Aluminum Floating Docks vs Wood and Plastic: Choosing a Material

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It is the first warm Saturday in May, and two neighbors on the same cove are putting their docks back in. One drags 4 x 8 ft aluminum sections down the lawn on a dolly and bolts them together in an afternoon. The other has a heavy wooden float that never came out, and spends the day replacing a few soft boards. Both docks float; they were simply built from different stuff. If you are pricing an aluminum floating dock, a wood floating dock or a plastic floating dock, the material decides the weight, how the dock handles salt and ice, what your permit office will accept and how much yearly work it asks of you. This guide covers the three main materials for rigid (non-inflatable) floating docks, the decking that goes on top, and the prices and warranties makers actually publish.

In short: aluminum frames are light, don’t rot and come apart for winter, which makes them the usual choice for DIY lake docks; most consumer kits are sold for fresh water. Wood is cheap and easy to work, but it is heavy, needs the right pressure treatment and regular upkeep, and some agencies restrict treated wood over water. Plastic (polyethylene) systems have no frame to maintain at all: the float is the deck. Whatever you choose, check your state’s rules on decking and flotation before you buy.

Frame, decking and floats: three separate choices

A traditional floating dock has three layers. The frame carries the load and holds everything together. The decking is what you walk on. The floats underneath provide the lift; we cover them in detail in our dock floats guide. Aluminum and wood are frame materials, and you can put several kinds of decking on either. Plastic modular docks are different: sections such as EZ Dock, Connect-A-Dock or Candock cubes are float, frame and deck in one piece. Still deciding between rigid and inflatable? Start with inflatable vs rigid floating docks.

Aluminum floating dock frames

Which aluminum, and why it matters

“Marine-grade aluminum” on a dock listing usually means a 6000-series extrusion. Patriot Docks says its floating frames are 6061-T6, and so does Wahoo for its CAT5 custom docks. Public bid specifications ask for the same family: a Hawaii state specification for a floating dock system at Lahaina Small Boat Harbor called for 6061-T6, 6005-T5 or 6063-T6 extrusions, with welding to the AWS D1.2 aluminum structural welding code. Aluminum does not rot and needs no paint, but it can corrode where it touches the wrong materials.

Welded or bolted frames

Consumer kits are mostly bolted or slotted together, so they ship flat and go together with hand tools. Patriot’s low-profile sections connect with hinges or hard connectors, and the maker recommends a hinge every 16 ft so the dock can flex with the water. PlayStar sells a frame kit that can be built as a stationary, roll-in or floating dock. Custom and commercial docks lean on welding: Wahoo describes an interlocking aluminum frame with MIG-welded gusset reinforcements and all-stainless fasteners. Bolted kits are easier to ship and reconfigure; welded frames have fewer joints to work loose.

Fresh water vs salt water

Most aluminum floating dock kits sold to homeowners in the US are pitched at lakes. Patriot’s Premium T dock is listed for “lakes, reservoirs, rivers, and other waterfronts,” with no mention of salt, and a generic cedar-and-aluminum kit on Amazon describes its frame for “freshwater environments.” Salt water is harder on metal, mostly where aluminum touches another metal or a wet material. The Hawaii harbor specification shows what a saltwater buyer asks for: dissimilar materials insulated from each other, a coat of bituminous paint wherever aluminum touches wet or pressure-treated wood, no crevices where salt water can collect, Type 316 stainless fasteners on fenders, and a minimum five-year warranty against pitting and corrosion of the aluminum. Viance, a wood preservative maker, likewise recommends Type 316 or better stainless hardware where there is salt. If you are on the coast, get the maker’s saltwater approval in writing; our ramps and hardware guide covers galvanized vs stainless parts.

Wood floating docks

A wood floating dock is the classic DIY build: a lumber frame, galvanized corner brackets and encapsulated floats bolted underneath. Hardware kits make it straightforward. Multinautic’s floating dock kit, for example, includes four foam-filled floats rated 750 lb each, 1/4 in hot-dip galvanized brackets and back plates, and is built with 2 x 6 or 2 x 8 boards that you buy yourself (it was listed as unavailable on Amazon when we checked). Dock Builders Supply, a Florida supplier, says most residential lumber docks typically weigh 10 to 15 lb per square foot, and every one of those pounds uses float capacity.

Pressure-treated lumber near water: the rules that matter

• Buy the right treatment level. North Carolina’s Office of the State Fire Marshal advises AWPA Use Category UC4C for wood submerged in fresh water, UC4B for wood above the high-water line that gets wet often, and UC5B for wood submerged in salt or brackish water. The category is printed on the lumber tag.
• Not CCA for a home dock. EPA says manufacturers stopped making CCA (arsenic-based) treated wood for homeowner uses in December 2003; it remains for uses such as pilings and poles.
• Some agencies say less treated wood. US Fish and Wildlife Service guidance tells its staff to use alternatives to treated wood wherever practicable, to use only wood treated to AWPA specifications near water, and never to use pentachlorophenol-treated wood in water or railroad ties in aquatic structures. In Oregon, an Extension answer reports that the Department of Fish and Wildlife recommends not using pressure-treated wood for residential docks, framing included.
• Washington: no treated decking. Washington’s dock rules for both fresh and salt water say a design should not use treated wood for decking; treated wood may be used for structural parts.
• Match the hardware. Viance recommends hot-dip galvanized fasteners (ASTM A153) and connectors (ASTM A653, G185) as a minimum, stainless for very wet spots, 316 stainless for salt, and not mixing metals. Brush preservative onto every cut end and drilled hole.

Cedar and other naturally durable woods

Cedar is the usual untreated choice, especially for decking. A paper from FPInnovations notes that western redcedar heartwood is classed as “resistant to decay” in the USDA Forest Products Laboratory’s Wood Handbook, while also pointing out that decay resistance varies within and between trees. Only the heartwood earns that rating. Cedar deck panels on an aluminum frame give you the look of wood without a wooden frame.

Maintenance and lifespan

Check soft boards, loose bolts, rusty brackets and low floats every spring. We found no published lifespan for a homeowner’s wood floating dock. For scale, Bellingham Marine, a commercial marina builder, lists 20+ years for its timber floating dock system and 30+ years for its aluminum-frame system; those are engineered marina products, not DIY kits.

Plastic floating docks

Plastic floating docks come in two forms. The first is the modular system, where molded polyethylene sections are the whole dock. EZ Dock sections are UV-resistant virgin polyethylene (its 60 x 60 in section is rated 1,500 lb). Connect-A-Dock sections are 60 x 45 in, rated 690 lb each in the 1000 Series, and the maker says they resist oil, gas and salt water, with stainless or non-corrosive anchoring recommended in salt. Candock’s HDPE cubes are 19 x 19 x 14 in and hold only air. No boards to replace, no frame to corrode; see modular docks.

The second form is the polyethylene shell: floats, or float-and-deck units like Wave Armor’s sections, which pair a top deck with a foam-filled bottom float. The downsides: a plain look and trouble with ice. Connect-A-Dock says freezing will not harm its docks, but it recommends winter removal where ice shifts, and Candock says its cubes are not guaranteed against ice breakage, which it attributes mostly to moving ice in the spring thaw.

Decking on an aluminum frame

One reason aluminum frames are popular is that the decking is a separate choice, often in drop-in panels:

• Wood or cedar. The warmest look; Patriot and Dam Docks both offer cedar panels. Needs the same care as any wood.
• Composite. Trex says its decking is “100% submersible” and markets it for docks and marinas, but its dock page points only to limited residential warranties and warns it gets hot in direct sun, especially darker colors.
• Aluminum. Patriot’s 4 x 4 ft aluminum panel weighs about 25 lb, has a ribbed, textured surface and a powder-coated finish the maker says stays cooler than wood or composite.
• Poly or resin. Patriot’s polypropylene panels have internal aluminum slats; PlayStar’s kits use a resin top.
• Grated, light-penetrating decking. Panels full of openings that let sunlight through to the water. Thru-Flow, for example, makes fiberglass-reinforced polypropylene panels that its dealer says allow 43% sunlight penetration.

Why some states require grated decking

A solid dock shades the bottom, and shade harms the aquatic plants and young fish that live there. Washington is the clearest example we found. Its rules for residential docks in fresh water (WAC 220-660-140) and salt water (WAC 220-660-380) require at least 30% of the deck to be functional grating on a float 6 ft wide or narrower, and at least 50% on a float wider than 6 ft and up to 8 ft. The grating itself must be at least 60% open. In fresh water, flotation must sit under the solid part of the deck only, and if you grate more than the minimum, the open area can drop to 40%. Washington also requires foam flotation to be fully enclosed in a shell. Other states have their own rules, so check our permits and local rules guide and ask your permit office before choosing decking.

Aluminum vs wood vs plastic floating docks compared

	Aluminum frame	Wood frame	Plastic modular
Weight	Light: a Patriot 4 x 8 ft frame weighs 60 lb	Heavy: typically 10 to 15 lb per sq ft (Dock Builders Supply)	Sections are self-floating; no separate frame
Rot and rust	No rot; corrosion risk where metals mix, worst in salt	Rots without the right treatment; steel brackets can rust	No rot or rust
Salt water	Most consumer kits are sold for fresh water; ask the maker	Needs UC5B treatment where submerged; 316 stainless hardware	Connect-A-Dock: resists salt water
Decking	Wood, cedar, composite, aluminum, poly or grating	Usually wood or composite boards	Molded plastic surface
Seasonal removal	Easy: sections unbolt	Hard: usually left in or hauled whole	Easy to moderate: sections uncouple
Upkeep	Check bolts and fittings	Boards, finish, cut ends, brackets	Wash; check couplers

Weight and seasonal removal

Where lakes freeze, the material often decides whether the dock comes out at all. Barr Plastics lists shipping weights for its aluminum floating dock kits: 446 lb for an 8 x 16 ft section without decking and 695 lb with decking. PlayStar lists 266 lb for its 4 x 10 ft aluminum floating kit with resin top and three floats. Both come apart into sections for the trip up the bank. A wood float is usually one piece. Washington’s freshwater rule adds a detail many owners miss: floats removed for the season must be stored on upland ground, not on the beach. For the steps, see floating dock installation.

What floating docks cost, by material

These are prices on retailer and maker pages when checked in October 2026. They change often and rarely include shipping, anchoring or installation.

Product	Material	Price seen
PlayStar aluminum frame kit (frame only, no floats or deck)	Aluminum	$575.00, Amazon
Patriot Docks low-profile 4 x 8 ft floating section, two floats	Aluminum frame, poly or aluminum deck	$1,355.48 (poly) or $1,450.56 (aluminum) plus $139.99 shipping, Walmart
PlayStar 4 x 10 ft aluminum floating dock kit, resin top	Aluminum, resin	$1,779.21, Amazon
PlayStar Premium 4 x 10 ft floating dock, resin top and sidewalls	Aluminum, resin	$2,138.70, Amazon
Wave Armor dock sections	Polyethylene	$950 (30 x 60 in) to $2,950 (80 x 120 in), maker
Connect-A-Dock 20 ft straight kit	Polyethylene	$4,878.00, Amazon
Patriot Docks Premium “T” floating dock	Aluminum, aluminum deck	$8,588.59 sale price, Wholesale Marine

Some makers publish no prices at all: EZ Dock quotes through dealers, Barr Plastics quotes its aluminum kits, and Wahoo prices each custom dock by region. For a wood dock, the kit is only the hardware; HomeAdvisor puts floating docks at $15 to $35 per square foot including materials and labor. More in floating dock cost and floating dock kits vs inflatable docks.

Warranties, as makers state them

• Patriot Docks: limited lifetime warranty, per its Amazon listing.
• PlayStar: 15 years on the Premium floating dock (listing text); the standard kit’s listing shows 10 years.
• EZ Dock: 10-year limited warranty on dock sections; 1 year on hardware, anchoring and accessories.
• Candock: guaranteed for twenty years, but not against ice breakage.
• Taylor Made floats: 8-year flotation warranty.
• Thru-Flow decking: lifetime limited warranty, per its dealer.

Read the actual document before you buy, and ask whether salt water and ice are excluded.

Aluminum dock kits and parts on Amazon

These were in stock on Amazon when checked in October 2026. Dock pipes and anchoring are extra; ask the seller before using any of them in salt water.

Where inflatable docks fit

If your dock is mostly for swimming, lounging and launching paddleboards, and you want something you can deflate and store in a closet, an inflatable dock skips the material question entirely. It is not a permanent walkway for a boat. For the comparison, read building a floating dock vs buying inflatable, and for winter care, how to store an inflatable dock.

Floating dock material questions

Is an aluminum floating dock good in salt water?

It can be, but most consumer kits we found are sold for fresh water. Saltwater docks need insulated joints between aluminum and other metals or wet wood, 316 stainless fasteners and the maker’s written approval.

What wood should I use for a wood floating dock?

Pressure-treated lumber rated for its exposure: UC4C where it sits in fresh water, UC4B above the waterline, UC5B in salt or brackish water, per North Carolina’s State Fire Marshal. Cedar heartwood is a common untreated decking choice. Check local rules first: Washington says not to use treated wood for decking.

Are plastic floating docks worth it?

If you want almost no upkeep, often yes: there is no frame to rot or corrode. Expect a plain look, and plan to remove them where ice moves.

What is grated dock decking, and do I need it?

Decking with openings that let sunlight reach the water below. In Washington, residential floats must be 30% to 50% grated depending on width, with grating at least 60% open. Elsewhere it depends on your state and site.

Which floating dock material is lightest to take out for winter?

Aluminum frames with drop-in panels and plastic modular sections, because both come apart into pieces. A Patriot 4 x 8 ft aluminum frame weighs 60 lb before floats and decking.