SEAL-ONCE®

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OUTSTANDING PERFORMANCE

  • Excellent durability to weathering
  • Excellent longevity; prolongs the life of treated wood
  • Inhibits mold, mildew and fungi growth
  • Can be used on properly prepared interior and exterior wood surfaces
  • Semi-transparent stains add color without hiding wood grain
  • Protects horizontal surfaces up to 6 years and vertical surfaces up to 10 years
  • Safe for use around pets, plants, people and marine life
  • Water-based, odorless, and non-flammable
  • Non-toxic, ultra-low VOC and safe for the environment
  • Safe to use around fresh and saltwater
  • Easy soap & water cleanup
  • Made in the USA
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HIGH PERFORMANCE AND LONG-LASTING PENETRATING WOOD SEALER

SEAL-ONCE® is an eco-friendly, ultra-low VOC, water based stain and sealer for wood that offers high performance, long-lasting protection against water damage.

SEAL-ONCE® protects and stabilizes wood against water damage and decay for up to 10 years. It forms a flexible, breathable barrier that allows water vapor to escape and prevents warping and cupping.

The advanced technology of SEAL-ONCE® allows it to penetrate and bond to the cellular structure of the wood, forming a superior barrier below the surface to protect from the inside out.

Visit our Siding, Timbers, and Interior Application pages to experience our specialty manufactured products, all pre-finished with SEAL-ONCE®.

Common Uses: Decks, Railings, Shingles, Shake Roofs, Siding, Fences, Docks, Planters, Outdoor Furniture, Play Structures, Log Homes & Exposed Beams

For more information contact us or call (406) 215-4961

SEAL-ONCE® Technology
SEAL-ONCE® Trade Show Information
SEAL-ONCE® Water Repel Test
SEAL-ONCE® Featured on the Oxygen Network
SEAL-ONCE® Applied to Wood Decks Over Water

Product Stories

Independent Testing Results: Thermally Modified Southern Yellow Pine & Western Hemlock

Posted on: March 5, 2026

From Concept to Cabin: "Our PNW Home" x MTP - A Modern Minimalist Lake Cabin

Posted on: February 19, 2026

ranchwood™ Artisan Along the Susquehanna River

Posted on: February 4, 2026

Why Montana Timber Products?

natural wood

Embrace Authentic Beauty: We take pride in offering a stunning selection of sustainably farmed species, including Douglas Fir, Cedar, Southern Yellow Pine, and Hemlock ideal for architectural cladding and timbers. Elevate your space with the warmth and elegance of natural wood.

Custom milled

Tailored to Perfection: We can meet your exact design needs our product offerings range from custom siding and trim to large post and beam applications. MTP is the industry leader in specialty lumber.

prefinished

Ready for Immediate Use: Save on time and quality. Our durable, professional-grade Seal-Once finish, applied in our controlled facility, offers superior UV and water protection. Enjoy our premium finish options without the hassle of on-site finishing.

direct to customer

Simplified Purchasing Experience: 
We streamline the buying process and eliminate unnecessary middlemen. This direct relationship ensures that your specific needs are met with efficiency and care. Delivered directly to your jobsite.

Questions?
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Still unsure?
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