Pest-proofing a Michigan home in fall takes about four hours of work, must be done before mid-October, and prevents the six most common indoor pests of winter: mice, rats, stink bugs, box elder bugs, Asian lady beetles, and overwintering spiders. The checklist below covers exterior sealing, garage seals, vent screens, weatherstripping, gutter and vegetation work, and proper firewood storage.
The 10-Step Fall Pest-Proofing Checklist
Work through these in order on a dry, mild day. Materials: stainless-steel mesh, copper wool, exterior-grade sealant, garage door corner seals, replacement weatherstripping, gutter cleaning supplies, sealed storage containers, a flashlight, and a ladder.
- Exterior gap survey. Walk the full perimeter at dusk. Seal every gap larger than 1/4 inch with mesh + sealant. (See the full mouse exclusion guide for the 7 most common entry points in Metro Detroit homes.)
- Garage door corner seals and bottom sweep. The corners between the door and the side jambs almost always leak. Install rodent-proof corner-seal brushes and replace the bottom sweep if it shows daylight when the door is closed.
- Vent screens. Replace any damaged dryer vent hood with a metal-mesh hood. Screen attic gable vents, soffit vents, and ridge vents with 1/4-inch hardware cloth where mesh is missing or damaged.
- Weatherstripping replacement. Inspect every exterior door and window. Replace any weatherstripping that no longer compresses. Add door sweeps where light is visible at the threshold.
- Gutter cleaning + downspout extension. Clogged gutters spill water against the foundation, which softens wood and feeds carpenter ants. Clean gutters and extend downspouts 5 feet away from the foundation.
- Trim vegetation 18 inches from foundation. Mice and other pests use shrubs touching the house as a bridge. Trim back to maintain an 18-inch clear gap on all sides.
- Move firewood 20 feet from house and off ground. Firewood stacked against the house is a rodent and carpenter-ant hotel. Move it at least 20 feet away and store it on a rack at least 6 inches off the ground.
- Inspect attic and crawlspace. Look for droppings, nesting material, gnaw marks, or stink bug aggregations. Catching evidence now prevents wall-void breeding through winter.
- Declutter garage and basement. Cardboard boxes, paper bags, and clutter give pests harborage. Switch to sealed plastic containers; donate or discard cardboard.
- Schedule professional perimeter treatment. Exterior treatment applied to sunny south and west walls in late September catches box elder bugs, stink bugs, and Asian lady beetles before they enter the wall voids. The BTR Seasonal Package at $550/year includes a fall exterior treatment.
Why the Mid-October Deadline Matters
Michigan's pest year is driven by temperature thresholds, not the calendar date. When overnight lows drop below 50 degrees Fahrenheit — usually the first week of October — mice begin moving indoors. Brown marmorated stink bugs, box elder bugs, and Asian lady beetles cluster on sunny south and west walls on warm October afternoons and squeeze inside through any unsealed gap they can find. Exterior treatment applied after they enter the wall voids is far less effective than treatment applied before.
See the October entry in the Michigan Seasonal Pest Calendar for the full migration timeline, and the fall pest control guide for what BTR's fall service covers.
Which Pests This Checklist Stops
House Mouse
Peak entry: first week of October.
Norway Rat
Same window, larger gap tolerance.
Brown Marmorated Stink Bug
Cluster on sunny walls, then enter.
Box Elder Bug
Same pattern as stink bugs.
Asian Lady Beetle
Aggregations on south-facing walls.
Spiders
Wolf and cellar spiders move indoors to mate.
After You Complete the Checklist
- Schedule professional fall service or the seasonal package. Even a perfect DIY checklist still benefits from one professional exterior treatment to deal with stink bugs and box elder bugs before entry.
- Set up indoor monitoring. Multi-catch traps in the garage and basement (set but unbaited) catch any mice that beat the deadline.
- Mid-November walk-through. Re-inspect every gap you sealed. Building settlement can open new ones.
- Plan winter watch. See the winter pest control guide for what to monitor December through February.
Frequently Asked Questions
When should I pest-proof my Michigan home for winter?
Complete the checklist before mid-October. The deadline is when overnight lows drop below 50 degrees Fahrenheit (usually the first week of October), which is when mice begin moving indoors. Stink bugs, box elder bugs, and Asian lady beetles enter the same window.
Can I do fall pest-proofing myself?
Most of the 10 steps are DIY: gap sealing, garage seals, vent screening, weatherstripping, gutter work, vegetation trimming, firewood relocation, attic inspection, and decluttering. The professional exterior treatment in step 10 is the one piece DIY cannot match because retail sprays do not include the residual chemistry that catches returning workers.
How long does fall pest-proofing take?
About four hours for a typical Metro Detroit home, broken into roughly one hour outside (gap survey + sealing), one hour at the garage and vents, one hour at gutters and vegetation, and one hour inside (attic + basement + decluttering). Most homeowners do it across two weekends.
What is the most important step on the list?
The exterior gap survey (step 1). Mice need any gap larger than 1/4 inch. Rats need any gap larger than 1/2 inch. Closing every entry point larger than a dime is what actually stops fall migration. The other steps reinforce the seal but the seal is the foundation.
Do I still need professional pest control if I complete the checklist?
You will significantly reduce indoor pest pressure but not eliminate it. The professional exterior treatment in step 10 is the missing piece for stink bugs, box elder bugs, and Asian lady beetles — treatment applied to sunny walls before entry is far more effective than interior treatment after they are in the walls.
Will fall pest-proofing keep all pests out year-round?
Fall pest-proofing stops fall migration. Spring brings a different set of pests (carpenter ants, queen wasps, pavement ants) that need their own treatment window. The Michigan Seasonal Pest Calendar covers what each season requires.
Need a Pre-Winter Pest Inspection?
Free inspection. Licensed Michigan applicators. 90-day warranty on most services.