on its durability and maintenance-free operation. Traditional decking materials require frequent washing and sealing to maintain looks and durability. A manufacturer of FRP decking states that it is nearly three times stronger than wood and nine times stronger than vinyl decking. FRP decking is more scratch and dent resistant than other decking materials and it does not stain or mildew. Few chemicals can harm the appearance of FRP decking and scratches can be removed by buffing.

Because FRP decking does not shrink and expand as do other decking materials, unsightly gaps are not required between joints and seams. It has no exposed fasteners to mar the finished appearance. Unlike unreinforced plastics, it permanently holds it shape; it does not crack, split, or warp; and it does not become brittle in the cold, or soft in the sun.

FRP decking systems are more costly than standard decking options. Despite the higher cost, they are cost-competitive with other materials because they are expected to last the life of the home. The installed cost of FRP decks is about double that of decks constructed with preservative treated wood, and about 50 percent more than redwood and cedar decks.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.