Rats in the Crawlspace? – What to Look For

By Chris Williams on May 30, 2016.

I think that some animal is living in our crawlspace. I hear noises sometimes and my wife thought she saw a rat around the foundation of our house. The rat or whatever never seems to be there when I check. What else should I look for? N. O., Nottingham, NH

Below are some hints that something may be living in your crawlspace. Some of these same signs could apply to another animal as well, so a professional pest control inspection can determine exactly who is living there.

  1. There may be burrows – If your crawl has a dirt floor and especially if there is loose backfill soil, you might find burrows dug into the soil. There may be a collar of loose, recently excavated dirt around the opening (see Could Those Be Rat Holes?).
  2. There may be poop – A Norway or brown rat produces 40-50 pellet-like droppings a day that will usually be concentrated in a few areas. A pest control professional can use the type of poop found to identify the animal in question and will use an ultraviolet light to detect animal urine.
  3. There may be rubmarks – Look for dark, greasy rubmarks from a rat’s fur around the opening or vent where it enters the crawl, or along walls or other surfaces along its travel route.
  4. There may be loose, sagging insulation – If your crawl has standard insulation, you may find evidence of rats nesting behind it. The insulation may be ripped off of the staples or nails, leaving it sagging at the nest site.
  5. There may be gnaw marks – Rats will chew on many items including wood, aluminum, lead, plastic, and mortar. They will gnaw to make an entrance hole bigger. Check the floor joists and wall studs for tooth grooves and wood shavings beneath. Be sure to check electrical wiring for any evidence of gnawing.
  6. There may be footprints – If your crawl has a dirt or dusty floor, shine your flashlight parallel to the ground, particularly along the foundation wall. Any rat tracks there should be visible. Active rat runways in a dirt crawl will be seen as clean, packed paths, free of debris (see What Does a Rat’s Runway Look Like?).

If you suspect a crawlspace varmint, you should have a pest control inspection to determine whether the resident is a rat, cat, raccoon, or something else. No matter the pest, our team can humanely trap it out and then seal or repair any openings that the animal is using to get into the crawlspace. We’ve been doing this kind of work for 30 years. Give Colonial Pest a call!

Photo Credit: NY State IPM Program at Cornell University | CC BY 2.0



We’re not satisfied until you are. Learn More