Seal-Once - NANO Penetrating Wood Sealer (5 Gallon)

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NANO Penetrating Wood Sealer is a waterproof stain & finish that deeply penetrates the wood surface. It will protect and stabilize against water damage and decay. The water based formula uses our proprietary nanotechnology. It forms a flexible breathable barrier by coating the wood fibers at the cellular level.

  • Helps resist wood rot, wood decay, mold, mildew and fungi growth
  • Non-film forming clear formula allows wood to silver naturally and evenly
  • Eliminates wood warping & cupping caused by water intrusion

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1 Gallon - Purchase Here


  • Fences
  • Wood Siding
  • Log Homes
  • Shake Roofs
  • Thermally Modified Wood
  • Outdoor Furniture
  • Swing Sets
  • Pergola
  • Shakes
  • Decks


  • 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
  • UV barrier protects from sun rays
  • 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.  Our New & Improved NANO Penetrating Wood Sealer, deeply penetrates the surface of wood to protect and stabilize against water damage and decay.  Unlike many top-coat sealers that trap moisture below the surface, NANO creates a long-lasting, flexible, breathable barrier, that allows water vapor to escape & help prevent damage.  NANO is warranted to prevent water intrusion for up to 10 years on vertical & up to 6 years on horizontal surfaces.

SEAL-ONCE® NANO Waterproofing Wood Sealer & Stain is ideal for use on unfinished interior and exterior wood surfaces. The clear, non-film forming formula allows the wood to age naturally without decay, morphing to a rich silver-gray over time. It can also be used as a wood stain, when mixed with a full range of semi-transparent tints to enhance the appearance & provide additional UV protection from sun rays.

Material Safety Data Sheet
Product Data Sheet


  • 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.
  • Let the surface dry 1-2 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 NANO 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.
  • 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 the first coat.
  • Clean all application with warm soapy water.
  • Disposal: soap and water cleanup; no special disposal procedure needed.
  • Store unused product above 32°F/0°C to protect from freezing.
  • Shelf life (unopened): 3 years


Color Clear Matte
Shipping Details

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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