Seal Once Marine

Seal Once Marine Premium Wood Sealer

SEAL-ONCE® MARINE Premium Wood Sealer protects and stabilizes wood against water damage and decay. It uses proprietary nanotechnology to penetrate, coating the wood fibers at the cellular level. The advanced technology of MARINE allows it to form a superior barrier below the surface, protecting from the inside out.

MARINE allows wood to age naturally without decay, and can be used to preserve old or new wood, extending its natural life. It is non-film forming and will not alter the natural beauty of the wood. It is also completely eco-friendly and can be applied around or over open water, without harming marine life.

MARINE preserves the integrity of the wood by inhibiting warping, cupping, rot, mold, mildew and algae growth. MARINE forms a flexible breathable barrier that allows the wood to expand and contract, and for water vapor to escape. MARINE goes on milky white and dries clear. It is also available in semi-transparent tints.

Product Features


Non-toxic; will not harm pets, plants, people or marine life

Ultra-low VOC

Water based

Can be applied around or over fresh or salt water

Flexible, breathable barrier

Stabilizes & protects wood

Prevents warping, cupping, wood rot & decay

Resistant to salt water spray

Prevents mold, mildew & algae growth

Soap and water cleanup

Clear formula can be painted or stained after treatment

Tinted formula provides additional UV protection

Recommended Applications





Retaining walls

Outdoor furniture

Physical Characteristics

Color: Milky white liquid, dries clear
Flash Point: None
pH : 7+
Solvents: Water
lbs/gal : 8.5

Specific Gravity: 1.019
Viscosity: 50 cps
Application Temp. : 45°F/7.22°C* – 95°F/35°C
Odor: Nil
VOC Content : 25g/L**

*Do not apply when air or surface temperature is below 45°F/7.22°C or may fall below 45°F/7.22°C within 24 hours after application.

**VOC Content determined via EPA Method 24.

Available Colors


Light Brown



Bronze Cedar



Cape Cod Gray

Shale Gray

Battleship Gray


Packaging Sizes

1 Gallon Can | 5 Gallon Pail

Freight Class


Application Instructions


All surfaces should be cleaned before sealing for best penetration and performance. Remove all old coatings, dust, debris and loose material. Remove oil, grease, algae, grime, mill glaze and mold and mildew stains with appropriate cleaners. Recommend SEAL-ONCE All Wood Cleaner.

After cleaning, test absorbency of surface 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 SEAL-ONCE MARINE Premium Wood Sealer. Retest surface when dry.


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.

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.

Wood can be painted or stained as soon as it dries in approximately 2-3 hours, if SEAL-ONCE Semi-Transparent Tints are not being used.


Approximate coverage: 250-350 sq. ft./gallon per coat. Actual coverage will vary due to the porosity of the substrate.

Drying Time

Allow approximately 2-3 hours, depending on temperature and humidity, for surface to dry.

Allow 12-24 hours for full cure, depending on temperature and humidity.

When recoating, apply once previous coat has penetrated and surface is damp, not wet. Second coat must be applied within one hour of applying the first coat.

Cleanup & Storage

Clean all application equipment with warm soapy water.

Store above 32°F/0°C to protect from freezing.

Shelf life (unopened): 3 years.

Disposal: soap and water cleanup; no special disposal procedure needed.


Protect adjacent areas from overspray and runoff including windows and siding. Immediately remove overspray with soap and water.

Avoid breathing in spray. If inhaled, move to fresh air.

Avoid contact with eyes. If splashed into eyes, rinse with clean water for 15 minutes.

If skin irritation occurs, wash area with soap and water.

If accidentally ingested, immediately drink 2 glasses of water and contact a physician. Do not induce vomiting.

Do you need assistance in choosing the right wood and cement sealer for you?

We can help you from selecting the correct product you need in your project
from its professional engineering services.

Do you need assistance in choosing the right wood and cement sealer for you?

We can help you from selecting the correct product you need in your project
from its professional engineering services.