Sansin Impel Boron Rods

Internal Wood Preservative Rods for Long-Term Decay and Insect Protection

Sansin Impel Boron Rods are highly concentrated, solid borate preservative inserts designed to protect logs, timbers, and other wood structures from internal decay and insect attack. Inserted into pre-drilled holes in high-risk areas, these rods offer deep, slow-release protection against fungi and wood-destroying insects—even in moisture-rich environments. Ideal for both preventive and remedial treatment, Impel Rods activate only when needed and continue working long-term to safeguard wood from the inside out.

What Makes Impel Boron Rods Unique?

Impel Rods remain dormant until the surrounding wood reaches about 25% moisture content—the threshold where rot typically begins. Upon activation, the rods slowly diffuse boric acid throughout the surrounding wood using its natural vascular system. This process allows them to deliver effective, deep-penetrating protection where brush-on and spray treatments can’t reach. Approved by the EPA and recognized as environmentally responsible, Impel Rods are a proven, low-cost solution for extending the life of log and timber structures.

Key Benefits

• Long-lasting internal decay protection
• Activates only when moisture is present
• Delivers boric acid through wood’s natural pathways
• Effective against fungi and many wood-boring insects
• Ideal for use in new construction or existing structures
• Environmentally responsible and EPA approved

Where to Use

• Log homes and timber frame structures
• Base logs and butt & pass corners
• Decks, posts, beams, and foundation wood
• Window and door frames, fascia, and soffits
• Roof trim, attic supports, and crawl spaces

Application Notes

Surface Preparation Requirements

• Inspect wood for decay or high moisture areas before application
• Drill holes approximately 1/16″ larger than the rod for snug fit
• Insert rods perpendicular to the grain for best diffusion

Application

• Insert rods 6″ from log ends and at recommended spacing thereafter
• Seal with wood dowels, caulk, or wood filler after insertion
• Leave at least 1/8″ headspace inside the hole to allow for expansion
• Spacing depends on rod size, wood size, and decay risk—see sizing chart below
• Re-inspect plugs and treat again every 3–5 years or as needed

Coverage

Recommended application rate: 6 oz of boric acid equivalent per cubic foot of wood. Use manufacturer’s size and spacing guide for your specific rod dimensions and wood structure type.

Maintenance Required

Inspect treated areas every 3 to 5 years. Check plug status and replace rods if they are fully dissolved or if signs of decay reappear. Re-apply as necessary to maintain internal protection and always reseal treated holes to prevent moisture ingress.

Frequently Asked Questions

How do Impel Rods work?

They remain dormant until moisture is present, then slowly diffuse boric acid through the wood to stop decay and insect infestation.

Where should I install them?

Base logs, log ends, corners, fascia, beams, posts, and anywhere wood is exposed to water or at high risk of decay.

How often do they need to be replaced?

Inspect every 3 to 5 years and replace if rods have dissolved or if high moisture persists.

Are they safe for people and pets?

Yes. Boric acid is highly toxic to fungi and insects but has low toxicity to mammals when used as directed.

Can I use Impel Rods preventively?

Yes, they are ideal for preventing decay in new log homes, decks, and timber frames.

Do I need to seal the holes after installation?

Yes, use wood dowels, caulk, or filler to seal the holes and keep moisture out while allowing vapor to diffuse.

Do they activate without moisture?

No, they only activate when the wood reaches around 25% moisture content, minimizing unnecessary release.

Can I install them in vertical or horizontal wood?

Yes. Use appropriate patterns and depths depending on grain direction and log dimensions.

What sizes are available?

Impel Rods come in multiple diameters and lengths to suit dimensional lumber, round logs, and structural timbers.

Are they compatible with stains or sealants?

Yes. Seal over entry points using approved stains or water repellents for best results.

Downloads

• 📎Sansin Impel Boron Rods Product Data Sheet (PDF)
• 📎Sansin Impel Boron Rods Safety Data Sheet (PDF)