Trex© Decking & Railing Usage Guidelines
Trex® composite lumber is suitable for a wide range of uses such as decking, railing and landscaping. Trex composite lumber 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 Span Chart for specific requirements or consult the Trex composite lumber building code listings (National Evaluation Service - NER-508 or ICBO Evaluation Service Report ER-5747).

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

Handling Trex Composite Lumber

• Trex composite lumber 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 lumber as you do wood.
• When storing Trex composite 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.

Cutting and Drilling Trex Composite Lumber

• For best results, use carbide tipped blades and router bits.
  Tip: Blades with fewer teeth (18-24 for 71/4" circular sawblade) work best.
• Trex composite lumber's workability is outstanding. Unlike wood, with Trex composite lumber 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.

Nailing and Fastening Trex Composite Lumber

• Hot-dipped galvanized or stainless steel nails or screws are highly recommended to take full advantage of the durability of Trex composite lumber.
• Consult the supplier of the framing lumber for additional recommendations on fastener coatings as some preservatives can affect fastener life.
• More force is required to drive a nail into Trex composite lumber than regular wood. Hold nail while hammering until it is driven ½" to ¾". Hitting a nail with full force when it is not driven in may cause it to fly out.
• Nail guns work very well with Trex composite lumber.
• For cold weather installations or when using wood screws or lag bolts, pre-drilling may be necessary. Do not drill holes any larger than ¾ of the screw/bolt diameter. Pre-drilling is generally not required for self-tapping or deck screws.
  Tip: Most screws will cause Trex lumber to "mushroom" up over the screw head. Simply tap down with a hammer to hide the fastener or pre-drill to reduce the "mushroom" effect.

Gapping Trex Composite Lumber

• Trex composite products are engineered to last.
• Following proper gapping requirements will ensure your deck looks great year after year, preventing debris build up by facilitating drainage.
• Trex composite decking must also be gapped end-to-end, based upon the length of the board and the temperature at installation. For end-to-end gapping installations below 60°F - gap 3/16”, above 60°F - gap 1/8”.
  The required width-to-width gapping is 1/4”. For below 40°F installations, 3/8” gapping is recommended.
• Trex composite decking must also be gapped when decking is abutting a wall, based upon temperature at installation. (Same rules as above.)

Cleaning and Care of Trex Composite Lumber

• For stains caused by mold, mildew, berries and leaves, conventional deck washes containing detergent and sodium hypochlorite work well.
• For rust stains, ground-in dirt and grime, use cleaners containing oxalic or phosphoric acid which are commonly available in home centers and hardware stores.
• For tougher stains, such as oil or grease, scrub with a detergent containing a degreasing agent as soon as the stain occurs.
• Periodically clean out gaps between Trex composite boards with a flat tool to ensure proper drainage.

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

Residential Decks, Light Duty Docks, Residential & Daycare Playground Commercial Decks, Boardwalks & Marinas

	Residential Decks, Light Duty Docks, Residential /Daycare Playground	Commercial Decks, Boardwalks & Marinas
Loading	100psf	100psf	200psf
5/4 x 6	16"	16"	12"
2 x 4, 6, 8	20"	20"	16"
2 x 6 HS24	24"	24"	16"
2 x 6 Stairs	12"	12"	12"

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.

General Construction Facts

• Trex composite lumber complies with all major model codes issued by BOCA, ICBO, SBCCI and ICC. For detailed information, please see NER-508 and ICBO ES ER-5747.
• Reports NER-508 and ICBO ES ER-5747 are available at your authorized Trex dealer.
• Trex composite lumber is not intended for use as columns, beams, joists, stringers, and other primary load bearing members.
• Refer to the decking span chart above or NER-508 or ICBO ES ER-5747 for maximum allowable spans.
• Trex must be installed on level joists to ensure a level deck surface.

Trex Designer Series Railing™ Installation Instructions

Step 1 - Install Posts
Railing Assembly Tool can also be used to plumb the post and set the bolt holes. Attach to rim joists and wood support blocking with 1.2" diameter carriage bolts. Do not notch posts. bolts must be vertically spaced no less than 51.8" apart. Top bolt must be a least 2" from the top of the deck, and the bottom bolt must be at least 1" from the bottom of the post.

Step 2 - Post Skirts (when applicable)
Slide Trex® Post Skirts over each post, resting them on the surface of the deck.

Step 3 - Set Railing Support Brackets (RSB)
Insert two RSB’s into the Railing Assembly Tool as directed. Wrap the Railing Assembly Tool around the post, resting the bottom of the tool on the top of the Post Skirt. If Post Skirts are not being used, temporarily insert additional 5/4 board below tool. Assemble each RSB to the post using (2) screws provided (#9 deck screw x 15/8''L). Once each bracket is assembled to the post, remove the Railing Assembly Tool. Repeat this step until all sections are complete.

Step 4 - Space Your Balusters
Lay the Railing Assembly Tool face up, and place balusters in designated slots as shown. Align top and bottom rails. Insert all balusters for that section into the channel on the top rail. Use the Railing Assembly Tool to properly space each baluster in the top rail. When spacing the balusters, make sure that the distance from the end of the top rail and the first baluster are equal on both ends.

Step 5 - Securing Balusters to Bottom Rail
Place the bottom rail on its side, ensuring that the side with the lip is up. Slide the Railing Assembly Tool face up, adjacent to bottom rail. Using the marked distance that matches the first baluster on the top rail, place the baluster in contact with the lip of the bottom rail. Once in place, nail through the underside of the bottom rail into each baluster. If using screws, Trex recommends pre-drilling. (Hint: Groove in the bottom rail indicates the center location of the baluster for nailing.)

Step 6 - Securing Balusters to Handrail
Using a nail gun, (2'' - 16 gauge nails) secure each baluster by inserting a nail through the lower side portion of the top rail into each baluster. Align the bottom rail so it is the same distance from the first baluster as the top rail. Nail both sides of handrail for added stability.

Step 7 - Attach Your Support Blocks
Nail through the sides of the bottom rail into the support blocks (See image in Step 6). Support blocks are 4'' long and are required every 18''.

Step 8 - Securing Railing Section to Post
Place the assembled railing section on the RSB’s already secured to the posts. Using (2) screws provided, secure the top rail to the RSB’s.

Step 9a - Securing Bottom Rail to Post From the Top
Secure the bottom rail by installing a screw through the top of the bottom rail into the outer-most hole of the RSB.

OR

Step 9b - Securing Bottom Rail to Post From the Side
Using a nail gun (2'' - 16 gauge nails) at a 45° angle, place a nail from the bottom rail into the rail post. Position the nail 11/4'' up from the bottom of the rail and 1'' in from the rail post.

Trex Tip for Designer Rail Installation

Follow these steps to achieve a tight fit for your railing and prevent balusters from loosening once installed.

When securing balusters to Bottom Rail, pre-drill connection using 1/8" to 5/32" bit and secure connection with 2" deck screw instead of nails. The groove in the bottom rail indicates the center location of the baluster for drilling.

When securing balusters to Top Handrail, fasten by securing one (1) 2-1/2" - 16 gauge finish nail through the outside of top rail, ensuring that the nail firmly secures both legs of the Top Handrail and the baluster.

Above specs referenced from www.trex.com.

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