How to Install Trex Signature® X-Series™ Cable Railing

To maintain access to the nuts and bolts, both the anchor and pass-through posts must be installed over a space that does not have a joist directly beneath it. The railing posts will not be strong enough if they are attached to deck boards without additional support, which means blocking will be required. Blocking is always easier to install while building the frame of a deck. But in many cases, blocking can still be installed if you are just replacing an existing railing and there are deck boards in place.

Step 1: Install Post Blocking

The blocking you install should be made of at least 2x8 material. However, many deck builders install the blocking out of the same size lumber as the joists, which is a good way to use up scrap wood. Start by cutting two blocks the length of the space between the two joists in the area where the post will be installed, and sandwich the blocks together with screws. Install the blocks horizontally, level with the top surface of the joists. Cut and install cross braces, so that the blocks are completely surrounded by either joists or cross braces. This will typically require one cross brace on the blocks located at the end of the deck, and a brace on either side of the blocks located along the sides of the deck. Use three, 3-in. screws compatible with pressure treated wood wherever two boards intersect.  

Step 2: Protect Blocking with Joist Tape

Before you install the deck, cover the joists, blocking, and cross braces with joist tape. Joist tape helps protect horizontal framing components from standing water and can prolong the life and structural integrity of your deck frame. If you install cable rail over existing decking, cover the blocks and cross braces before you slide them into place from underneath.

Step 3: Mark and Predrill Bolt Holes

Set each post in the desired location, and use the bolt holes in the bases of the anchor posts to mark the location of the bolt holes that you will drill through the decking and blocking. Make sure every hole is over a block and located at least 1 in. inside any joist or cross brace location, so there will be enough room to install the nut on the bolt. Once the holes are marked, drill the four holes using a 9/16-in. drill bit.

Step 4: Install Bolts

Slip washers onto the bolts, and then insert the bolts through the anchor post bases and the holes in the deck boards and blocks. With the barbs facing upward, thread the tee nuts onto the bolts until they are flushed with the bottom of the bolts. Then use a hammer to tap the barbs on the nuts into the wood on the bottom of the blocks. This will hold the nuts in place and prevent them from spinning while you turn the bolt heads from above. Use a 3/4-in. wrench or a 3/4-in. socket to drive the bolts down.

To prevent pushing the barbs loose from the wood, avoid pressing down on the bolt heads as you turn them. Use a level as you tighten the bolts to ensure the posts are perfectly plumb. Minor adjustments can be made in the posts by tightening certain bolts slightly more than the others. For posts located over framing that is not consistently level, you may need to install composite shims under one or more sides of a post base. 

Step 5: Install Pass-through Posts

The center of all pass-through posts should align with the center of the anchor posts. For 12-ft. railing configurations where only one pass-through post is required between anchor posts align the pass-through posts so they are centered exactly between the two anchor posts.

For 18-ft. railing configurations, where two pass-through posts are required, align the two pass-through posts so the space between all the posts are the same distance. Mark the hole locations using the base on the pass-through post as a template, and install them the same way you installed the anchor posts. Set aside the bolt cap components until the rest of the railing has been installed.  

The location of the turnbuckles is a personal preference. They can be located on either side of a railing section, or they could be staggered so that half are on one side and half on the other side of the same section. Wherever you place the turnbuckles, adhere to the recommended tightening sequence explained below in Chapter 5.

Step 1: Attach Cables to Infill Adapters

For each section, insert all the short cables (the ones with the turnbuckles) through the holes in one of the cable infill adapters, and then insert the long length of the cables through the holes in the opposite cable infill adapter.

Step 2: Slide Cable Infill Adapters into the Posts

Remove the appropriate side covers on the posts and slide the cable infill adapters into those same slots. The cable infill adapters should be inserted so that the holes closest to the ends are located towards the bottom of the posts.

Step 3: Thread Cables Through Braces and Pass-through Posts

Remove the small cap/cover on the end of each long cable, before you thread each one through the corresponding holes in the brace. For longer railing configurations, follow the same procedures for any additional pass-through posts and braces that might be required. To keep the braces out of the way until they are set, you can slide them over to the nearest posts and temporarily secure them with painter’s tape. Do not attach the cables into the push-to-connect fittings at this time.

Even if you tried to install all the posts at the same distance apart, do not assume all the top rails will be identical in length. Each top rail section should be measured and cut to size individually. The aluminum rails can be cut with a miter saw fitted with a carbide blade. A sharp blade with a higher tooth count will result in a smoother cut. And always lower the blade slowly at the beginning and throughout the cut.

Step 1: Cut Top Rails to Length

To determine the cut length of each top rail, measure the span between the inside/facing edges of two posts and adjust the final size based on the following configurations:

• Cut-length between two anchor posts
  • Span – 1/4 in.
• Cut-length between an anchor post and pass-through post
  • Span + 5/16 in.
• Cut-length between two pass-through posts
  • Span + 13/16 in.

Step 2: Dry Fit Top Rails and Brackets

Once the top rails are cut to size, insert the appropriate brackets on the ends, making sure they are fully seated. Then insert all the brackets onto the posts. For spans with three top rails and two pass-through posts, install the center top rail onto the pass-through posts first, then install the outer top rails.

Step 3: Pre-Drill Screw Holes for the Brackets

Once all the top rails and brackets are fitting properly, use a marker or pencil to mark the hole (located on the underside of the top rail/bracket) that will accommodate the #8 x 1/2-in. screws that hold the brackets permanently to the top rails. Remove the top rails and drill the holes using a 9/64-in. drill bit.

Step 4: Attach Top Rail Brackets to Anchor Posts

Once the bracket screw holes have been drilled, set the top rails back in place. Next, lift each top rail partially out of the anchor posts and slide the top rail, locking assembly into the dovetail on the top of the bracket. When the top rail bracket is back in place, the set screw on the top rail locking assembly should be accessible above the top rail. Use a 5/32-in. Allen wrench to tighten the set screws.

Step 5: Attach Top Rail Brackets to Pass-Through Posts

Secure the brackets on top of the pass-through posts with two barrel bolts and set screws. Tighten the screws using a 1/8-in. Allen wrench.

It’s VERY IMPORTANT to use sharp cable cutters to cut the cables to size. Using standard wire cutters or tin snips will cause the cables to fray, making them impossible to insert into the push-to-connect fittings. The wrenches required to tighten the cables are included in the kits (one per kit). Each cable should be tightened to 100 lbs. of tension as measured with a cable tensioning gauge. Overtightening could distort the infill adapters.

Step 1: Install Push-To-Connect (PTC) Fittings

Thread the PTC fittings into the turnbuckle on each short cable, until the threads on the PTC fitting just disappear into the turnbuckle.

Step 2: Trim Down Cables

Pull each cable hand-tight and mark them using the reference line on the PTC fitting. Then trim down each cable with sharp cable cutters.

Step 3: Install Cables into the Push-to-Connect Fittings

Push the end of each long cable into the corresponding PTC fitting. Then seat the cable by rotating it clockwise approximately 1/4 turn into the PTC fitting. Hand-tighten the cables by holding the PTC fitting (and cable) in a fixed position and rotating the turnbuckle.

Step 4: Tighten the Cables

Use one wrench to prevent the PTC fitting from turning, and a second wrench to rotate the turnbuckle to tighten the cable. Tension each cable to 100-lbs. Start with a center cable and then tighten the cable below it. Tighten the cable above the center next, and then continue in this high-low pattern until you work your way to the top and bottom cables.

Step 5: Install Center Cable Braces

Slide the center cable brace halfway between two posts, ensure that it is plumb, and then secure it at the top and bottom by tightening the set screw with a 3/32-in. Allen wrench.

You’re almost done! Before finishing up these last few steps, double check that all the posts feel solid and sturdy and that all the cables were tightened properly.

Step 01: Install Bracket Screws

Install the #8 x 1/2-in. screws that hold the bracket to the top rails. Be careful not to let the chuck of the drill/driver mar the posts while installing the screws. Using a long driver bit or an angle adapter will help prevent this.

Step 02: Install Inserts and Caps

Slide in the inserts that cover the bracket set screws into the anchor posts, and then install the post caps. Install the bolt caps starting with the inner cap. There is a hexagonal shape molded into the top of the inner bolt caps. Line up that shape with the bolt heads and push the inner caps in place. Finish by installing the outer caps over the inner caps.

Step 03: Call for an Inspection

Make sure you call and have your new railing inspected. The inspector may want to see that you followed the instructions (especially the blocking and the anchor bolts), so keep the installation manual on hand until your inspection has been passed.

Step 04: Celebrate!

Decorate your deck with some comfortable furniture, fire up the grill, and invite your friends and family over to share some tasty BBQ and to enjoy those stunning, unobstructed views. 

The installation steps for installing cables between posts on stairs or between posts that meet at an angle other than 90 deg. are very similar, with a couple exceptions. The primary difference for angled posts is that you will need to purchase compound swivel brackets which are sold separately. For cable rails on stairs, the max length between anchor posts is less than six feet, and you will need to purchase specific Trex Signature X-Series Stair Cable Rail kits that include the compound swivel brackets. Also, building code requirements for the handrail heights vary. Check with your local building official to find out the code requirements in your area so you can purchase the appropriate size posts and rail configurations. Check out the manual for installing cable railings on stairs for more info.