Technical Information

Usage Guidelines

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Trex® Decking and Railing is suitable for a wide range of applications. Trex is not intended for primary structural members such as load bearing columns, joists, stringers and beams. In most installations, a span of 16” on center using a minimum of 3 joists will provide excellent results. Please refer to the Trex Decking and Railing Span Chart for specific requirements or consult the Trex building code listings (International Code Council Evaluation Service ESR-1190) or the Trex evaluation reports (Canadian Construction Materials Centre – CCMC 13125-R).

IMPORTANT: Trex decking must always be installed properly gapped and directly on joists. Do not attach Trex decking to any solid surface or water tight system such as sheathing, waterproof membranes, concrete, roof systems, or patios.

• Getting Started
• Handling and Storing
• Cutting and Drilling
• Fastening
• Gapping
• Decking, Railing & Stair Span Charts
• Cleaning
• Colors
• Weathering Process
• General Construction Facts

Getting Started
As with any woodworking project, protective clothing and safety glasses should be worn.

Handling and Storing

• Trex weighs more than wood and it's more flexible. Special care should be taken when handling. Do not attempt to lift similar volumes of Trex as you do wood.
• When storing Trex Wood-Polymer lumber at the job site, be sure to place on a flat surface.
• When stacking units, supports should start at each end and be spaced 24" on center. Supports should line up vertically.

Units of 12' Trex lumber on level ground.		Units of 12' Trex lumber on uneven ground.

Cutting and Drilling

• For best results, use carbide tipped blades and router bits. Blades with fewer teeth (18-24 for 7-1/4" circular saw blade) work best.
• Trex’s workability is outstanding. Unlike wood, with Trex you won't need to be concerned about grain direction or knots.
• When drilling large or deep holes, periodically lift the drill out of the hole to draw the shavings out.

Fastening

• is important to install all fasteners perpendicular (at a 90° angle) to the boards.
• Install fasteners a minimum of 1" from board end and a minimum of 1" from board edge. If installed less than 1" from either end of the edge, then the board may split.
• When "toe nailing" to a common joist, pre-drilling is recommended if the screw is placed less than 1-1/4" from the board's end. To avoid predrilling, a "nailer" board may be used and the screw should be installed at a 90° angle into the "nailer" board.
• For best results, Trex recommends the following fasteners, which work well and provide a pleasing appearance without pre-drilling:
  • SplitStop™ — Star Drive Titan 3 Composite Screw
  • Dexxter™ Composite Screw
  • FastenMaster® TrapEase® II Composite Screw
• Other fasteners such as standard composite deck screws, NailScrews®, trim head screws, ring shank nails, and conventional exterior grade deck screws also work well, however screws holes may need some reworking to give a smooth, aesthetic appearance.
• A method to reduce dimpling is to drill a 1/8" deep pilot hole using a drill bit that is the same diameter as the screw head. Caution should be used to not countersink more that 1/4" as this will impact the screw’s holding power.

Gapping

• Trex decking must be gapped, both end-to-end and width-to-width. Gapping is necessary to facilitate drainage and for the slight thermal expansion and contraction of Trex. Another reason for gapping is to account for the shrinkage of the pressure-treated joists. Following the proper gapping will ensure that your deck looks great year after year.
• Width-to-width: above 40° F = 1/4" gap, below 40° F = 3/8" gap.
• End-to-end: above 40° F = 1/8" gap, below 40° F = 3/16" gap.
• Abutting solid objects (walls, posts, etc.): above 40° F = 1/4" gap, below 40° F = 1/2" gap.

Trex Decking and Railing Span Chart
Maximum Recommended Center-to-Center Decking Spans

Residential Decks, Light Duty Docks, Residential/Daycare Playground

Commercial Decks, Boardwalks & Marinas

Maximum Railing Span for all Applications

Note: When installing Trex decking at a 45 degree angle to the joists, be sure to reduce the joist spacing by a minimum of 4”. Trex must be fastened to a minimum of 3 joists.

* These products or applications are not part of the Canadian Construction Materials Centre (CCMC) Evaluation Report, CCMC 13125-R.

Stair Span Chart

Maximum Center-to-Center Spacing Between Stringers

General Construction Facts

• Trex complies with all major model codes issued by BOCA, ICBO, SBCCI and ICC. For detailed information, please see ESR-1190.
• Trex composite lumber (5/4x6, 2x4, 2x6, and 2x8 planks) can be used as exterior decking in combustible construction for light-duty applications, such as in residential occupancies, falling within the scope of Part 9 of the National Building Code of Canada (NBC) 1995 subject to the limitations described in CCMC 13125-R. Evaluation Report, CCMC 13125-R is available at your dealer or through CCMC's web site, http://irc.nrc-cnrc.gc.ca/ccmc.
• Report ESR-1190 is available at your authorized Trex dealer.
• Trex is not intended for use as columns, beams, joists, stringers, and other primary load bearing members.
• Refer to the decking span chart above or ESR-1190 for maximum allowable spans.
• Trex must be installed on level joists to ensure a level deck surface.
• Trex decking has not been evaluated by the CCMC for use as stair treads or where decay and termite protection is required.

Contact: 1-800-BUY-TREX for any further questions

©2008 Trex Company, Inc. All rights reserved. TREX®, the TREX® logo, Trex Origins®, Trex Accents®, Trex Brasilia®, Trex Contours®, Trex Designer Series Railing®, Trex Artisan Series Railing®, Trex Railpost™, Trex Seclusions®, TrexPro®, TrexExpress™ and TrexExpress® logo are either federally registered trademarks, trademarks or trade dress of Trex Company, Inc., Winchester, Virginia.

SplitStop™ – Star Drive Titan 3 Composite Screw is a trademark of Titan Metal Werks, Inc.
Dexxter™ Composite Screw is a trademark of Swan Secure Products, Inc.
FastenMaster® TrapEase® II is a registered trademark of OMG, Inc.
NailScrews® is a registered trademark of Universal Fastener Outsourcing.