Dock Rebuild - Part 1

We purchased a "Fixer-upper" on the Sun Coast of Florida to retire and permanently live in a warm clime. The property is located on a canal so it included an over water Dock shown above. The fixer-upper took most of the first year to make it habitable, our style and up to code; putting this entire project almost a year out as it's "Tide Dependent."
February is the month this coast has a low-low tide low enough to bear the bottom of the canal so, we had to do much pre-activity planning and materials acquisition. But the first step was an inspection to ascertain the extent of the repairs required.
Top, Deck view of Dock shows no problems
The top side of the Dock showed no problems, but the underside, the structure was a real safety issue.
The structure was eaten away by Marine Borers
The unsafe condition beneath the Dock pointed to a complete rebuild as the structure was weak from years of neglect and the poor design that permitted salty water to constantly contact the wood at high tide.
We made a sketch of the new Dock configuration, a tide dependent schedule and a work plan so that we would be well organized and, above all, maximize our "dry bottom" work time.
A Piling repair sketch was also prepared so that the most important aspect of the rebuild could be done, one at a time, one per day, with the right materials and using a consistent, proper method.


We did all this planning because we were prepared to do a full blown "Permit Package" and submit it to the Municipal Authorities. As luck would have it, we found out that Dock repairs did not require a City Permit! This saved us money, time and the headaches involved with working the bureaucracy.
Demo is always a fun thing to do, except when you're over the water and tools find themselves going "deep six." Nevertheless, the Deck was tedious to remove but not difficult. The planks that were in excellent condition were set aside to serve as Joists; the one not suitable for this were later used to make Dock Hand Rails and Adirondack inspired chairs.
Once low-low water showed the bottom, a good view of the Pilings showed their deplorable condition. The damage done by the Marine Borer was extensive.
A close-up view photo shows the damage to the Piling and the start of "hydro-excavating" the periphery to slip the sleeve over it.
Sleeves for repairing the Pilings were prepared from 8" inside diameter PVC water distribution pipes bought at a local "construction graveyard." The "teeth" were cut into the bottom of the pipes to facilitate digging them into the soft bottom.


The sleeves are "hydro-excavated" around the periphery of the Piling using a garden hose to move the muddy material as they are "dug in" about 6 to 8 inches deep. The length is cavity dependent, i.e., the sleeve is cut to the height of the cavity created by the Marine Borer plus two to three inches over it. This is easier than thought as the cavities created by the Borer are all at the same height. The only contributing factor is bottom depth; the outer Pilings are all the same, longer, length whereas the Seawall bottom is shallower making for a shorter sleeve.
A repaired Piling shows the PVC sleeve filled with 5000psi concrete that is premixed with very small pebbles. The use of a fine filler in the cement is important as the space between the Piling and sleeve is very tight.


The cavity is filled slowly with a small scoop of mortar premixed in a plastic container of shoe box. You only mix what you need, no more no less. As the cement tops and overflows, poke the mix into the cavity with a metal rod, or a very long screwdriver, to eliminate voids.


Air pockets are detrimental to concrete and are a major cause of structural failure - so this is an important task. I strapped an orbital hand sander to the Piling and it worked well.
After all the Pilings are repaired using the sleeves and concrete; they're ready for the structure. Being tide dependent, these six Pilings took six days to complete, or, one Piling per day of hydro sleeving, cement filling and trueing to vertical.


Now the structure portion of the rebuild, partially tide dependent can begin.
The Beams that support the Joists run from Piling to Piling as shown. Slinging them into place took a bit of Egyptian/Greek engineering. We placed and secured a top support on top of the Pilings and using slings and a rope we were able to swing the Beams into position at the correct height. FYI, a correct height is where the high tide water will not touch the Beams.


Leveling six Beams on three planes was not difficult at all - just tedious. Using the water hose used to hydro-excavate the muddy bottom around the sleeves/Pilings, we were able to level all the Beams in a few hours. We also used a lead line to serve as a reference on the Outer Pilings to make the leveling go faster.
The Beams secured to the Pilings ready for Joists. In this photo we left one "sling" on the center Beam to show a side view of how they were used.
The Joists were cut to length from the usable planking saved from the old Dock deck. The Joists that did not meet the criteria were later turned into Hand Rails and Adirondack inspired chairs.
The Joists were secured to the Beams on 12 inch centers using 305 S/S 2 1/2 inch long screws. The crisscross pattern used to secure the Joists will insure that high winds will not lift the Joists and cause structural failure; a feature that was lost on the simple galvanized nail pattern used on the old Dock. All the fasteners used in the rebuild were 305 S/S and were in effect the most expensive single item purchased. In all, over 1000 S/S fasteners were exclusively used, including the assembly of the handrails and the Adirondack design inspired chairs.


End of Dock Rebuild Part 1. See Dock Rebuild Part 2 for conclusion.
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