Flexible J Channel

Engineered To Be The Best Flexible J-Channel!

FleX-J, the flexible j-channel from Extrudex boasts a unique design and material that sets it apart from the competition. The features of Extrudex’s flexible j-channel, FleX-J, make it the best option for the installation of round and arch top windows.

FleX-J is unique in that it offers a true 1” face, one of the largest available on the market today. Designed with a UV protected, antimicrobial, and dual durometer materials, the Extrudex FleX-J is the most stable extruded flex j-channel in the world.

Superior Design

See why FLex-j is the superior j-channel on the market

Superior design. Our enhanced design features extend the semi-rigid material partially up both the Face and the Nail Fin ends, allowing the Extrudex FleX-J to hold its shape around the tightest radii. This reduces the possibility of deforming the 1” Face during installation. With two available sizes of flexible j-channel for vinyl siding (¾” and 1-1/8”), each piece of FleX-J flexible j-channel provides the proper fit with siding, limiting the distortion associated with “one-size-fits-all” j-channels.

A Top that’s curled-over

A significant design aspect of flex-j

Another unique aspect of the FleX-J by Extrudex is its “curled-over” top on the Face side, making it the only flexible j-channel on the market with this feature. This feature provides the same professional finish found with rigid j-channels. The FleX-J also offers the longest nail fin (1.67”) available in the world of curved j-channel. The nailing fin is tapered, ensuring easy installation. Our flexible j-channel for vinyl siding can streamline installation times and provide long-lasting results. The FleX-J is pretreated with UV inhibitor and fungicide to ensure that our curved flexible j-channel is long-lasting and continues to look good.

3/4” FleX-J Channel
1 1/8” FleX-J Channel

FleX-J Specs

Flex-J Shipping Information


Carton Size

Lineal Feet/Carton

Delivery Time
5 working days for stock items

Painesville, OH 44077

Flex-j Colors

meeting the needs of your project

We currently offer our FleX-J channel in white, clay, sand, and light gray. Need to match a specific color? The FleX-J by Extrudex is paintable!

Follow these simple guidelines for painting your curved j-channel:

Talk to a professional about pre-treatment of the FleX-J surface prior to paint application.
Use a urethane or acrylic-based paint on your flexible j-channel (such as Polane® 2-part system from Sherwin Williams).


Installing For Curved Openings

The Extrudex FleX-J helps with installing flexible j-channel around curved windows, such as round tops and half-round windows. To install FleX-J vinyl siding J channel around the top of these types of windows, please download these instructions in our installation manual.