Dock Materials in Florida: Wood vs Composite Decking, Pilings, Height and Electrical

Pressure-treated southern yellow pine is the lowest first cost, and Florida boaters on The Hull Truth report it checking, splitting and throwing splinters within about 12 months. The same threads recommend cypress and ipe, with ipe holding up around 20 years. On composites, owners flag mold on some early Trex boards, heat and slipperiness on dark colors, and name Azek and MoistureShield as running cooler and Tandeck as having no wood content. [thehulltruth.com]

Composite boards generally need closer joist spacing than wood, so a wood-to-composite swap on an old frame can mean adding joists. [thehulltruth.com]

Does composite decking get hot in Florida? Owners say dark boards do, and that lighter colors and the newer capped products run cooler. Barefoot comfort at two in the afternoon is worth testing with a sample board on your seawall cap before you order a dock's worth.

If you are replacing an existing dock in the same footprint, the state exemption lets you use different construction materials and make minor deviations, so a wood-to-composite change does not by itself trigger a new state review. [flsenate.gov]

Owner reports are forum posts, not test data. Ask for a sample and a spec sheet from the manufacturer for any board you are considering.

Wood pilings for salt water are treated to 2.5 pounds of CCA per cubic foot, the maximum retention for treated softwood, and can be fitted with sleeves, wraps and caps to slow attack at the waterline. [decks-docks.com]

The spec to ask for is AWPA use category UC5B or UC5C, which is the salt-water rating. A supplier's brochure figure of 30 to 50 years or more assumes that treatment; the same supplier gives 25 to 35 years on the Gulf Coast and five years or less for untreated wood there. [americanpoleandtimber.com]

CCA and ACQ are the industry-standard treatments for marine lumber. For framing that stays above water look for UC4C; for anything in the water, UC5. [buildingproductsplus.com]

Concrete and fiberglass composite pilings take marine borers off the table, because shipworms are wood-boring mollusks that tunnel into timber. They cost more up front and concrete needs heavier equipment to set, which is part of why water access shows up in every dock quote. [blogs.ifas.ufl.edu]

Hardware is the quiet failure point. Ask for stainless or hot-dip galvanized bolts, hangers and through-rods; plain zinc-plated hardware corrodes fast in salt spray, and a dock is only as strong as the connection between piling and stringer.

Tide range decides this more than anything else, and in Biscayne Bay it is small. NOAA's published bench mark sheet for the Virginia Key station puts mean high water 0.661 meters above mean lower low water and mean low water at 0.040 meters, so the everyday swing is about two feet. [tidesandcurrents.noaa.gov]

A fixed, piling-supported deck is set once at one height, which works when the water moves in a band that narrow, and it lets the deck and the boat lift share the same pilings. A floating dock rides the water instead and keeps the same step down into the boat all day, so it earns its place where levels swing widely, or as a low-freeboard add-on for kayaks and PWCs beside a fixed dock.

One floating-dock manufacturer describes a floating dock riding out a 12-foot surge. That is a single anecdote, and a floating dock still needs guide piles and connections that survive the storm. [accudock.com]

The state exemption treats both the same: it covers docks held in place by pilings or a floating dock, and neither may involve dredging or filling. [flsenate.gov]

Deck height is a design decision with two failure modes: too low floods at king tides, too high is awkward stepping into the boat at low water. Tide range and the boat's freeboard set the number.

There is no county-mandated dock elevation, but there is one for seawalls, and dock decks are typically set relative to the seawall cap. Broward's tidal flood barrier minimum is 5 feet NAVD88, with 4 feet allowed until 2035. [library.municode.com]

If you plan to raise the seawall later, say so at dock design. A dock built to today's cap can end up a step below tomorrow's.

Electric shock drowning happens when current leaks into the water from a dock or boat and paralyzes a swimmer. NFPA's guidance: GFCI protection on dock circuits, inspection by a qualified electrician, and never swimming near a dock that has power. [nfpa.org]

Article 555 of the National Electrical Code requires ground-fault protection for receptacles at docks and marinas, and recent code cycles have tightened it further. [iaeimagazine.org]

On a rebuild, treat the lift motor circuit, dock lights and shore-power pedestal as one job for a licensed electrician, with the panel disconnect where you can reach it from shore.