16x16 Floating Dock Using 55-Gallon Barrels

Step 1: Cut and Assemble the Outer Frame

Cut, seal and lag-bolt 2x12 perimeter boards and 6x6 corner blocks into a square 192 in x 192 in outer frame.

Watch this step (3:06)

Parts in this step: (A) Outer frame end cap, (B) Outer frame side skirt, (C) Corner reinforcement block

You'll need: Tractor with loader, Circular saw, Cordless drill/driver, Tape measure, Hammer, Bar clamps, Paintbrush, Pressure-treated lumber, Pressure-treated post, Water sealer, 16 penny nails, Lag screws

1. 1.1 Cut Frame Lumber and Corner Blocks
   • Cut two 2x12 outer frame end caps (A) to 192 in.
   • Cut two 2x12 outer frame side skirts (B) to 189 in.
   • Cut four 6x6 corner reinforcement blocks (C) to 11-1/4 in (estimated).
2. 1.2 Seal Cut Ends
   • Pour water sealer into a wide-mouth jar fitting your paintbrush.
   • Generously brush water sealer onto the cut ends of parts A, B and C.
   • Coat every new pressure-treated cut immediately to stop water wicking and rot.
3. 1.3 Assemble the Outer Frame
   • Set the 189 in side skirts (B) on scrap blocks by the shoreline.
   • Clamp a corner reinforcement block (C) flush inside each end of side skirts (B).
   • Tack corner blocks (C) flush with 16 penny nails.
   • Set the 192 in end caps (A) across the side skirt (B) ends.
   • Pre-drill and drive 1/2 in x 5 in lag screws through the frame into blocks (C).

Key measurements

• Outer end caps (A) length: 192 in (16 ft).
• Outer side skirts (B) length: 189 in (3 in under 16 ft).
• Outer perimeter: 192 in x 192 in square.

• Tip: Cut heavy boards at waist height on tractor forks or a loader bucket.
• Tip: Build on scrap blocks near the water to shorten moving distance.
• Heads up: Never skip sealing cut ends; bare end grain absorbs water and rots fast.

Before you move on: Measure both corner-to-corner diagonals and adjust the frame until they match.

Step 2: Install Joists and Blocking

Scab end caps, hang 2x10 joists with 22 in barrel openings, and add 2x10 cross-blocking.

Watch this step (5:38)

Parts in this step: (D) Inner ledger scab board, (E) Internal joist, (F) Joist cross-blocking

You'll need: Circular saw, Cordless drill/driver, Ratchet straps, Tape measure, Hammer, Sledgehammer, Paintbrush, Pressure-treated lumber, Water sealer, Joist hangers

1. 2.1 Install Joists
   • Cut two 178 in 2x10 inner ledger scab boards (D) and seal ends.
   • Fasten scab boards (D) inside end caps (A) between corner blocks (C).
   • Cut eight 2x10 internal joists (E) to fit (about 186 in) and seal ends.
   • Mount joist hangers and set joists (E) parallel to skirts (B) with 22 in clear openings.
   • Pull bowed runs tight to joists with 27 ft ratchet straps before fastening.
2. 2.2 Install Cross-Blocking
   • Cut 22 in 2x10 cross-blocking (F) (about 21 pieces) and seal ends.
   • Sledgehammer the 22 in cross-blocking (F) between joists (E) to form bays.
   • Screw the blocking so wet pressure-treated lumber cannot push joints apart.
   • Leave two extra 22 in channels open for adding barrels later if needed.

Key measurements

• Joist (E) clear opening: 22 in to hold 23 in barrels snugly.
• Joist cross-blocking (F) length: 22 in
• Inner scab board (D) length: 178 in (between 6x6 corner blocks).

• Tip: Double outer ledgers with 2x10 scab boards (D) so 3 in hanger nails do not poke through.
• Tip: Test-fit a 23 in barrel in the first 22 in bay before hanging other joists.
• Heads up: 22 in joist openings exceed the 16 in span rating of most composite decking, causing slight flex.

Before you move on: Ratchet-strap the frame diagonally until both diagonals match.

Step 3: Prepare and Seal the Barrels

Clean, prime, cement, and caulk bungs on twenty 55-gallon plastic drums until watertight.

Watch this step (8:59)

You'll need: Caulk gun, 55-gallon plastic drums, PVC Cleaner, PVC Primer, PVC Cement, Silicone Caulk

1. 3.1 Seal Barrel Bungs
   • Unscrew the bungs from all twenty 55-gallon plastic drums and check the rubber gaskets.
   • Swab PVC cleaner and purple PVC primer on barrel and bung threads.
   • Coat threads with PVC cement and screw every bung in tight.
   • Run 100% silicone caulk around the top of every sealed bung.

Key measurements

• Sealed flotation barrels: 20 drums (55-gallon each).

• Tip: Use an assembly line to clean, prime, cement, and caulk twenty barrels in one session.
• Tip: Seal barrels in moderate or cool weather so cooling air inside does not cave sides in.
• Heads up: PVC cement does not weld polyethylene plastic; rely on tight threads, intact gaskets, and caulk.

Before you move on: Check all 40 bungs on the 20 barrels are tight and ringed with silicone.

Step 4: Install Barrel Supports

Add 2x4 barrel support struts inside bays so narrow barrel ends cannot slip through.

Watch this step (10:42)

Parts in this step: (G) Barrel support strut

You'll need: Circular saw, Cordless drill/driver, Tape measure, Paintbrush, Pressure-treated lumber, Water sealer

1. 4.1 Cut and Install 2x4 Barrel Supports
   • Cut twenty 22 in barrel support struts (G) from 2x4 lumber.
   • Brush water sealer on cut ends of each 2x4 strut (G).
   • Fit a strut (G) between joists (E) at each barrel bay end.
   • Screw struts (G) into joists where non-ringed barrel ends rest.

Key measurements

• Barrel support strut (G) length: 22 in

• Tip: Set the 2x4 strut under the smooth, non-ringed barrel end; it narrows when temperatures drop.
• Heads up: Barrels sealed on a hot day contract when cool and can pop through unbraced 22 in bays.

Before you move on: Check all twenty bays have a screwed 2x4 strut at the non-ringed barrel end.

Step 5: Launch the Dock Frame

Lift the frame with two loader tractors, tuck twenty barrels into bays, and launch into the pond.

Watch this step (10:42)

You'll need: Tractor with loader, 55-gallon plastic drums

1. 5.1 Position Barrels and Lift Frame
   • Roll the twenty sealed 55-gallon drums to the shoreline launch area.
   • Rig chains to opposite frame sides using two tractor loaders.
   • Lift the frame and advance both tractors until the front edge overhangs water.
2. 5.2 Insert Barrels and Launch
   • Slide barrels under the front rows, bungs inward away from sunlight.
   • Rest each narrower non-ringed barrel end against its 2x4 barrel support strut (G).
   • Place one barrel in each braced bay until all twenty are in.
   • Push the frame into water while stuffing barrels into trailing bays.
   • Tie the floating frame to the bank before decking.

Key measurements

• Barrel layout: 20 barrels across bays, about 9,500 lb buoyancy
• Bare frame weight: about 2,000 lb before decking

• Tip: Wear water shoes in pond sediment when placing barrels underneath.
• Tip: Load front bays first so water carries the front weight while loading the rear.
• Heads up: Stay clear of lifted edges while tractors move the 2,000 lb frame.

Before you move on: Check all 20 barrels sit in their 22 in bays and float the frame level.

Step 6: Install Composite Decking

Moor to a shore platform; fasten 16 ft composite deck boards across joists with hidden clips.

Watch this step (12:48)

Parts in this step: (H) Composite deck board

You'll need: Cordless drill/driver, Composite decking boards, Hidden Deck Fasteners, Shims

1. 6.1 Create a Work Platform
   • Back the decking trailer to the shore and chock the tires.
   • Tie the dock frame tight to the trailer to prevent drifting.
   • Lay the 192 in composite deck boards (H) (about 34) across joists as a floor.
2. 6.2 Install the First Deck Board
   • Align starter clips along the far outer edge over every joist.
   • Anchor starter clips to the frame with the provided clip screws.
   • Slide the first composite deck board (H) groove into the starter clips.
3. 6.3 Install Subsequent Deck Boards
   • Set hidden T-clip fasteners into the first board's open groove at each joist.
   • Drive clip screws halfway to float, slide in the next board (H), and tighten the prior row.
   • Slip shims between low joists and deck boards (H) to keep the walking surface level.
   • Repeat until all composite deck boards (H) are locked down.

Key measurements

• Composite deck board (H) length: 192 in (16 ft, perpendicular to joists)
• Completed dock weight: about 4,000 lb with wet pressure-treated framing

• Tip: Spread deck boards across joists first for a solid floor that keeps tools out of water.
• Tip: Kneel on a folded towel; dark composite boards reach 128 to 137 degrees F in the sun.
• Heads up: Chock trailer wheels before tying the 4,000 lb dock to the trailer.

Before you move on: Walk the deck; check every hidden T-clip screw is tight and no high corner blocks lift boards.