Marine Construction: Docks, Pilings & Boat Lifts

Pilings do most of the work, so they get the most scrutiny. Marine-grade timber pilings for salt water are pressure-treated to 2.5 pounds of CCA per cubic foot (AWPA use category UC5B/UC5C). One large piling supplier reports 25 to 35 years for properly treated pilings on the Gulf Coast, and roughly five years or less for untreated wood in warm, high-salinity water. Those are the supplier's figures, not a promise. [americanpoleandtimber.com]

The enemy is not rot so much as marine borers. Shipworms are bivalve mollusks that tunnel through wood from the inside; UF/IFAS Extension notes burrows from seven inches to more than six feet long. The damage stays hidden until the piling necks at the waterline. [blogs.ifas.ufl.edu]

For decking, Florida boaters on The Hull Truth report pressure-treated pine checking and splitting within a year or two, while ipe and cypress hold up much longer. Composite and PVC boards need no sealing and hose clean, but owners flag heat on dark colors, slipperiness with dew and the need for tighter joist spacing. [thehulltruth.com]

If you are replacing a dock in the same footprint, Florida law lets you switch to different construction materials under the repair-and-replace exemption, which is how most wood-to-composite swaps are handled. [flsenate.gov]

Hardware should be stainless or hot-dip galvanized; plain zinc-plated fasteners do not last in the splash zone. Ask what fasteners, hangers and through-bolts are specified before you compare quotes.

Size the lift to the boat's wet weight, not the brochure dry weight. ShoreMaster's rule of thumb is dry weight, plus fuel tank gallons times six pounds, plus about 500 pounds for gear, batteries, coolers and people, then a 20 percent safety margin. If that lands between two models, size up: lifts are rated for their capacity and not a pound more, and they cannot be upgraded later. [shoremaster.com]

Hurricane Boat Lifts adds water weight (livewells, bilge, rain) to the same formula and recommends the higher end of a 10 to 20 percent margin in salt water. [hurricaneboatlifts.com]

Four-post cradle lifts carry the boat on bunks between pilings and suit most canals; elevator lifts mount to the seawall or pilings on one side and suit narrow canals or shallow water. PWC lifts are commonly in the 1,500 to 2,500 pound class. [mcidocks.com]

A lift is covered by the state single-family dock exemption up to 500 square feet (200 square feet in Outstanding Florida Waters). A lift added to an existing dock still needs its local approval; in Broward that is a county general license. [flsenate.gov]

Cables are the wear item. Look at them every time you use the lift, and replace on condition rather than on a date: fraying, a kink, a deformity or heavy corrosion anywhere on a cable. When one cable lets go the other three carry the load, which is why they are replaced as a set.

The cradle and elevator lift capacities we install are listed above. Tell us the boat, the fuel capacity and how you load it, and we size from there with the lift manufacturer.

A piling that wobbles has lost either its embedment (scour or storm uplift) or its cross-section (borers or rot at the waterline). Tightening the framing bolts will not fix it. A loose or leaning piling generally cannot be repaired in place; it needs to be supplemented, for example by driving a sister piling beside it and transferring the load, or replaced.

Where the wood below the mudline is still sound and the damage is at the waterline, a concrete-filled jacket is the middle option. We install the SnapJacket system without lifting the deck or removing the lift. When the piling has failed below the mudline, when the dock is being enlarged, or when you want concrete or composite pilings, we drive new ones.

Have pilings looked at on a regular interval, after any storm, and after a hard boat strike. Above water you can spot leaning, waterline necking, soft wood and loose hardware; below water a diver probes for borer tunnels and scour at the mudline.

Installing or repairing pilings on a private dock is itself an exempt activity under FDEP's rules, which keeps the state side of a piling job simple. [law.cornell.edu]

State: Florida Statute 403.813(1)(b) exempts a private recreational dock of 1,000 square feet or less of over-water area (500 square feet or less in Outstanding Florida Waters) if it sits on pilings or floats, involves no dredging or filling beyond setting the pilings, does not block navigation and is the only exempt dock along 65 feet of shoreline. [flsenate.gov]

FDEP lets homeowners self-certify these docks online with no fee, and the self-certification carries the federal authorization for docks, piers and other minor piling-supported structures. [floridadep.gov]

Riparian rules: structures and mooring pilings must sit at least 25 feet inside your riparian lines (10 feet for a marginal dock along the seawall), with exceptions for lots under 65 feet wide or with a neighbor's written consent, and a dock may extend no more than 25 percent of the waterway width. [law.cornell.edu]

County and city rules sit on top of the state exemption, and they are where most of the time goes. The county-by-county walk-through, including what each office asks for, is in our dock permit guide for South Florida.

• Miami-Dade: a DERM Class I Coastal Construction Permit is required before any work in, on, over or upon tidal waters or coastal wetlands, inside cities included. [miamidade.gov]
• Broward: an Environmental Resource General License covers dock repair or replacement not enlarged beyond 500 square feet of over-water area and boat lift installation; larger work needs a full Environmental Resource License. [broward.elaws.us]
• Palm Beach County: docks, lifts and boathouses are Type 8 Marine Structures building permits, and the application asks you to attest that every authority with jurisdiction over the water has approved the work. [discover.pbcgov.org]
• Manatee County: the Building Division issues a Waterfront Structure permit (building plans plus site plan or survey) through its online portal; much of Anna Maria Sound, Palma Sola Bay and Sarasota Bay is Outstanding Florida Waters, so the 500 square foot threshold applies there. [mymanatee.org]
• Cities go further: Fort Lauderdale caps mooring structures at 25 percent of the waterway width or 25 feet, whichever is less. [fortlauderdale.elaws.us]