Termite Inspection: Field Guide for Inspectors

Termite damage is one of those findings that changes the trajectory of a deal. A minor settlement crack gets negotiated. A furnace near end-of-life gets a price adjustment. But active termites or significant structural damage from past infestations — that stops buyers in their tracks and keeps them stopped until they understand the scope.

Your job during a termite inspection isn't to treat. It's to find evidence, document it accurately, assess the extent of visible damage, and make the right referral. Here's how experienced inspectors approach it, from exterior perimeter to crawl space floor joists.

What You're Actually Looking For

Termites don't announce themselves. The colony lives underground (subterranean) or inside the wood they're consuming (drywood). By the time damage is visible to the homeowner, the infestation has been active for months or years.

Your advantage as an inspector is knowing what to look for and where to look. Homeowners see a baseboard. You see the mud tube behind it.

Subterranean Termite Evidence

Subterranean termites are the most common and most destructive species in North America. They live in the soil and build mud tubes to reach wood above grade.

• Mud tubes. Pencil-width tubes made of soil, wood particles, and termite saliva. They run vertically from the ground up foundation walls, piers, or utility penetrations. This is the single most definitive sign of subterranean termite activity.
• Damaged wood. Subterranean termites eat along the grain, creating a layered or honeycomb pattern. The wood may look intact on the surface but sound hollow when tapped.
• Swarmers or wings. Piles of discarded wings near windows, doors, or light sources — especially in spring. Swarmers are reproductive termites that leave the colony to start new ones. Finding wings inside the house means they're coming from inside, not outside.
• Moisture and wood contact. Subterranean termites need moisture. Any wood-to-soil contact is an invitation — deck posts set directly in the ground, form boards left in place, wood siding extending below grade.

Drywood Termite Evidence

Drywood termites are more common in southern and coastal states. They don't need soil contact — they live entirely within the wood they consume.

• Frass. Small pellets that look like sawdust or coffee grounds, often found in small piles below infested wood. Drywood termite frass is distinctive — uniform in size, six-sided under magnification, and usually the same color as the wood being consumed.
• Kick-out holes. Tiny holes (1-2mm) in wood surfaces where termites push frass out of their galleries. Often found in window sills, door frames, and exposed beams.
• Blistering paint or wood surfaces. Termite galleries just below the surface can cause paint to bubble or wood to appear wavy.

The Inspection: Exterior First

Start outside and work your way in. The exterior perimeter tells you a lot about risk factors before you ever see evidence.

Foundation Perimeter Walk

Walk the entire foundation perimeter. You're looking for:

• Mud tubes on the foundation wall. Check the entire surface from grade level up to the sill plate or where the framing meets the foundation. Pay extra attention to corners, expansion joints, and where utility lines penetrate the foundation.
• Wood-to-soil contact. Siding, lattice, fence boards, deck posts — anything that gives termites a direct path from soil to wood without crossing an exposed foundation surface.
• Mulch depth. Mulch piled against the foundation creates moisture and conceals the bottom of the foundation wall. You can't inspect what you can't see. Mulch should be below the top of the foundation and pulled back from the siding.
• Grade and drainage. Poor grading that directs water toward the foundation creates the moisture conditions termites prefer. This overlaps with general home inspection findings.
• Stored wood and debris. Firewood stacked against the house, old lumber, cardboard boxes in covered porches. These are termite staging areas.

Exterior Wood Components

Probe exterior wood with an awl or screwdriver:

• Window sills and frames. Especially at the corners where moisture collects.
• Door frames and thresholds. Where the frame meets the foundation is a common entry point.
• Fascia and soffit. Look up — termites reach fascia boards through damaged or missing flashing.
• Deck ledger board. Where the deck attaches to the house is a moisture trap and a common infestation point.
• Garage door frames. Particularly where the frame meets the concrete slab.

Interior Inspection

Inside the house, you're limited by finished surfaces. You can't see behind drywall. But there are still plenty of accessible areas to evaluate.

Where to Focus

• Baseboards in basement or ground-floor rooms. Tap with a screwdriver handle. Hollow sound = probe further. Soft, easily penetrated wood = damage.
• Window and door trim. Particularly at ground-floor level. Check the bottom of frames where moisture and termites both enter.
• Closets and storage areas. These are often the last places homeowners look and the first places termites go undiscovered.
• Behind appliances and water heaters. Moisture sources that create favorable conditions. If you can access behind them, do.
• Around plumbing penetrations. Where pipes come through the slab or foundation wall, there's a gap. Termites exploit these gaps.

The Tap-and-Probe Technique

This is your primary tool for finding concealed damage:

1. Tap with the butt end of a screwdriver. Solid wood produces a sharp, resonant sound. Damaged wood sounds dull and hollow.
2. Probe with the tip. Push a flathead screwdriver or awl into the wood at a 45-degree angle. Sound wood resists. Termite-damaged wood gives way easily — the screwdriver sinks in with little resistance.
3. Look at the damage pattern. Subterranean termites eat along the grain, leaving layers. You'll see mud and soil in the galleries. Drywood termites leave clean galleries with frass pellets.

A word of caution: Don't probe finished wood surfaces in the living areas of the home unless you have reason to suspect damage. An unexplained screwdriver hole in a homeowner's oak door frame creates problems. Probe in concealed areas — closets, behind trim, unfinished spaces.

The Crawl Space: Where the Real Work Happens

If the house has a crawl space, this is where you'll find the most evidence. It's also the most physically demanding part of the inspection.

Preparation

• Proper PPE. Tyvek suit, knee pads, N95 respirator, headlamp, and a moisture meter. Crawl spaces are dirty, potentially contaminated, and occasionally host things worse than termites.
• Camera with flash. Your phone works, but a dedicated camera with macro capability is better for documenting small evidence like frass or mud tubes.
• Probing tool. A flathead screwdriver or a dedicated termite probe. Something you can tap and push into wood with.

What to Inspect in the Crawl Space

• Sill plate and rim joist. These are the first wood members above the foundation — and the first place subterranean termites reach. Probe the full perimeter. Pay particular attention where the sill plate sits on the foundation wall.
• Floor joists. Walk (or crawl) the length of each joist run. Tap and probe, especially at the bearing points where joists rest on beams or the sill plate.
• Support beams and posts. Center beams and their supports. If posts sit on concrete pads, check the base of each post for moisture damage and termite evidence.
• Subfloor. If visible, tap the subfloor from below. Damaged subfloor feels spongy and sounds dull.
• Plumbing penetrations. Where drain lines and water supply lines pass through the framing, there are gaps. Inspect around each penetration.
• Foundation walls from the inside. You may see mud tubes on the interior foundation surface that weren't visible from outside, especially in areas where exterior access was limited by landscaping or structures.

Moisture Readings

Use your moisture meter on framing members throughout the crawl space. Wood moisture content above 20% creates conditions favorable for both termites and wood decay fungi. Document elevated readings — they indicate risk areas even when no active infestation is present.

Documenting Damage

Documentation quality separates a useful termite report from one that creates more questions than it answers.

What Your Report Needs

1. Location. Specific enough that someone else can find the same spot. "Mud tubes observed on the south foundation wall, approximately 4 feet west of the southeast corner, extending from grade level to the sill plate."
2. Type of evidence. Mud tubes, frass, swarmers/wings, damaged wood, live termites. Be specific — "evidence of wood-destroying insects" is vague. "Subterranean termite mud tubes, active" tells the pest control operator exactly what they're dealing with.
3. Activity status. Active vs. inactive. Active mud tubes are moist, intact, and may contain live termites when broken open. Inactive tubes are dry, brittle, and empty. Previous damage with no current activity suggests past infestation — possibly treated, possibly not.
4. Extent of damage. How much wood is affected? Is the damage cosmetic (surface galleries only) or structural (significant cross-section loss in load-bearing members)?
5. Photos. Multiple photos from different angles. Include a reference object for scale — a coin, your probe, or a ruler. Wide-angle shots for location context, close-ups for evidence detail.

Structural vs. Cosmetic Damage

This distinction matters enormously for the transaction:

• Cosmetic damage: Surface galleries that haven't penetrated deeply into the wood. The structural integrity of the member is not compromised. Common in trim, non-structural sheathing, and the surface layer of framing members.
• Structural damage: Significant cross-section loss in load-bearing members — floor joists, beams, sill plates, studs. If you can push a screwdriver through a floor joist with one hand, that's structural damage.

When you're not sure: Recommend a structural evaluation. Don't guess at structural capacity — that's an engineer's job. Your job is to find the damage and document its location and apparent extent.

When to Refer to Pest Control

Every termite finding should include a recommendation for a licensed pest control operator (PCO) evaluation. But some findings are more urgent than others.

Immediate Referral (Before Closing)

• Active subterranean termites (live insects or moist, active mud tubes)
• Extensive damage to structural members
• Active drywood termite infestation (fresh frass accumulation)
• Multiple areas of activity suggesting widespread infestation

Evaluation Recommended (But Less Urgent)

• Inactive mud tubes with no visible damage
• Minor damage to non-structural components
• Previous treatment evidence (drill holes in slab, treatment stickers) with no current activity
• Conditions conducive to infestation (wood-soil contact, excessive moisture) but no current evidence

What to Tell Your Client

"I'm not a pest control operator, and treatment recommendations are outside my scope. What I can tell you is what I found, where I found it, and what it likely means. A licensed PCO will determine the treatment approach, provide a warranty, and handle the remediation."

This protects your scope, sets the right expectation, and gets the right professional involved.

Common Species by Region

Knowing your local termite species helps you know what to look for:

• Eastern subterranean termite (Reticulitermes flavipes): Most common species in the eastern US. Mud tubes, below-ground colonies, damage along the grain.
• Formosan subterranean termite (Coptotermes formosanus): Southeastern states. Larger colonies (millions vs. hundreds of thousands), more aggressive, can form above-ground colonies in wall voids if moisture is available.
• Western subterranean termite (Reticulitermes hesperus): Pacific coast states. Similar behavior to eastern subterranean.
• Drywood termites (Incisitermes and Cryptotermes species): Southern and coastal states. No mud tubes — live entirely in the wood. Look for frass and kick-out holes.
• Dampwood termites (Zootermopsis species): Pacific Northwest. Infest high-moisture wood only. Rarely a structural concern in maintained homes.

Speed Up Termite Documentation in the Field

Termite inspections are documentation-heavy. You're in a crawl space on your hands and knees, flashlight in your teeth, trying to photograph a mud tube while mentally noting the exact location for your report. Then you crawl 10 feet, find more evidence, and need to document that too.

Typing notes on your phone while wearing dirty gloves in a 3-foot-high crawl space isn't realistic. That's where voice documentation changes the game.

ReportWalk lets you narrate findings as you discover them. "Active mud tubes on the south sill plate, approximately six feet west of the access point. Tubes are moist, intact, extending from the foundation to the sill plate. Probing reveals soft wood in the sill plate, approximately two inches of penetration." That's your report note — captured in real time, hands-free, in the exact moment you're looking at the evidence.

When you're in a crawl space, your documentation tool needs to work as hard as you do. Voice-first reporting means your findings are captured accurately, in context, without slowing down your inspection.