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The AZEK TimberTech Impression Rail system offers clean lines, unobstructed views, and flexibility to accommodate stairs, angles, and straight runs up to 10 feet. This system is available in 6’, 8’, and 10’ sections, so plan your posts to fall within these guidelines. Be mindful of accents you plan to add, such as lighting—as this can affect the layout.  

Before you get started, draw out a plan, make accurate measurements, and lay out the system with ample space to organize the AZEK pieces in a way that doesn’t obstruct your work area. It’s important to make sure you have all the necessary parts and equipment on-site before you begin your installation. Be sure to consult the AZEK installation guide, making sure you have all the components (and quantities) listed on page two—especially the Impression Rail install tool. 

Step 1: Prep the Deck with Blocking

Determine where the posts will be located. Install blocking and bracing to ensure that the posts will anchor securely and rest plumb and level.

The deck in our video had space underneath, making it a perfect candidate for a top-mount install. We used a pressure-treated material—laid flat and doubled up underneath the deck surface—to give the posts a proper footing. Install 2 x 8 (as a minimum) blocking, which we secured with 16d penny nails.

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Step 2: Install Posts

Start by drilling 3/8” holes through the decking and blocking, matching the bolt hole pattern on the posts. We started with placing posts at the base and top of the stairs. It’s important to know the angle of the stairs on your deck. The AZEK TimberTech Impression Rail system includes a pre-set 35 degree step bracket, which can adjust to plus or minus 2 degrees during installation. AZEK also manufactures a fully adjustable stair bracket. Use the Impression Rail installation tool to guide your drilling, paying careful attention to posts laid at an angle.

Position and secure the posts using 3/8” x 6” bolts, along with the mounting plate, washers, and nuts. We used the help of a mallet and some leftover cardboard to help guide our bolts into our pre-drilled holes, and then tightened each bolt into place. It’s important to check that each post has been placed straight; use a level after each post is installed.

You can then continue to add posts along your deck, measuring carefully along the way so that each post is an equal distance from the edge of the deck. Continue to add blocking under each post to secure it solidly.

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Step 3: Install Skirts

Slide the skirts over the post. You’ll want to make sure all of your bolts are tightened completely, to ensure that the skirt lays flat and even. See the installation guide for further instructions and helpful diagrams.

Step 4: Install Bottom and Top Brackets

Resting the Impression Rail installation tool on the skirt of the post, pre-drill bottom bracket holes in the post. Then use the guides on the tool to indicate where to drill your holes. Note the direction that the rails are to be positioned, and drill appropriately. For the deck in the video above, we had to drill into the post at an angle to accommodate how the post was positioned. This allowed us to work with the layout of the existing deck underneath. We didn’t have a 90 degree corner on the deck at the top of the stairs where the post rested, which added a challenge to our installation.

Place the Impression Rail installation tool flush with the top of the 3” post (or flush with the top of the window on the 2” post), and use the appropriate holes as a guide to pre-drill top bracket holes into the post.

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Step 5: Install Bottom Railing

Now you’re ready to place the bottom rail in the bottom brackets of the posts. Secure the snap covers onto the bottom rail.

Step 6: Install Balusters

Gather the number of balusters you need for this section of railing, based on the number of holes in the bottom rail. Snap each baluster into place. It’s helpful to have a second set of hands for this next step. Now install the insert on the balusters by aligning the holes with each baluster, making sure the balusters are fully secured in the insert.

The two top bracket covers should slide onto the top rail. Now set the top rail on the insert, and inside the top brackets at the same time. Snap the top rail over the insert until the top rail is fully engaged.

Step 7: Install Top Railing

Attach the top and bottom bracket to the posts using the provided ¾” pan head screws.

Be sure to measure the distance between posts at the top and bottom bracket locations. Once you cut the top, insert the bottom rails and rail covers 13/16” shorter than the distance you just measured. Rather than cutting off one end, determine your center point between the two posts. Then, measure from that center mark to the ends, and make two cuts. Again, because of the layout of the existing deck in the video above, we placed the rails at an angle and therefore had to cut at an angle too.

Since our railing was longer than 72”, we added two foot blocks to the bottom rail that rest on the deck and help support the rails. You’ll want to pre-drill the center of the underside of the bottom rail with an 1/8” drill bit. Next, attach the foot block connector to the underside of the bottom rail using the provided 1” pan head screw. Secure the cut foot block by pressing it onto the foot block connector.

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Step 8: Fasten the Bracket to the Top Rail and Install Top Bracket Cover

Using the holes on the side of the top brackets as a guide, pre-drill 1/8” holes on both sides of the top rail. Now fasten the top bracket to the top rail using the provided 3⁄4” flat head screws. Slide the cover over the railing and the bracket; doing so will cover the top bracket and rail ends.

Step 9: Install Post Caps

A rubber mallet should make quick work of securing the post caps to the posts. With that, your AZEK TimberTech Impression Rail system is complete!

Installing AZEK TimberTech is an efficient, intuitive process if you follow these simple steps. As always, AZEK Building Products have earned their trusted reputation by providing long-lasting, beautiful solutions for your home, including outdoor decks—one of the best ways to enjoy the Pacific Northwest.

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