Mice in Old House Basements: Doubles, Bungalows and Victorians

A tall brick Victorian with a turret and steep gables in Irvington, Indianapolis — Older Indy houses look great above ground. Below ground is where the gaps are.

Indianapolis has a lot of old houses, and they're a big reason people love neighborhoods like Irvington, Fountain Square and Broad Ripple. Second Empire and Italianate homes from the 1870s, bungalows from the 1910s, Tudor cottages from the 1920s, doubles on narrow lots. Almost all of them have a basement or a crawl space, and almost all of them have gaps.

This guide covers where mice usually get in and what to do about it.

Foundations

Older foundations are stone, brick or block, laid with mortar that crumbles over time. Mice don't need much. A gap where the mortar has fallen out, or where the foundation meets the wood sill plate, is plenty. Repointing the mortar and sealing the sill with metal mesh and sealant closes a lot of them.

Missing mortar in stone or brick foundations
Gaps at the sill plate and rim joist
Old coal chute doors and openings
Wood basement window frames that have rotted
Holes left from old gas, radiator and electrical lines

Doubles and Shared Basements

Doubles share a center wall, and often the basement isn't fully divided. Mice go back and forth. If you own one half, sealing your side helps, but working with the other owner helps more. Landlords with several doubles on a block should treat them all at once.

Crawl Spaces and Additions

Plenty of old houses have a crawl space under a back porch or a kitchen addition, and that's where mice often get in. Vents lose their screens, the access door doesn't latch, and the vapor barrier tears. Check those spots every fall. If the crawl space is a mess, see crawl space cleanup.

Got droppings, chewing or noises in the wall?

One call connects you with a licensed rodent company that works your side of town.

(317) 996-1254

Renovating? Do It Now

If you're opening walls or floors, that's the cheapest time to seal pipe holes and swap out dirty insulation. Having someone inspect first gives your contractor a map of the trouble spots. Sealing after the drywall goes back up costs more and reaches less.

Rodent Q&A

Should I fill the old coal chute?

Close it with metal or masonry if you don't use it. A wood door with gaps around it is an open invitation.

Can mice climb from the basement to the attic?

Yes, through wall cavities and around pipes and ducts. Droppings in the attic of an old house often started in the basement.