4" to 6" Adjustable 4 piece post trim base by RDI

Contractor Rebates
(30 reviews) Write a Review
$10.99 - $15.99
1.00 LBS
Calculated at Checkout

Adjustable 4-Piece Post Trim Base by RDI

Khaki on Sale - 20% off! *

Trim comes in 4-pieces that slide into one another creating sizes between 4" - 6"

For use when sliding over an existing post is NOT an option!

Can also be used as a standard base post trim.

If you’re working on a deck or porch project and are looking to evoke the timelessness of beveled wood details, consider adjustable four piece post trim by RDI as an equally alluring solution for a fraction of the hassle and cost. Not only is this adjustable deck post base incredibly easy to work with, but it is just as attractive as any wood option. The flexibility this adjustable four piece deck post base offers makes it an appealing addition to any railing or deck, as long as your posts range in size anywhere from 4" - 6". Available in White, Khaki, and Sand, these post bases are sure to add polish to any job, whether you are a contractor or a homeowner making a few improvements.

Crafted using weather-resistant vinyl, RDI’s adjustable deck post base can withstand the elements and is incredibly low-maintenance. Plus, RDI offers a lifetime warranty on all of its products, so you never have to worry. As a bonus, Deck Expressions offers free domestic shipping on all orders over $99.99, so you can afford to stock up on everything you need to finish your project and make your home look great.


  • Post trim adjusts to fit posts from 4" to 6"
  • Great for Post Sleeves 
  • Comes in 4 - pieces
  • Heavy duty plastic vinyl

Click HERE for Warranty:



Width - 1-1/4"

Height - 1-1/16"


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30 Reviews Hide Reviews Show Reviews

  • 5

    Posted by Henry on Aug 6 2022

    I purchased the base to go around the 5" turned porch post. They install easily after the post is installed using the marked notches to cut to the correct dimension by sliding the four pieces into one another without a seam for a secure fit that doesn't seem to pull out. The decorative trim looks great on the deck and goes well with the style of the porch. The one thing that I am a little put off by is that the inside corners do not match the post's rounded corners and leave a gap. Otherwise, I recommend this product.

  • 5
    4 piece vinyl post wrap by RDI

    Posted by David on Oct 11 2021

    A nice finishing touch to the RDI post wraps. They give continuity from the posts to the ceiling and floor. Just a recommendation to the install instructions. Cut them to size with a saw for a clean edge, and cut them a bit larger than their markings. The tolerance is small to get them to go together properly, and you can always cut them shorter, but not longer.

  • 5
    3.5" to 6.5" Adjustable 4 piece post trim base

    Posted by Ray on Jul 25 2021

    Trim was easy to install, just cut to size & simple installation. Looks great , great appearance , a cost effective option to wrap a post. Nice product

  • 5
    Nice tight fit

    Posted by B Max on Dec 31 2020

    Trim fit perfectly around the 4 piece vinyl post wrap. Very simple to assemble

  • 4
    Works well

    Posted by Randy Rekrab on Nov 23 2020

    These were easy to cut and install.
    Full video installation and review here:

  • 5
    Column wraps and trim

    Posted by Rich Libert CCHH on Oct 19 2020

    Simple installation, great appearance , a cost effective option to wrap a post. Nice product

  • 5

    Posted by Frank on Sep 26 2020

    Very easy to install. Notches on back for cutting.

  • 5
    Adjustable Post Trim Kit

    Posted by Charles Tackney on Sep 22 2020

    These are really excellent, and surprisingly hard to find elsewhere. Great for existing or on site post base (or top) installation. Especially with lumber that is not "true size"!! I found it easier to cut them on a little miter box I had for a clean accurate size adjustment. Test the size before cutting, make a mark to allow the clips to engage and all works out well. Some people caulk the tiny gaps, but my posts are on zinc stand-offs and I think a tiny gap is better for weathering.

  • 5

    Posted by Shawn on Jul 17 2020

    The adjustable post trim is great. It fit exactly how i needed it. It shows exactly where to cut on the inside of the trim. For the most part they are secure however it seems they could use a little more support. I have not done it yet but will be adding some silicon on the back side to keep them in place and from accidentally coming apart. Other than that they look great with the post wrap.

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