Holes in wood

Measure the hole and look at what’s below it: that tells you which wood-borer you have. Perfectly round 1/2-inch holes are carpenter bees, tiny shot holes with flour-fine powder are powderpost beetles, hard pellets are drywood termites, and shavings with insect parts are carpenter ants. The one thing to do: clean up the debris and check a week later for fresh material.

This page matches holes and debris to their likely source and says how to confirm activity. It rests on University of Kentucky guidance; structural damage needs a licensed inspector.

What’s Making Holes in My Wood? Hole Plus Debris

A carpenter bee below the clean, round hole it drilled into wood siding. Photo: Ahmedtahrir (CC BY-SA 4.0), via Wikimedia Commons.

Carpenter Bees: Perfectly Round Holes in Bare Wood

Carpenter bees bore into unpainted or weathered softwood such as fascia boards, decks and railings, often on the surface or the underside of a board. Coarse sawdust and yellow stains collect below the entrance.

Main clue: a perfectly round hole about 1/2 inch across, with coarse sawdust below it.

Termite Damage vs. Carpenter Ant Damage: Mud or Shavings

Carpenter ants chew smooth, clean galleries and push the shavings out, leaving coarse “sawdust” piles. Subterranean termites eat the wood itself and leave tunnels lined with soil or mud, with no sawdust outside (University of Kentucky). Drywood termites leave pellets instead of sawdust. Carpenter ant galleries also usually start in wet or decayed wood.

Main clue: coarse shavings with insect parts mean carpenter ants; mud-lined tunnels and no sawdust mean subterranean termites; piles of hard, six-sided pellets mean drywood termites.

Powderpost Beetles: Flour-Like Powder and Shot Holes

The University of Kentucky calls powderpost beetles second only to termites in damaging dry, seasoned wood. Infestations are usually found by the flour-like powder and small round shot holes. Light-colored fresh powder and new holes mean the beetles are still active.

Main clue: flour-like powder below tiny round shot holes, 1/32 to 1/8 inch across.

Old House Borer: Oval Holes in Softwood

Old house borers attack only softwoods like pine, fir and spruce, not hardwoods. Larvae tunnel for years and then cut an oval exit hole, according to the University of Kentucky. A faint ticking or rasping sound in framing can be larvae feeding.

Main clue: oval holes about 1/4 to 3/8 inch in pine or other softwood framing, with fine powder packed in the tunnels.

How to Confirm Activity

1. Sweep up the powder, pellets or sawdust, then check a week later; fresh material means activity.
2. Probe the wood around the holes with a screwdriver; soft, hollow wood shows how far damage goes.
3. Watch for winged insects near windows in spring, and for mud tubes on foundations.
4. Book a licensed inspector for termites or widespread beetle damage.

What to Do Next: Bees and Ants DIY, Termites to a Pro

Carpenter bee holes can be plugged and painted, as the carpenter bee page explains. Termites and widespread beetle damage need a licensed professional; start with the subterranean termite page to know what you’re dealing with.