Dock, Seawall and Boat Lift Cleaning on the St. Johns River

If you are on the water in RiverTown, Julington Creek or anywhere along the St. Johns, you already know the dock is the dirtiest thing you own. It sits in humidity, it gets splashed, and half of it never sees sun.

What grows down there

• Algae and slime on decking, which is the slip hazard
• Black mildew in the grain of older pressure treated boards
• Barnacles and growth at and below the waterline on pilings and lifts
• Tannin bleed from the wood itself, which looks like staining but is the timber
• Salt and mineral crust on lift cables and hardware

Wood docks need restraint

This is where most dock cleaning goes wrong. A dock board is softer than it looks, especially after a few years in the sun. Hit it with a turbo nozzle and you will get it clean and leave it furred, splintered and far quicker to grow again, because you have opened up the grain.

The correct method is a cleaning solution that kills the growth, dwell time, and a wide fan at low pressure to lift it off. The wood should come up clean and still smooth.

Composite is not maintenance free

Composite decking resists rot, not algae. It grows the same green film in the same shaded spots. It cleans easily at low pressure, but it scars permanently under high pressure, and most composite warranties say so explicitly.

The runoff question

Cleaning a structure that sits directly over water is not the same as cleaning a driveway. What comes off the boards goes into the river. That shapes what can be used, and it is worth asking any contractor what they are putting on your dock and where they expect it to end up. On over water work we keep to solutions appropriate for the setting and we do not pressure dirty runoff straight down.

When to do it

Before the season you actually use it, and after the summer growth peak. Twice a year suits most docks here. Lifts and hardware are worth a look at the same time, because corrosion that is visible early is cheap and corrosion found late is a cable.

We work on docks, seawalls, lifts and waterfront decks across St. Johns County. If yours has got slick, call us before someone finds out the hard way.