How should openings larger than 1/4 inch be addressed to prevent rodent entry?

• A. Seal openings with steel hardware cloth, metal flashing, or cement; size reductions as appropriate.
• B. Ignore them.
• C. Put bait near it.
• D. Install fans.

Answer: (A)

Physical exclusion is the priority: when openings exceed 1/4 inch, they must be blocked with materials rodents cannot gnaw through. Use steel hardware cloth with a mesh at or finer than 1/4 inch to cover vents and gaps, metal flashing to seal joints and edges, and cement or mortar to fill larger cracks in foundations or walls. If possible, reduce the size of the openings so entry is no longer possible, and ensure coverings are securely installed to prevent chewing or prying.

This approach creates a durable barrier that stops entry rather than relying on attractants or deterrents. Bait placed near an opening doesn’t prevent access and can complicate control, and fans don’t provide a true barrier to entry.