April 16, 2026
What the Twenty-Five Year Composite Warranty Excludes on a Florida Dock
Your quote came back and composite decking stopped you cold. Here's what that number actually covers — and what to check before you sign anything.
EXCERPT: The twenty-five year warranties on capped composite cover material defects and exclude installation error, which puts the expansion gap and the fastener system at the center of what a dock owner is actually buying
What the Twenty-Five Year Composite Warranty Excludes on a Florida Dock
The better capped composite boards carry twenty-five year warranties. Those warranties cover material defects. They do not cover installation errors, and on a dock the most common installation error is a gap that wasn't left.
Composite moves with temperature more than wood does. On a south-facing dock in July, where surface temperatures reach levels uncomfortable to walk on barefoot, the expansion gap at the board end is what absorbs that movement, and the manufacturer specs are written for exactly that condition. A contractor who installs tight to the board end has built a claim the homeowner will lose, because the resulting damage is an installation error and the warranty excludes it.
Composite decking dock with Adirondack chair and boat on calm lake, Central Florida waterfront
What the major manufacturers sell now — Trex, TimberTech, Azek, Fiberon — is capped composite: a polymer shell wrapped around a wood-plastic core. The material began as ground wood fiber mixed with plastic and pressed into boards, and the early uncapped versions got hot enough in direct sun to blister. Twenty years of reformulation produced the capped product, which resists staining, holds its color, and handles moisture in a way wood does not.
Most composite is priced and spec'd for residential decks: shade, moderate exposure, stable ground underneath. A dock is full sun all day, heat reflected off the water, and a structure that flexes with wind load and boat wake, sitting over water twelve months a year in humidity that doesn't meaningfully relent in any season. In that environment capped composite outperforms uncapped, and lighter colors run cooler underfoot.
Pressure treated lumber remains a legitimate choice and is still widely used in dock construction. It requires periodic sealing or staining. Left alone it grays, checks, and eventually softens at the fastener points.
Two hidden fastener systems cover most composite dock work. The Camo system uses a jig that drives screws at an angle through the board edge into the joist below, leaving a clean face with no visible hardware. Trex has its own clip system, which the product is designed around. Both leave the surface clean, and both are specified for the material.
Camo hidden fastener jig and screws on composite decking, dock installation tool
Trex hidden clip fastener system installed between composite deck boards, clean face installation
When you're reading a composite quote for a Florida waterfront dock — seven thousand dollars for boards, before framing and before labor — the board cost is the fixed part of the number. What varies between marine contractors is the framing spec, the expansion gap discipline, and the fastener system.
Before signing, ask how the contractor fastens the field boards and what system goes on the handrail posts.
Published by
Horizon Marine — Docks & Seawalls
Central Florida's dock and seawall contractor. Free waterfront assessment. License #SCC131154313.
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