How to Get Rid of Carpenter Ants: Complete DIY Pest Control Guide

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Carpenter ants are one of the most destructive household pests. While they don’t eat wood like termites, they tunnel through it to build nests, weakening walls, decks, and window frames over time.
If you’ve noticed large black ants crawling around your home, especially near wood or moisture, it’s time to take action before they cause costly structural damage.

This guide explains how to identify carpenter ants, where they nest, and the most effective DIY treatment strategies using professional-grade products that eliminate the colony — not just the ants you see.

What Are Carpenter Ants?

Carpenter ants are large ants — usually ¼ to ½ inch long, black or dark reddish-brown. They prefer damp or decaying wood but can also infest dry wood once they establish a colony.

Unlike termites, carpenter ants don’t eat wood — they excavate tunnels to create smooth galleries for nesting. This tunneling weakens wood structures and can lead to visible damage over time.

Carpenter Ants vs Termites: How to Tell the Difference

Feature Carpenter Ants Termites
Waist Shape Narrow, pinched waist Broad, straight waist
Antennae Bent (elbowed) Straight
Wings (Swarmers) Front wings longer than back All wings same length
Diet Do not eat wood Eat and digest wood
Frass (Debris) Sawdust-like wood shavings Mud tubes or pellets

If you see piles of fine sawdust under wood or hear faint rustling in walls, those are clear signs of carpenter ant activity.

Signs of a Carpenter Ant Infestation

 

  • Large black or reddish ants appearing indoors, especially at night
  • Piles of sawdust (frass) under wooden areas
  • Faint crackling sounds coming from walls or ceilings
  • Winged ants (swarmers) appearing in spring or summer
  • Hollow-sounding wood or soft spots near moisture-damaged areas

Carpenter ants are often most active after sunset, when foragers leave the nest to search for food.

Why You’re Not Just Killing Ants — You’re Targeting the Colony

 

When dealing with carpenter ants, spraying visible ants won’t solve the problem. The colony — and especially the queen — is hidden deep inside the wood or wall voids.
The key to permanent control is using non-repellent sprays, dusts, and baits that ants can carry back to the nest.

Here’s how it works:

  • Non-repellent sprays like Bifenthrin or Alpine WSG are undetectable, allowing ants to walk through and transfer the active ingredient to others — including the queen.
  • Ant baits (such as Advion or Optigard) are taken as food and shared throughout the colony.
  • Dusts and foams like Cimexa or D Fense Dust reach hidden galleries and wall voids, providing long-term residual control.

This colony-transfer effect ensures you eliminate the entire nest, not just surface activity.

🏠 How to Get Rid of Carpenter Ants Indoors

Step 1: Inspect and Locate Activity

Focus on areas with moisture and wood-to-soil contact:

  • Around window frames and door trim
  • Under sinks and in bathrooms
  • Attics, crawl spaces, and basements
  • Walls behind dishwashers or washing machines

Look for small piles of sawdust, hollow wood, or faint rustling — all indicators of a hidden nest.

Step 2: Apply Bait Gels

Use slow-acting ant baits to attract foragers and feed the colony.
Top choices include:

Apply pea-sized dots along trails, cracks, and entry points (especially near moisture). Allow the ants to feed and carry the bait back. Do not disturb them.

Step 3: Use Non-Repellent Sprays

After baiting, apply a non-repellent spray to high-traffic and entry areas:

  • Alpine WSG – water-soluble, odorless, and ideal for kitchens or living spaces.
  • Bifenthrin– strong residual protection around baseboards, wall voids, and foundations.

These sprays eliminate hidden ants through contact and transfer, providing long-term colony control.

⚠️ Avoid using repellents like Raid, vinegar, or bleach. These scatter ants and break the baiting cycle.

Step 4: Treat Wall Voids and Damaged Wood

If you suspect ants nesting inside walls or wooden beams:

  • Drill small access holes and apply Cimexa Dust or Bora-Care Foam directly into galleries.
  • Cimexa (silica dust) dries out insects on contact and remains active for months.
  • Bora-Care penetrates wood, killing existing ants and preventing reinfestation.

Be sure to vacuum any visible frass before treatment.

🌳 How to Get Rid of Carpenter Ants Outdoors

Outdoor control is essential since colonies often start in trees, stumps, or landscape timbers before moving indoors.

Step 1: Locate and Treat Nests

Inspect for:

  • Ant trails on trees, fences, or walls
  • Hollow or decaying logs
  • Moist wood near decks or siding

Treatment Plan:

  1. Spray the nest area with Taurus SC or Alpine WSG to allow for colony transfer.
  2. Then apply a granular bait such as:

These granules act as food sources ants carry back to the colony, ensuring full elimination.

Step 2: Perimeter and Yard Treatment

If you can’t locate the exact nest:

  • Spray a 3–5 ft barrier around the foundation using Taurus SC for long-lasting protection.
  • Apply Bifen LP Granules around mulch beds, tree bases, and driveways for residual coverage.

Reapply treatments every 2–3 months during active ant season (spring through fall).

đźš« Carpenter Ant Prevention Tips

Once you eliminate the colony, prevention keeps them from coming back:

  • Repair leaks and eliminate moisture sources.
  • Trim trees and shrubs that touch siding or rooflines.
  • Seal cracks and gaps around doors, windows, and foundation joints.
  • Store firewood off the ground and away from your home.
  • Inspect annually for signs of sawdust or large black ants.

🧰 Recommended Product Summary

Treatment Type Product Examples Best Use
Baits Advion Ant Gel, Optigard, Terro Ant Bait  Colony feeding and transfer
Non-Repellent Sprays Alpine WSG, Bifenthrin Indoor and outdoor contact and transfer kill
Dusts & Foams Cimexa, Bora-Care Wall voids, wooden galleries, attics
Granules Advance 375A, Niban, MotherEarth, Bifen LP Yard and perimeter protection
Prevention Caulk, moisture control, trimming vegetation Long-term exclusion

Carpenter ants are more than a nuisance — they’re a warning sign of hidden moisture or wood decay.
Eliminating them requires a colony-focused strategy, not just surface sprays.

By combining non-repellent sprays (Bifenthrin, Alpine WSG), baits (Advance 375A, Advion), and void treatments (Cimexa, Bora-Care), you’ll destroy the queen, collapse the colony, and protect your home for the long term.

👉 For complete step-by-step guidance and recommended products, visit HowToGetRidOfBugs.guide — your trusted resource for DIY pest control.

 

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