Here's What Matters: Your dock’s total weight = dead load (frame, decking, and hardware) + live load (people, furniture, and gear).
Dead load is the permanent structure — what your dock always weighs.
Live load is the temporary stuff — everything and everyone you add on top.
Add both together to find your total dock weight, then divide by the number of floats to see how much weight each float must support. Always plan for your maximum live load, and always round up!
Before you pick your dock floats or start framing, one of the most important steps in the design process is understanding your total dock weight. This determines how much buoyancy you’ll need and helps ensure your dock floats safely and evenly in the water. Let’s break this down into two main categories: dead load and live load.
Dead Load: Your Dock’s Built-In Weight
Your dead load is the total weight of your dock’s permanent structure. This includes:
- Frame: The lumber or metal used to build your dock’s skeleton.
- Decking: Wood, composite, or aluminum planks that make up your walking surface.
- Hardware: Bolts, brackets, corner pieces, and floats themselves.
Essentially, it’s the weight that never changes once the dock is built. For example, a standard 12'x12' dock with treated lumber and four floats might weigh between 800–1,100 lbs before adding anything else.
IMPORTANT NOTE: This also includes any permanent fixtures you're adding, such as handrails, hanging lights, etc. Those structures can add up!
Live Load: The Ever-Changing Weight
Your live load is everything that isn’t a permanent part of your dock — the temporary weight that gets added and removed. Think:
- People: Every person adds an average of 200 lbs.
- Furniture: Chairs, tables, or loungers can easily add several hundred pounds.
- Accessories: Grills, coolers, planters, or even a small watercraft.
You’ll want to design for maximum possible weight, not just your usual day-to-day use. Imagine a full dock party — that’s your true test. If you underestimate your live load, your dock will sit lower than expected in the water.
Why Both Matter
When you add your dead load and live load together, you get your total dock weight — the number that determines how many floats you need and what size they should be.
For example:
- Dead load: 900 lbs (frame, decking, hardware)
- Live load: 1,600 lbs (people + furniture)
- Total dock weight: 2,500 lbs
If you’re using five floats, each needs to support about 500 lbs. From there, check your buoyancy chart to find floats that maintain your desired freeboard height — typically 6” for a swimming / fishing dock or 10” freeboard for boat docks or if more clearance above the water is desired.
Quick Tip
Always round up when calculating total weight — it’s better to have a little extra buoyancy than to end up with a soggy dock when guests arrive.
This can sound intimidating to builders and non builders alike, but fear not! We are ready to help explain all of this more thoroughly to you, and we also have predesigned kits, that are pre-sized based on clearly stated freeboard, deadweight, and live load parameters.
Check out our DIY Dock Kits, or contact us to help design the perfect kit for your needs!
If you still want to figure it out yourself, but have some other questions, you can check out our DIY Dock Builders Guide for some more information.
Your dock should float level, solid, and safe — every time you step on it.