OSU Entomology’s Joe Boggs says fall insects seek warm spots between walls, around window casings, in door jambs and in attics, and he suggests shop vacuums and light traps for removal. This checklist turns that advice into a room-by-room and outside-in list a Columbus homeowner can work through before the cold weather arrives.
Key takeaways
- Fall insects look for warm spots between walls, around window casings, in door jambs and in attics.
- A shop vacuum and a light trap are the removal tools OSU suggests for insects inside.
- Walk the outside first on a bright day and mark each gap with tape.
- Check the door sweeps, the window casings and the attic hatch.
- Repeat the check after the first hard frost and again in spring.
- Sealing is the step that reduces the number that come in each year.
Step 1: Walk the outside on a bright day
Start at the front of the house and walk around it, marking each window and door frame, each siding joint, each soffit vent and each penetration for a cable, pipe or vent.
A bright day shows light through a gap more clearly than a cloudy one. Hold the flashlight behind a frame on the inside while a helper watches from outside, or take the outside walk first and check the inside afterward. Either way, mark each gap with a piece of painter’s tape so it can be found again.
Look at the joints where the siding meets the trim, the corners of each window and the places where a cable or a vent passes through the wall. Note any screen that is torn, bent or missing, and any soffit board that has opened at a joint.
Step 2: Check the window casings and the door jambs
OSU’s entomologist names window casings and door jambs as warm spots insects use. Check the caulk at each casing, the seal around each door and the gap under the door sweep.
The window casing is where two or three pieces meet, and the caulk at the corners shrinks and cracks over time. A fingertip can feel a draught at a casing that a light does not show clearly. Re-caulk any open joint with a product for exterior use.
The door jamb is a gap that many homeowners overlook. A worn sweep or a threshold that has moved leaves a gap along the bottom or the side of the door, and a warm wall void behind the jamb is an attractive place to settle. Replace a worn sweep and check the threshold for a space.
Step 3: Check the attic and the upper rooms
OSU’s account names attics as warm spots, so the attic is part of the checklist. Check the attic hatch for a tight fit, the vents for screens and the eaves for gaps.
A loose attic hatch lets warm air and insects move between the attic and the house. Fit a foam strip around the hatch edge and make sure it closes firmly. The vents should have intact fine screens, and the eaves should show no open joint.
In the upper rooms, check the closets and the corners near the ceiling for any insect that has moved down from the attic. A dated note of the sightings tells the technician where to look first on a visit.
Step 4: Remove the insects already inside
Use a shop vacuum for insects in the window tracks, curtain folds and corners, as OSU suggests. Empty the vacuum outdoors into a sealed bag. Light traps can catch insects that move toward a light in the warm hours.
A shop vacuum is quick and leaves no stain. Work along each window track and each curtain fold, and seal the bag once the room is clear. Do not crush the insects by hand, because some leave a stain or an odour behind.
A light trap is placed in a room where insects gather and left for a few days. It catches the insects that move toward the light. The trap should be emptied and its contents discarded in a sealed bag. The trap is a way to check the number, not a way to close a route.
Step 5: Keep a dated record and check again
Write down what was sealed and what was found, with dates. Repeat the check after the first hard frost and again in the spring, when the screens and vents can be checked after the winter.
A short list kept on the house file is the record that makes the next season quicker. Note each gap sealed, each screen replaced and each room where insects were found, with the date.
The first hard frost is a good time to check the outside, because the cold can open a joint that was sealed in warm weather. The spring check looks at the screens and vents, and any damage from the winter is added to the list.
A homeowner who finishes the list early can run the outside walk again in a week, when the first pass has been fixed. The second walk often finds one more gap that was hidden by the first repair, and it is worth recording.
When should a professional be called?
Call a professional when the gaps are high, when an insect is found that cannot be identified, or when a sign suggests a source inside a wall. A technician can seal what the homeowner cannot reach and identify what the homeowner has found.
A gap high on a soffit or a roof line is a reason to call, because a ladder on uneven ground is a safety risk. A technician with the right equipment can seal it from a stable position, and the report records the work.
An insect that the homeowner cannot identify should be kept in a sealed bag and shown to the technician. A sign that suggests an insect inside a wall, such as a steady stream from a wall at night, is a reason to book an inspection rather than to spray the wall.
What should a homeowner do with the soffit vents?
Check each vent for a fine screen that is intact and fitted. A missing or torn screen is an open route, and the replacement is quick and inexpensive.
A soffit vent keeps the attic ventilated, and its screen is what stops insects from using it. The screen should be a fine mesh, fitted to the vent and free of tears. A bent or missing screen is replaced at once, and the replacement is noted on the list.
A vent that is blocked by paint, insulation or debris is not doing its job. Clear the vent carefully, without damaging the screen, and check that air can still move through it.
How should a homeowner check the basement?
Check the basement window wells, the sill, the rim joist and any penetration for a cable, pipe or vent. The gap at each is marked and sealed with a material suited to the surface.
A window well holds leaves and water against the wall, and the frame at the well is a route. Clear the well, check its drain and seal the frame if it lets light through.
The rim joist is the wood that sits on top of the foundation wall, and it has many small gaps. A flashlight along the joist shows the openings. The gaps are sealed with foam or caulk and covered where they are exposed to sun.
What if a gap cannot be reached?
A gap that cannot be reached safely is noted on the list and checked by a technician with the right equipment. The homeowner should not reach across a gap from an unstable position.
A gap high on a soffit or behind a shrub is a reason to call. The technician uses a stable ladder or a platform and records the gap as sealed or not reached.
A gap behind a fixed cabinet or a heavy appliance may not be reachable at all. The report says so, and the homeowner can decide whether the cabinet should be moved.
How does a homeowner keep the list up to date?
Use the same order each season, date each item and add any new gap as soon as it appears. A short list kept with the house records is the easiest way to see what has changed.
A seasonal date in late summer and spring is enough for most homes. Walk the checklist in the same order, so nothing is missed. A new feature, such as a shed or a new window, goes on the list the first time it is seen.
Share the list with the technician on the visit. A dated list gives the inspector a clear starting point, and it shows which items were already done and which were not.
Frequently asked questions
Is a checklist enough to stop fall insects?
It reduces the routes and the numbers that come in, which is the lasting step. A checklist does not guarantee that no insect will enter, and a few may find a gap that nobody has found yet.
When is the best time to start?
Late summer, before the first warm autumn days. Sealing done then has time to be tested before the cold months.
Do I need a light trap?
A light trap helps you see how many insects are inside and where they gather. It does not close a route, so the sealing still comes first.
Does the checklist cover the basement?
Yes, in its basement step, where the window wells, the sill and any penetration are checked in the same way as the outside walk.
What is the cheapest step with the biggest effect?
Replacing worn door sweeps and torn vent screens is usually the cheapest step with a visible effect. Re-caulking a window casing is the next, and the report gives the order for a particular house.
Should I check the chimney?
Yes, from the outside on the walk. A chimney cap or a flue collar with a gap is a route that is easy to miss, and the technician notes it for repair by a qualified person.
How long does the whole checklist take?
Most homeowners can complete the outside walk and the inside check across a weekend. The sealing itself can take a little longer, and it can be spread over several weekends if needed.
Should I seal before or after I vacuum?
Vacuum the insects inside first, so they are not sealed into a wall, then seal the gaps. Sealing with a bug inside a wall traps it, and it comes out later on a warm day.
Sources
- Ohio State University Entomology, comments by Joe Boggs on fall invaders, as reported in local news (ohiostate.edu)
- Ohio State University Extension (ohioline.osu.edu)
This guide is general information for Franklin County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.