Dock Floats Explained: Foam-Filled, Air-Filled, and Modular Options

People researching how to build a dock with floats soon find out that the part nobody sees, the floats underneath, comes in a few main types that behave quite differently in the water.

Foam-filled floats are plastic shells, usually polyethylene, packed with foam. If the shell gets punctured, the foam still holds the dock up, which is a big reason they are common in Florida. The shell also protects the foam from sun, fuel and curious wildlife.

Air-filled floats are sealed hollow shells. They are light and easy to move around, but a crack can let water in, so they generally need more regular checking.

Modular cube floats snap together a bit like building blocks, forming the deck and the float in one piece. They are easy to reshape and suit jet skis, kayaks and swim platforms, although they tend to ride lower and feel bouncier than framed docks, which makes them less rigid for larger boats.

One thing most builders advise against is bare, uncoated foam. Over time it can crumble and shed pieces into the water.

The frame on top matters as much as the floats below. Aluminum frames are light and resist rust in salt water, and the floats bolt or strap onto the frame. Good hardware keeps everything from shifting when wakes roll through.

Choosing a float type usually comes down to how the dock will be used and what it needs to carry. Supreme Floating Docks builds aluminum, leisure, rowing and residential floating docks in South Florida, matching the float system to the site and the load, and all of its products are made in the USA.