Field guide
Where mice get in.
Brick, block, stucco and sound siding already keep mice out. The weak spots are where things meet: rooflines, pipes, wires, doors and seams. Here are the 8 we find on most houses, and how to close each one for good.
All 8, highlighted
- Roofline, soffit and fasciaMice are climbers. The roof edge is out of sight from the ground, and a small opening up there leads straight into the attic.How to fix it
- Roof returnsA roof return is the small boxed corner where a lower roof runs into a wall. It's often hollow inside, and it can open straight into the eaves.How to fix it
- Where building materials meetBrick, block, stucco and sound siding already keep mice out. The weak spots are the seams where two materials meet.How to fix it
- Pipes and AC line setsWhere the AC lines run through the wall, the hole is almost always bigger than the lines. A gap about the width of your finger is enough for a mouse.How to fix it
- Utility penetrationsEvery line that comes into the house, from power and gas to cable and phone, makes a hole. Those holes are rarely sealed well.How to fix it
- Weep holes and the foundation lineWeep holes are small openings at the bottom of brick and stone walls that let water drain out. They need covering, not sealing.How to fix it
- Garage door corners and bottom sealThe bottom corners of a garage door are where the seal wears, bends or stops short. If you can see daylight there, a mouse can get in.How to fix it
- Doors without sweepsIf you can see light under a door, a mouse can see the way in.How to fix it
Real houses
Real gaps, marked
These are the same entry points on real houses. The highlighter shows where a mouse would get in.
BeforeRoof return: a gnawed opening where the trim meets the shingles. Out of sight from the ground, and wide open.How to fix it: Roof return 
BeforeAC line set: the cover was packed with foam. It has crumbled away, and the gap around the lines is open.How to fix it: AC line set 
BeforeUtility lines: where a pipe runs up into the soffit, the panel has broken away and left an open hole.How to fix it: Utility lines 
BeforeFoundation line: lattice skirting looks closed from the yard, but every opening leads straight into the crawlspace.How to fix it: Weep holes 
BeforeFoundation line: gaps between the lattice slats run the whole length of the house.How to fix it: Weep holes 
BeforeGarage door corner: the bottom seal stops short of the jamb. If you can see daylight there, a mouse can get in.How to fix it: Garage door 
BeforeGarage door corner: droppings collected right where the bottom seal stops short. That gap is the way in.How to fix it: Garage door 
BeforeDoor sweep: the bottom seal is worn down and there is a gap under the door. If light shows through, a mouse can too.How to fix it: Door sweep
Before photos from real homes we've inspected, with the entry point marked in highlighter. Cropped so nothing identifies the house.
What a lasting fix is made of
Every guide comes back to the same idea: close the gap with something a mouse can't chew, and seal it in so there's no edge to grip.
- Stainless steel or galvanized hardware cloth, or exterior-grade metal.
- Sealed in with exterior-grade adhesives and sealants.
- Rodent-resistant door sweeps and garage door corner seals for doors.
- Covers, not fill, for weep holes and vents that need to breathe.
What doesn't last
- Spray foam alone. Mice chew right through it.
- Steel wool. It rusts and falls apart.
- Caulk alone over a big gap. It cracks and gets gnawed.
- Poison. It doesn't close the gap. Why not poison
Want us to look at your house?Send photos from your walk-around and we'll send back a custom plan: each gap marked, what to seal it with, and in what order.
Mouse-proof my house