• “It was child’s play to apply Seal-Once to our 1,200 sq/ft mahogany deck. Unlike previous sealers we used, I am sure it will be a long time before we need to reapply. We are sold on this eco-friendy product.” — Jeff Lavoie, NH Homeowner


Seal-Once™ Marine Waterproof Multi Surface Concentrate

industmarine5_1gallupto10newSeal-Once™ Advanced Marine Multi-Surface Waterproofer is a concentrated, waterbased formula designed for waterproofing wood, composite wood, concrete and masonry. Eco-friendly Seal-Once is designed to be diluted with clean water at a 1:1 ratio for easy application.

Uses: Docks, Piers, Retaining Walls, Ramps, Pavers, Brick, & Walkways, Stucco, Boardwalks, Railings, Fences and Green Concrete. Allow pressure-treated wood to age up to 3 to 6 months before applying Seal-Once.

CLEAR • No. 7814 • ONE U.S.GALLON / 3.79L
CLEAR • No. 8814 • FIVE U.S.GALLONS /18.92L

  • nhdesNon-toxic, Zero VOC’s, Safe for the Environment
  • Safe to Use Over Fresh and Saltwater.
  • Long-Lasting, Deep Penetrating Bond Protects Against Mold and Mildew
  • Paintable, Stainable, Breathable
  • Outperforms Other Sealers and Stains
  • UV Stable
  • Water-Based, Odorless, Non-Flammable, Non-Combustible, Will Not Burn Skin
  • Will Not Harm Fish, Plants, Animals or Humans
  • Helps Prevent Wood from Cracking, Splitting and Warping
  • Reduces Corrosion, Spalling and Cracks Caused by Moisture
  • Helps Protect Against De-icing Salts and Pool Chemicals
  • Clear Formula Will Not Discolor Surface
  • Semi-Transparent Tints Available
  • Non-Film Forming
  • Easy Soap & Water Clean Up

All surfaces should be cleaned before sealing for best penetration and performance of a coating. Remove algae, grime or mildew with Seal-Once™ cleaners. Pressure washing is recommended.

After cleaning, test absorbency of wood by sprinkling a few drops of water on the surface. If the water does not readily penetrate the surface, stripping will be necessary to remove old coatings prior to applying product. Retest surface after dry. (Sanding or removal of paint containing lead may be hazardous. Call 1-800-424-LEAD for details.)

  • Do not use if air or surface temperature is below 35°F.
  • Do not apply in rain or when rain is imminent.
  • Combine equal parts Seal-Once and clean water (1:1 ratio). Use a paint stick or jiffy mixer and mix for one minute. DO NOT THIN.
  • Apply two even coats wet on damp with a brush, pump-up garden sprayer, air-assisted and/or airless sprayer. Use medium to coarse spray pattern. Brush out any puddles.
  • For best results, apply in the shade and out of direct sunlight.
  • When applying in direct sunlight and surface is hot, spray with a mist of water and apply Seal-Once™ immediately on dampened surface.
  • Apply to all wood surfaces and ends.
  • Do not use with other waterproofing products.
  • On very porous, aged surfaces an additional third coat may be necessary.
  • Wood can be painted or stained within 24 hours after Seal-Once™ is applied. Use Seal-Once tints for best results.
  • Approximate coverage 200-300 square feet per gallon, per coat. Actual coverage will vary due to porosity of surface.


Wood/composite surfaces: Allow water to evaporate for 2-3 hours before subjecting to light foot traffic; allow 24-48 hours for full cure, depending on temperature and humidity.

Concrete/masonry surfaces: Allow to dry 1-2 hours depending on temperature and humidity.

When recoating, apply as soon as previous coat has penetrated the surface.

Clean equipment and brushes with warm, soapy water. Store unused product above 32°F, protect from freezing.


Seal-Once & Poly Blend treated surfaces can be cleaned with 1 gallon of warm water, 14 oz. bleach, and 1 oz. of dawn dish detergent. Apply cleaning solution with a sprayer and allow to rest for twenty to thirty minutes before rinsing with water using a garden hose with a nozzle. Use cleaning solution to remove airborne mold and mildew stains, dirt, grime, etc. on the surface. Seal-Once & Poly Blend will prevent and resist any water, mold, and mildew penetration. Do not use oxidizers, corrosives, or strippers on Seal-Once treated surfaces.

Surfaces can be recoated with Seal-Once or Poly Blend at any time. Seal-Once or Poly Blend may need to be reapplied for fading tint color, surface damage, or in heavily worn or high traffic areas, or in places where the surface may have undergone noticeable changes. Apply the recommended cleaning solution above. Apply Seal-Once or PolyBlend either clear or tinted, two coats wet on damp with a brush, stain pad, or sprayer. When reapplying in small areas lightly overlap onto areas previously treated with Seal-Once or Poly Blend.

Contains No Toxic or Hazardous Materials Seal-Once is a minor irritant to eyes, skin, inhalation and ingestion.
  • If splashed onto eyes, rinse with plenty of clean water for 15 minutes.
  • If inhalation irritate mucous membranes, move to fresh air.
  • If splashed onto skin, wash with soap and water.
  • If accidentally ingested, drink two glasses of water and refer to medical personnel. Do not induce vomiting.
Sanding or removal of paint containing lead may be hazardous. Call 1-800 424-LEAD for details. KEEP OUT OF REACH OF CHILDREN. Manufacturer’s responsibility is limited to the purchase price of this product.
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