Most commercial floating docks are built from one of three materials: concrete, aluminum or timber. Each can be the right answer. The choice depends on how exposed the site is, which boats you berth, how long you need the dock to last and how much maintenance you want to take on. This guide compares the three, using Bellingham Marine’s own dock systems as examples.
The short answer
Choose concrete when you want the longest service life, the most stable walking surface and the least maintenance. Choose an aluminum frame dock when you want a clean, modern look in protected water. Choose timber when budget, a natural wood look or shallow, protected water matter most.
Floating dock materials compared
| Material | Bellingham Marine system | Construction | Published service life | Best suited to |
|---|---|---|---|---|
| Concrete | Unifloat® and Unibolt® | Concrete floats around a foam core, joined by walers and thru-rods (Unifloat®) or bolted connections (Unibolt®) | 50 to 60+ years | Commercial marinas that want durability and low maintenance |
| Aluminum | Unideck® Aluminum Frame | Aluminum frame with framed elastomeric block connections; composite or FRP grating deck | 30+ years | Clean, modern marinas |
| Timber | Unideck® Timber | Heavy-duty timber frame with a structural waler on roto-molded floats | 20+ years | Protected basins, small to mid-sized boats and shallow water |
Concrete floating docks
A concrete floating dock is the heaviest of the three, and that weight is its main advantage: a heavier dock moves less underfoot and in boat wake. Concrete is also fire and rot resistant, and utilities can be routed inside the float instead of hanging beneath the deck.
Bellingham Marine builds two concrete systems. Unifloat® modules are joined by structural walers and thru-rods, so sections can be replaced or reconfigured later. Unibolt® modules use a bolted connection whose bolts can be replaced without disconnecting the modules. Both are covered on our concrete floating docks page.
The trade-off is weight and handling. Concrete modules are cast in a plant and need heavier equipment to transport and install than a frame dock.
Aluminum frame floating docks
An aluminum frame dock carries the deck on a frame that sits on separate floats. It gives a marina a sleek, modern finish and accepts composite or light-penetrating FRP grating decking. Bellingham Marine’s Unideck® Aluminum Frame system uses framed elastomeric block connections and has a published service life of 30+ years.
Timber floating docks
Timber docks suit owners who prefer the natural look of wood and need an economical system. Bellingham Marine’s Unideck® Timber dock combines a heavy-duty timber frame with a structural waler and steel-reinforced connections. It is designed for protected basins, small to mid-sized boats and shallow water, including sites where the floats may ground at low tide. Decking options include southern yellow pine, composite, exotic hardwood and concrete panels.
The trade-off is lifespan: the published service life is 20+ years, shorter than concrete or aluminum.
What about steel?
Steel frame docks are a fourth option for inland and well-protected waters. The Unideck® Steel Frame system uses a galvanized steel truss frame on flotation tubs and has a published service life of 35+ years.
How to choose
- Exposure: the more wind, wave and wake the site sees, the stronger the case for a heavier concrete dock.
- Boat size: larger vessels put larger loads on the dock and its connections.
- Time horizon: compare the cost per year of service, not only the purchase price.
- Water depth: where floats may ground at low water, choose a system designed for it.
- Look and feel: concrete can be brushed, stamped or colored; frame docks accept timber, composite or grated decking.
Frequently asked questions
Which floating dock material lasts the longest?
Concrete. Bellingham Marine’s concrete dock systems have a published service life of 50 to 60+ years, compared with 30+ years for the aluminum frame system and 20+ years for the timber system.
Are concrete floating docks more stable than aluminum or timber docks?
A concrete floating dock is heavier than a frame dock of the same size, so it moves less underfoot and in boat wake.
Is a timber floating dock a good choice for a marina?
Yes, in the right place. Timber floating docks are designed for protected basins, small to mid-sized boats and shallow water, and they offer the natural look of wood.
Not sure which system fits your site? Talk to Bellingham Marine about your project.
