How to Bend Composite Decking

Curved edges and inlays can make a deck feel custom. But bending composite decking isn’t as simple as flexing a board. Whether a board can be curved, and how, depends on the manufacturer and the product line. This guide explains how the process works in general, what to confirm before you start, and the risks to plan for.

Can you bend composite decking?

Sometimes. Some composite decking is designed to be curved, and some is not. Always confirm with the manufacturer before you buy or cut anything.

For Trex, the company says it offers decking and railing options capable of being custom curved, and recommends calling 1-800-BUY-TREX to confirm whether your material is recommended for heating and curving. Trex’s decking installation guide states that Trex Enhance decking cannot be curved.

Can you bend Trex decking?

Check your specific product line first. Trex says some of its decking can be custom curved, and Trex Enhance cannot. If you want a curved layout, ask Trex which product fits your design, and consider working with a builder experienced in curved profiles (Trex suggests using its Find a Builder tool).

How does the bending process work?

The general process looks like this. Your manufacturer’s instructions always take priority.

Confirm the product. Ask the manufacturer whether your boards can be heated and curved, and what method they recommend.
Plan the curve. Sketch your layout, decide on the radius, and think about traffic flow and seating. A flexible curve ruler or a template helps you plot the shape.
Heat the board as the manufacturer directs. Heat makes composite boards pliable. The right method, temperature and time vary by product, so don’t improvise.
Shape it on a support or form. Guide the board along your planned curve with gentle pressure, and hold it in place until it has cooled completely.
Install on protected framing. Curved layouts expose more board edges and cut ends, so protect the joists beneath them. Joist tape is one way to protect the tops of your joists from moisture.

Can you bend composite decking with a heat gun?

Heat guns concentrate heat, which makes it easy to overheat one spot. Too much or uneven heat can discolor, blister or soften a board. Trex notes its decking can soften at fairly low temperatures, and damage from extreme heat may not be covered by the product warranty. Ask the manufacturer what heating method it recommends for your boards, and check your warranty before you try one.

Bending vs. warping

A board that bends by itself over time isn’t a curve by design. If your boards are warping or bowing, see our guide on whether composite decking warps.

Risks to plan for

Warping and cracking from heating too fast, unevenly or with too much force.
Overheating, which can discolor or damage the surface.
Misshapen curves when supports are missing or the board is released before it cools.
Warranty issues, if you heat or modify boards in a way the manufacturer doesn’t recommend.

Other ways to get a curved look

Cut curved edges with a jigsaw or router instead of bending boards (see our guide to essential tools for building a deck).
Plan curves into a multi-level layout (see our multi-level deck ideas).
Factor in the cost: curved cuts and rounded edges can add labor (see our deck installation cost guide).

Dave Kile

Dave Kile is the owner of IBP, LLC, the company behind some of the decking industry’s most successful innovations, including Trex® RainEscape®, Trex® Protect™ and Trex® Seal. Over the past three decades, he has achieved incremental success by immersing himself in the industry, listening to customers and bringing new products to market that improve efficiency and effectiveness.

How to Bend Composite Decking