Boat lockers and storage compartments are wet environments. Rain, spray, splash, and condensation find their way into every hatch and locker. The question is what happens to that water once it gets in.
The default fix for most boaters is foam matting: cut a sheet to fit the locker floor, drop it in, and gear sits on something other than bare fiberglass or aluminum. It is a reasonable starting point, but foam and drainage tiles solve the moisture problem in opposite ways. Understanding the difference helps you choose the right approach for your compartments.
How foam matting handles boat locker moisture
Closed-cell foam matting is dense and does not absorb water easily on its own. The problem is the geometry: foam lies flat on the compartment floor, and water that enters the locker pools under and around it. Gear sits slightly elevated, but the foam stays in contact with the water below. In a closed compartment with limited airflow, the space stays damp between uses. The foam traps moisture against the fiberglass floor instead of draining it away, and anything stored on top sits in a humid, slow-drying environment.
Open-cell foam absorbs water directly and stays saturated. Both types create a surface that remains wet long after the boat is back at the dock, and mildew follows quickly in enclosed, low-airflow spaces. Foam also picks up odors from fish, diesel, and bilge water over time.
What drainage tiles do differently
Drainage tiles work on a different principle: elevate the gear, open the floor, and let water move through rather than pool underneath.
Each Dri-Dek 1'x1' tile stands on 284 flexible legs per square foot. That leg structure lifts stored gear 9/16 of an inch above the compartment floor. Water that enters the locker passes through the open tile surface and drains to the low point of the compartment rather than soaking what is stored above. Air circulates underneath the gear and dries the space between uses. This is the structural opposite of foam: foam creates a barrier that traps water, while drainage tiles create a path that moves it.
The Oxy-B1 vinyl the tiles are made from resists salt water, brine, oils, and detergents. UV stabilizers protect the material from sun exposure on open deck areas or in compartments that see daylight. Built-in antimicrobials in the vinyl inhibit mildew and odor growth on the tile surface itself, which matters in the enclosed, low-airflow spaces typical of marine lockers. The tiles are rated for continuous use from -30 degrees F to 167 degrees F, so temperature extremes aboard a stored or trailered boat present no issue.
Marine specs that matter
- Gear elevation: 9/16 inch above the compartment floor with open airflow underneath
- Material: Oxy-B1 PVC vinyl with UV stabilizers; resists salt water, brine, oils, and detergents
- Antimicrobial: Built-in additives inhibit mold, mildew, and bacteria in enclosed spaces
- Temperature range: -30 degrees F to 167 degrees F (ASTM D 746)
- Tensile strength: 2,750 PSI (ASTM D 412); elongation 348%
- Compression strength: Over 3,000 PSI; handles tools, equipment, and heavy gear without deforming
- Flame resistance: UL 94V-O passed
- Non-slip surface: Textured raised-grid drains water immediately; no standing water on top
- Sound dampening: The flexible vinyl absorbs impact; particularly noticeable when weights, tackle, or tools are dropped
Fitting tiles to compartment shapes
Boat compartments are rarely square. Anchor lockers have angled walls, cockpit lockers taper at the edges, and under-seat spaces have curved corners. Dri-Dek tiles trim with a utility knife or heavy scissors to follow any compartment profile. Most owners snap the tiles into the approximate shape, make a cardboard template of the locker floor, then trim to that outline. The snapped assembly lifts out as one piece for cleaning or inspection.
No tools or adhesives are needed. Tiles connect by snapping together and hold their position under stored gear. The liner lifts out when you need to clean the compartment or inspect the hull underneath. Nothing is glued or fastened to the boat.
Cleaning a lined locker
The liner comes out in one piece, hoses off, and drops back in. For lockers that accumulate salt buildup, fish residue, or organic material, a 2,000 to 3,000 PSI pressure washer on both the top and bottom surfaces removes the buildup. The non-porous vinyl surface absorbs no odors, so cleaning removes whatever has settled on it without the residual smell that foam retains.
"I put this at the bottom of a wet lazarette and it works wonderfully." -- Verified customer review
Common questions about foam vs. drainage in boat compartments
Does foam ever make sense in a boat locker?
Foam provides sound and impact protection in applications where moisture is not the primary concern. In a locker that collects water, foam traps that water against the floor and keeps the compartment wet. Drainage tiles address the water directly: they elevate gear, move water to the drain point, and let air circulate so the compartment dries. If moisture is the issue, the two approaches work in opposite directions.
Does salt water damage drainage tiles?
No. The Oxy-B1 vinyl resists salt water and brine as part of its chemical resistance specification. UV stabilizers protect against sun exposure. Dri-Dek is rated for continuous marine use from -30 degrees F to 167 degrees F and will not crack, fade, or degrade under normal marine conditions.
Will drainage tiles stop the mildew smell in my lockers?
They remove the conditions that cause it. Gear dries because air circulates beneath it instead of sitting in standing water. Built-in antimicrobials in the vinyl resist mildew growth on the tile surface. Combined, these reduce the sustained moisture and organic buildup that produce odor in closed lockers.
How do I figure out how many tiles to order?
Each tile covers one square foot. Measure the locker floor area in square feet and round up to account for trim. Tiles are available in 6-packs, 12-packs, 25-packs, and 50-packs. The 3'x4' Sheet covers 12 square feet and fits larger compartments; it trims just like individual tiles.
Can the liner stay in the locker all season?
Yes. The tiles are rated for continuous use and resist the temperature swings, moisture, and chemical exposure of a full marine season. Lift the liner out periodically to hose down the compartment floor, then drop it back in. The material does not degrade from prolonged exposure to the marine environment.
Dri-Dek availability and warranty
Dri-Dek has been made in the USA since 1977 and carries a 5-year warranty against defects in material and workmanship. It holds a 4.93-star rating across 121 customer reviews. Free samples are available, and orders often ship same day. See current pricing at the Dri-Dek product page.
For more on marine applications and compartment types, see the boat compartment drainage page. For material properties and chemical resistance detail, see the material properties FAQ. For common use-case questions, see the use cases FAQ.