How to Replace Deck Railing with Prebuilt Vinyl Railing

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Last Updated: October 27, 2025

This wikiHow contains instructions for replacing deck railing with prebuilt vinyl railing. This process can seem intimidating to some DIYers or homeowners with little construction experience. However, the process is quite simple, and can be successfully performed if you have little to no construction experience. Following these steps will allow one to successfully demolish the existing railing, replace and install new vinyl railing, and even save money!

Part 1

Part 1 of 4:

Demolition

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1
Cut the existing railing into manageable pieces. Use a Sawzall or circular saw to cut through the top rail of the existing railing.
- For ease of removal, do not cut sections larger than 6 feet.
- Make as many cuts as necessary to remove the railing.
2
Remove the balusters from the existing railing. The balusters may be attached to a bottom rail, or directly to the rim joist around the edge of the deck.
- If the balusters are nailed to the rim joist, use a large hammer to knock the balusters free from it.
- If the balusters are attached to a bottom rail, refer back to step 1 and cut the bottom rail just like the top.
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3
Disconnect any existing railing posts. The posts may be attached to existing deck boards, or they may pass through the deck and be attached to the rim joist. Either way, use a large hammer to knock the posts free from their attaching points.
- If the posts are attached to the rim joist, they may have to be cut around the base for ease of removal.
- Use a combination of cutting, prying, and hammering to disconnect the entire post.
4
Remove the railing. To do this, carefully push the railing away from the deck by hand. There should be no secure attachment points to the deck at this point.
- If a post or baluster prevents the railing being pushed off of the deck, refer back to steps 2 and 3 to remove the attachment point.
- Do not hold on to the railing as it falls.

Part 2

Part 2 of 4:

Blocking and Post Installation

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1
Layout the post locations. Measure the lengths of all sides of the deck and determine the midpoint to layout where posts will be installed. Ensure that the spans you decide to use do not extend past the length of the rails you have purchased.
- For example, a 12 foot deck will need a post on each end of the deck, as well as one in the middle placed at 6 feet.
2
Install blocking under each post location. Measure the distance from the rim joist to the inner joist and install 2-2x8 boards stacked on top of each other between the joists.
- Note that the blocking must be installed tightly against the bottom of the deck boards.
- Use 3” deck screws to screw from the outside of the joist into the blocking to secure.
3
Drill holes for the post installation. Each post will be attached to the blocking using four holes. Mark where the post will be placed, then mark the holes to be drilled through the deck boards and blocking below.
- Use a 12” long, 3/8" diameter drill bit to drill holes through the deck boards and blocking.
- Make sure that you drill straight down to avoid crooked holes.
4
Attach the post. Use 5 ½-6” bolts to secure the post to the deck. On the blocking side, use a large washer along with a lock washer to ensure that the bolts can be tightened securely.
- Use a 4 foot level to ensure that the post is plumb before securing.
- If the post is not already plumb, shims can be used on the bottom plate of the post to ensure that it is straight.

Part 3

Part 3 of 4:

Railing Installation

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1
Install the vinyl post jacket. To do this, slide the vinyl post jacket over the installed post. If decorative post bases will be used, they can also be installed at this point.
- All manufacturers will have slightly different designs, so be sure to reference the manufacturer provided instructions when installing vinyl pieces.
2
Measure and cut the railing to the desired length. Measure the distance between the inside edges of the posts that the railing will be installed between. If the railing needs to be cut to fit, use a Sawzall and cut the same length off of each side, top and bottom rail. Doing so will ensure a uniform fit.
- To find the length to be cut from each side of the rail, subtract the railing length from the length between the posts, then divide that number by two. This amount is the length to be cut from each side of the rail.
- For example, The span between the posts is 64” and the length of the railing is 68”. Take 68-64 to get 4”, then divide four by 2. The end result is 2” to be cut from each side of the rail.
3
Attach the railing. Use the provided hardware to attach the railing sections to the posts. All manufacturers will have different attachment styles, so be sure to check the provided instructions. Typically, two screws are used on the top and bottom rail on both sides.
- Use 3” wood blocks to ensure a uniform height across the railing.
- Manufacturers may also provide a permanent support block to be installed under the center of the bottom rail.
- Note that the vinyl screw covers may need to be slid over railing before attachment.

Part 4

Part 4 of 4:

Finishing Touches

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1
Install the railing attachment covers. Attach the vinyl sleeve covers to railings, per the manufacturer’s instructions. You then may need to secure the railing attachment covers with clips, screws, or PVC cement, depending on the manufacturer’s instructions.
- Most likely, both the top and bottom rails will have a vinyl cover to hide the screws on the attachment points.
2
Install post caps according to the manufacturer’s instructions. The post caps can be secured to the top of the post in a variety of ways, such as PVC cement, clips, or screws. Slide the post cap over the top of the post and secure as required.
- If PVC cement is the attachment method, ensure that both the post and the inside of the post cap are clean and dry. Doing so will allow for a stronger bond.