Top 7 Composite Decking FAQs

Considering a new Fiberon composite deck? Chances are you have some questions. Read on to find answers to some of the most common decking questions.

1.    What’s the difference between capped and uncapped composite decking?

Composite decking has always provided clear advantages over pressure-treated wood decking. Early versions of composite decking, however, were uncapped, so they lacked a protective top layer to provide true stain and fade resistance. Consequently, some of these products developed mold, faded from continual UV exposure, and/or were prone to staining. All of that changed with the introduction of capped composite decking.

Fiberon Symmetry Decking in Cinnabar looks like premium hard wood and keeps that natural look, thanks to its PermaTech cap layer.

Capped composite decking has a protective outer layer that is co-extruded to the wood-composite core during the manufacturing process. It is fused to the board, so there is no need to worry about the cap separating from the core. Fiberon developed and trademarked its cap layer, a product we call PermaTech®. This unique cap layer contains color additives, UV inhibitors, biocides, and other ingredients to ensure your decking retains its rich, natural wood appearance without the concerns of fading, staining, mold, or mildew. Plus, when you consider that Fiberon composite decking never needs sanding, staining, or refinishing, it’s easy to understand why more and more homeowners are making the smart move from wood decking to composite decking.

 2.    What’s the difference between grooved and non-grooved deck boards?

Use Fiberon grooved edge boards and hidden fasteners for a smooth, indoor-quality flooring surface.

Grooved deck boards have channels that run the length of the board on both sides. These channels enable the boards to be installed using hidden deck fasteners. First, the fastener (sometimes called a deck clip) is placed into the groove. Then, to secure the clip, a screw is driven into the joist either at an angle for metal fasteners or at 90 degrees for plastic fasteners. The board is then snapped into place, and the process is repeated on the other side.

Non-grooved deck boards (also called square-edge boards) are solid on all sides. They are installed using either Fiberon Cortex hidden face fasteners or 2.5-inch #8 composite deck screws. In both instances, the fastener is screwed straight down into the board. For the Cortex hidden fasteners, a color-matched plug is then inserted over the screw to minimize the hardware’s appearance.

3.   Can grooved deck boards be used for stair treads?

No, we do not recommend using grooved deck boards for stair treads for two reasons. First, the groove will be facing out and will not be aesthetically pleasing. Second (and most important), the long-term performance of the board may be compromised. Here’s why: When someone is walking up a staircase, the bulk of his/her weight is distributed across the front of each step. This is where the groove is located; therefore, over time, the groove could crack from the continual weight bearing down on it. We recommend using only square edge deck boards for stair treads.

4.  Can Fiberon Decking be used as a substructure?

Fiberon composite decking has many outstanding qualities; however, it is simply too flexible for use as a structural component of the deck. Of course, anytime you are installing Fiberon decking, always follow all installation guidelines and local building codes.

Fiberon Horizon Decking in Ipe adds plenty of dramatic appeal, but should never be used as a substructure.
5.    Can Fiberon Decking be installed over existing joists and framing?

Yes, Fiberon Decking can be installed over an existing substructure if the following conditions are met:

  • The existing framework must be free of any damage or decay and in good, workable condition (consider having the space assessed by a licensed deck inspector).
  • The joists must be spaced correctly.
  • There must be adequate cross ventilation and unobstructed airflow under 50% of the deck. Allow a minimum of 1.5 inches (4 cm) between bottom of joist and the ground. Water must be able to flow away from under the deck. Improve drainage or grade flat areas where standing water may gather, and do not install decking directly to an existing or solid surface.
6.    How much space is needed between deck boards for proper drainage and ventilation?

Allow a minimum of 3/16 inch. between Fiberon composite boards (side to side) to ensure proper drainage and ventilation and to assist with the removal of small organic debris. Allow a minimum of 1/4 inch. spacing between boards and any permanent structure. Spacing is a requirement to ensure full Fiberon warranty coverage.

Correct board spacing is essential to ensure adequate space for normal expansion and contraction. Shown here: Fiberon Symmetry Decking in Warm Sienna.

Depending on the weather and temperature conditions on installation day, the amount of normal expansion and contraction of the boards will vary. Darker colors will naturally expand more than lighter colors, in much the same way that darker objects heat up more in the sun than lighter ones. However, to help control end-to-end spacing, all decking should be kept at ambient temperature and shaded from direct sun prior to cutting and installing.



7.    How do I clean clogged spaces between by deck boards?

If the gap between decking boards is less than 3/16 inch (4.8 mm), organic debris such as leaves, seeds, or pollen can settle on the deck and clog gaps. Water can pool, steeping organic debris. This will result in a “tea” or tannin which could stain your decking. Standing water could also cause the boards to swell, resulting in cracking, warping, and cupping of the material. If the gapping becomes clogged, use a garden hose, spatula, putty knife, or similar tool to remove the debris, taking care not to gouge or scratch the deck boards.

Consult Fiberon decking and railing FAQs when you need more information. Or contact our helpful Customer Service team at 1-800-573-8841.



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