Trim trees so branches don't touch the house or roof. Ants will frequently gain access to the house by crawling up old, rotting trees onto your roof. Check the foundation for holes too. Follow-up after an infestation by treating the foundation of your home and cracks near the spot where you found a nest. Consider a benign treatment like sweeping diatomaceous earth and a natural insecticide like pyrethrum, into cracks and along the trails the ants followed.
Diatomaceous earth is composed of sharp crystals that cut the ants' exoskeletons.
The insects desiccate and die. Contact the university extension service for brochures about ant control. It is bulletin number NCR 531 and contains close-up photos of common household ants. Lake maps showing shoreline features, depths and vegetation for many of Wisconsin's frequently fished lakes are available at DNR regional offices and service centers. Several private companies have taken these maps, added color and other details, printed them on waterproof paper and bound them into books.