How to Build a Crib Dock (and What It Really Costs)

Crib docks are one of the most time-tested and solid dock foundations you can build. When done properly, a crib dock can last decades, handle changing water levels, and provide a rock-solid base for a beautiful deck on top. Below is a practical breakdown of how a crib dock is built, how the deck is installed, and what it costs when a professional does the work for you.

What Is a Crib Dock?

A crib dock is a wooden box-style foundation built from heavy lumber, placed in the water, and filled with stone. Once sunk and leveled, a deck is built directly on top of the crib, creating a permanent and extremely stable dock system.

Crib docks are especially popular in:

• Shallow to moderate water depths

• Areas with firm lake bottoms

• Shorelines where long-term durability is the priority

How to Build a Rock-Filled Crib

1. Building the Crib Frame

The crib itself is built on shore using pressure-treated lumber. Think of it as a large, open-bottom box.

Key elements include:

• Heavy-duty pressure-treated lumber

• Overlapping corners for strength

• Internal cross-bracing

• Threaded rod running through the crib to lock everything together

We use threaded rod intentionally. It keeps the crib tight over time, resists shifting during freeze/thaw cycles, and dramatically improves long-term structural integrity.

2. Placing the Crib

Once assembled, the crib is floated or carefully positioned into place using barges or winching equipment. Accuracy here is critical, as final positioning affects everything above it.

3. Filling with Stone

After placement, the crib is filled with clean rock. The added weight sinks the crib and locks it firmly to the lakebed. Proper stone placement ensures:

• Even settling

• Long-term stability

• Resistance to ice movement

Building the Deck on Top of the Crib

Once the crib is fully set and level, the deck is constructed directly on top.

Deck Construction Includes:

• Framing anchored securely to the crib

• Pressure-treated joists and beams

• Proper spacing for drainage and airflow

• Optional fascia, bumpers, and hardware

Because the crib foundation is immovable, the deck feels more like a permanent structure than a floating dock.

What Does a Crib Dock Cost?

Here’s a realistic look at professional installation pricing.

Crib Foundation Costs

• Small crib (4’ wide x 6’ long): starting as low as $1,200

  • Ideal for ramps, walkways, or shallow shore connections

• Larger crib (10’ x 10’): approximately $3,000

  • Common for main dock platforms or load-bearing sections

Decking Costs

• Deck installed on crib: $30 per square foot for pressure treated lumber

This includes professional framing, fastening, and installation using marine-appropriate materials.

Example: A 10’ x 10’ crib with a 160 sq. ft. deck:

• Crib: ~$3,000

• Deck: ~$4,800

• Total: ~$7,800 (before accessories or additional sections)

Crib Dock vs. Piles: When Does a Crib Make Sense?

While pile-supported docks are a great option in many situations, a crib dock is often the better choice when:

• Water is shallow or fluctuates seasonally

• The lake bottom is firm enough to support stone-filled cribs

• You want a solid, permanent-feeling dock with minimal movement

• Ice pressure is a concern and weight is your friend

Cribs rely on mass and gravity, not penetration, which makes them ideal in areas where piles cannot be driven or permitted.

Why Choose a Professionally Built Crib Dock?

While crib docks look simple, getting them right takes experience. Professional installation ensures:

• Proper leveling and placement

• Correct stone volume and distribution

• Secure fastening using threaded rod

• Long-term resistance to movement and ice

A poorly built crib can shift, twist, or settle unevenly. A well-built one becomes part of the shoreline.

Frequently Asked Questions

Do crib docks require permits?

In most areas, yes. Requirements vary by municipality and lake authority. We always recommend confirming local regulations before construction.

How long does a crib dock last?

When built with quality materials, proper stone fill, and threaded rod reinforcement, a crib dock can last decades.

How does a crib dock handle ice?

Because of their weight and low profile, crib docks tend to resist ice movement better than lighter systems. Proper placement and rock volume are key.

Can a crib dock be expanded later?

Yes. Additional cribs, ramps, or floating sections can often be added as needs change.

Final Thoughts

Crib docks are not the cheapest option upfront, but they are often the Crib docks are not always the lowest upfront cost, but they are one of the most durable, stable, and permanent alternatives to helical piles. In locations where piles are impractical, restricted, or simply not the right fit, cribs provide a proven foundation that relies on weight and mass rather than penetration.

When built correctly, they offer decades of service with minimal maintenance.

If you’re looking for a dock that feels solid underfoot and performs like a permanent structure, a properly built crib dock is an excellent alternative to helical piles.