Seal-Once - MARINE Premium Wood Sealer (5 Gallon)

In stock

MARINE is a premium non-toxic waterproofing dock sealer & deck stain. It deeply penetrates the surface to protect and stabilize wood in high-moisture locations. It is an Eco-friendly wood finish, with ultra-low VOCs, and is safe to use around pets, plants & people .

  • Special marine formulation for use on wood near open water
  • Recommended for wood boat docks, pool decks, walkways
  • Piers & outdoor furniture near ocean, lakes, ponds & rivers
  • Non-Hazardous to Aquatic Life

FREE SHIPPING on 5 gallon pails!         
5 Gallon Pails Manufactured in Clear Only...
Colors available in single gallon size here

1 Gallon - Purchase Here
As low as $319.98


  • Docks
  • Outdoor Furniture
  • Thermally Modified Wood
  • Swing Sets


  • Water-based, Ultra-Low VOC
  • Eco-friendly, Non-toxic, No Odor
  • Won't harm people, pets or plants
  • Penetrates below the surface
  • Creates flexible, breathable barrier
  • Helps resist mold, mildew & wood rot
  • Stabilizes wood from warping
  • Extends natural life of wood
  • Easy soap & water clean-up
  • Clear allows the wood to grey naturally

SEAL-ONCE® has been leading the innovation in the use of nanotechnology to create long-lasting, Eco-friendly wood sealers & tinted wood stains since 2005.   MARINE Premium wood sealer and dock stain is specifically formulated to provide the highest level of protection for wood structures, situated near open water.  Wood used on boat docks, decks, and retaining walls near rivers, lakes, ponds or the ocean is subjected to near constant moisture.  MARINE provides the highest level of protection in those environments.  It is a great investment to extend the useful life of wood subjected to these harsh marine conditions.

SEAL-ONCE® MARINE Premium Waterproofing Wood Sealer & Stain is designed to protect & stabilize marine wood against water damage, salt water spray & decay.  Unlike many top-coat sealers on the market today, it penetrates wood below the surface, coating the wood fibers at the cellular level, which creates a long-lasting, flexible, breathable barrier.  It provides long-lasting protection from the inside out.

Clear formula allows wood to age naturally without decay, morphing to a rich silver-gray over time. Seal-Once Marine, when tinted as a wood stain, gives added UV protection from sun rays. Prevents long-standing water accumulation for up to 10 years on vertical & up to 6 years on horizontal surfaces.

Marine Product Data Sheet
Marine Safety Data Sheet


  • All surfaces should be cleaned before sealing for best penetration and performance.
  • Wet the surface.
  • Clean the surface with a solution of 1 cup  SEAL-ONCE All Wood Cleaner to 1 gallon of water Apply this solution to the wood with a garden pump sprayer.
  • Let the solution sit for 15-20 minutes. Do not let the cleaner dry.  Keep it wet.
  • Power wash the cleaning solution from the wood. To prevent damaging the wood do not exceed 500psi.  Keep the nozzle 1-2 feet away from the surface.
  • Rinse thoroughly.
  • Test absorbency after cleaning by sprinkling water on surface. If the water does not readily penetrate the surface, stripping will be necessary to remove old coatings.
  • Let the surface dry 1-2 dry days before application of Seal-Once.

How to Apply:

  • Do not use if air or surface temperature is below 45°F/7.22°C or above 95°F/35°C.
  • Do not apply in rain or when rain is expected within 12-24 hours. For all stains (including Ready-Mixed), intermix gallons and stir to ensure color consistency.
  • DO NOT THIN. Mix well. Stir contents or shake thoroughly prior to use.
  • Test a small area to ensure acceptable appearance and penetration.
  • Apply first coat with a synthetic brush; pump-up garden sprayer; air-assisted; and/or airless sprayer. Use 15-17 tip and medium to coarse spray pattern. When spraying, always back brush for best results.
  • Second coat can be applied once first coat has penetrated but is still damp. Second coat must be applied within one hour of applying first coat.
  • For best results, apply in the shade and out of direct sunlight.
  • When applying in direct sunlight and wood surface is hot, spray with a mist of water and apply SEAL-ONCE MARINE immediately on dampened surface.
  • Apply to all surfaces. Apply SEAL ENDS ONCE® to wood ends.
  • Do not use with other waterproofing products.
  • Remove excess stain sitting or puddling on the surface. Back brush or use a rag to wipe away any runs, drips, or puddles that have not soaked in.

Dry Time/Clean-UP:

  • Allow approximately 2-3 hours for surface to dry, depending on temperature and humidity, before subjecting surface to light foot traffic.
  • Allow 12-24 hours for full cure, depending on temperature and humidity.
  • When recoating, apply as soon as previous coat has penetrated and surface is damp, not wet. Second coat must be applied within one hour of applying first coat.
  • Clean application equipment with warm soapy water.
  • Disposal: soap and water cleanup; no special disposal procedure needed.
  • Store above 32°F/0°C to protect from freezing.
  • Shelf life (unopened): 3 years

Shipping Details Free Ground Shipping of 5 Gallon Pails
Offering free ground shipping for 5 gallon pails of this product that is shipping to the Lower 48 United States. This FREE OFFER does not apply to Alaska, Hawaii, and the US Territories.

Shipping is provided by Fed-Ex Ground for single gallon purchases and many times ships the same business day if ordered before noon EST. Most always 1-3 business days shipping standard.

All gallon cans will have a protective plastic rings applied to the lid ring for shipping. Protective foam inserts top & bottom of box on single and 2-pack gallon purchases.
Manufacturer U-C Coatings
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