What’s Causing Carpenter Bee Holes in Your St. Louis Deck or Siding This Summer?

Carpenter bee holes seem to appear overnight on decks and siding across St. Louis. One week your railing looks fine. Then you spot a row of round holes drilled into the wood. These holes are not random. They follow a pattern tied to wood type, sun exposure, and the time of year. Homeowners in neighborhoods like Webster Groves and South County see this every summer. Ignoring the problem rarely makes it disappear. A closer look usually explains exactly why the holes keep showing up. Knowing the cause is the first step toward a lasting fix. Most homeowners just want a clear answer and a plan that works. If you want answers and a real solution, Omni Pest Solutions can help.

What Do Carpenter Bee Holes Actually Look Like?

Carpenter bee holes start small, but they rarely stay that way. Each one measures about the size of a dime, drilled into bare wood with a clean, round edge. The hole looks tidy at first glance, almost like it was drilled with a tool. Female bees create these entry points to reach a tunnel built for their eggs.

Look closely underneath deck railings, eaves, and fascia boards. You may also notice small piles of fine sawdust, called frass, scattered just below the entrance. Some homeowners hear a low buzzing sound near the wood before they ever see a hole. That sound usually means a bee is actively tunneling inside.

Signs Worth Checking For:

• Round, smooth-edged holes about a half-inch wide
• Sawdust piles directly beneath the hole
• Buzzing sounds coming from inside the wood
• Bees hovering near eaves, fascia, or railings
• Stains around the hole from bee activity

Call Omni Pest Solutions if you spot any of these signs around your home.

Why St. Louis Homes Attract Carpenter Bees

Carpenter bee holes show up most often on older, untreated wood. St. Louis has plenty of homes with cedar siding, redwood trim, and wooden decks, all prime targets. Many older homes near Tower Grove and Kirkwood still have original wood trim. That untreated wood is exactly what these bees look for each spring.

These bees prefer soft, bare wood over wood that’s painted or stained. Once a female finds a good spot, she often returns to the same area year after year. A single pair of bees can attract more bees to the same wood over time. Without treatment, the problem tends to grow each year.

Wood Most at Risk:

• Cedar and redwood siding
• Unpainted deck railings and posts
• Fascia boards under the roofline
• Wooden eaves and soffits
• Outdoor furniture left unfinished

Painting or staining exposed wood is a smart first step toward protection.

Why Summer Brings More Carpenter Bee Activity

Carpenter bee holes multiply fast once warm weather settles in. Spring mating season ends, and new tunnels appear through June, July, and August. By midsummer, holes that were barely visible in May often double in number. New bees emerge and search for fresh wood to claim.

St. Louis summers bring humidity and heat that soften exposed wood fibers. That makes tunneling easier for bees searching for a place to nest. Decks facing direct sun often see the heaviest activity. Shaded siding can still attract bees, just at a slower pace.

Peak Activity Months:

• June through August across the St. Louis region
• Warm, dry afternoons following rain
• Sunny sides of homes facing south or west
• Areas near gardens, trees, or wood piles
• Decks and patios used often in summer

Schedule an inspection now, before summer activity peaks.

The Hidden Damage Behind Every Carpenter Bee Hole

Carpenter bee holes look small from the outside, but the tunnels behind them tell a different story. A single bee can tunnel six inches or more into solid wood. What looks like a minor cosmetic issue often hides a much bigger problem. That tunnel can branch off in several directions inside the wood.

Year after year, bees return and extend the same tunnels further. Woodpeckers often follow, pecking at the wood to reach the larvae inside, which causes even more damage. Picture a woodpecker tapping away at your fascia board early in the morning. That noise is often a sign that carpenter bees are already inside.

Long-Term Risks to Watch:

• Weakened deck railings and support posts
• Structural damage to fascia and trim
• Woodpecker holes that worsen existing damage
• Repeated nesting in the same tunnels
• Costly repairs if left untreated for years

Left alone, the damage only gets worse.

Why DIY Treatments Rarely Work

Many homeowners try to plug carpenter bee holes with caulk or wood filler. This stops the bee inside, but it does nothing for the tunnel network already built. A plugged hole still has bees working somewhere nearby, often just out of sight. The tunnel network stays active even after the entrance looks sealed.

Store-bought sprays often miss bees tucked deep inside the wood. Without the right approach, the same holes reappear within weeks. Climbing a ladder to treat eaves or rooflines also carries real risk. A professional has the tools and training to handle the job safely.

Common DIY Mistakes:

• Sealing holes without treating the tunnel
• Using sprays that do not reach deep tunnels
• Painting over active holes without removing bees
• Ignoring nearby nests in eaves or fascia
• Ladder work on steep or unstable rooflines

A professional approach saves time and protects your home.

How Omni Pest Solutions Stops Carpenter Bees for Good

Omni Pest Solutions uses Integrated Pest Management to treat carpenter bee holes at the source. That means locating every tunnel, not just the holes you can see. Our technicians inspect siding, railings, eaves, and fascia for active and past damage. Nothing gets missed, including holes tucked into hard-to-reach corners.

Our team treats existing tunnels, then seals each entry point properly. Every visit comes backed by our 100% satisfaction guarantee. We treat the issue without harsh chemicals that could affect your family or pets. You can trust the work because we stand behind it completely.

What Our Process Includes:

• Free, no-obligation inspection of affected areas
• Targeted treatment of active tunnels
• Safe sealing of entry holes
• Follow-up visits if activity returns
• Same-day service in many cases

Our team gets the job done right the first time.

Protecting Your Deck and Siding After Treatment

Once carpenter bee holes are treated and sealed, prevention becomes the priority. Painted or stained wood is far less appealing to future bees. A fresh coat of paint or stain also protects against sun and rain damage. This simple step keeps wood less inviting to future bees.

Check exposed wood each spring before bees become active again. Small touch-ups now can save you from bigger headaches later in the summer! A quick walk around your home each spring catches problems early. That small habit can save you money down the road.

Easy Maintenance Habits:

• Repaint or restain wood every few years
• Inspect railings and eaves each spring
• Fill old holes only after full treatment
• Trim plants away from wooden surfaces
• Schedule a yearly inspection for peace of mind

A little upkeep goes a long way toward prevention.

Stop Carpenter Bee Holes Before They Spread This Summer

Carpenter bee holes never fix themselves, and waiting only gives bees more time to tunnel. Omni Pest Solutions has served the St. Louis area with honest, effective pest control for years. Our team offers free, no-obligation estimates and a 100% satisfaction guarantee on every visit. We handle everything from a single hole on a back deck to a full siding inspection. Carpenter bees rarely choose a different home once they settle in. Acting early keeps small holes from turning into bigger repairs. Our friendly team is ready to answer your questions anytime. You deserve a deck and siding that last for years to come. Don’t wait until the damage spreads further across your home. Call us today, and let’s get your deck and siding protected before bee season peaks!

We're prompt, professional, and parents too – with highly trained, trustworthy teams that always put your family's safety first, before, during, and after every service.