The Blog

Cold-Blooded Crawl Space Invaders: How To Keep Out Snakes

By Chuck Henrichsen on February 23, 2014

3917413454_90441e2dda_zMost people have a very healthy fear of snakes that unfortunately sometimes borders on phobia. The strange rasp of a snake hiss, the eerie creep of their legless bodies, and the nagging fear of poisonous fangs all contribute to the pervading hatred of snakes.

With this in mind, imagine with me that you’ve realized you need something out of one of the tightly sealed tubs in your crawl space. You put on some shoes and flick on the light while opening the trapdoor. As you descend into the gloomy chill and begin to peer at the labelled bins, you suddenly see the vanishing tip of a snake tail behind the plastic bin labelled ‘Christmas’. With a shriek, you shove the bin to the side and find yourself staring into dozens of unblinking eyes ….Time to call your local animal exclusion company!

Why do snakes go into crawl spaces?

Snakes will enter a building in search of a dark, damp and cool location in which to hibernate for the winter, or they are in search of small mammals for food. Snakes that are found in your crawl space or basement during the cold months are almost invariably drawn there for a safe warm place in which to den up for the winter; and when they do it can be in alarmingly large numbers. Some crawl spaces have been the hiding hole of over 70 snakes at one time, and occasionally host more than one species. Rattlesnakes often hibernate in groups.

By Accident:

Snakes have extremely poor sense of direction, so a snake that was happily snoozing in your foundation all winter may go the wrong way when trying to get back outside and find itself in your home. Crawl spaces that are not tightly sealed against the rest of the house are the most common culprits of finding snakes into the house.

To Have Babies:

Just to frighten us all a little more, some types of snakes will den up in crawl spaces or walls specifically to lay their eggs. Female snakes look for safe, warm places with lots of food for their babies. When the babies hatch, they don’t always make it back outside and may die, creating a truly foul odor that will pervade your home.


Snakes found in crawl spaces during spring and summer are most likely there to catch small animals that also are living in the dark underbelly of your home. If this is the case, read about deterring rodents from your home. The snakes won’t stick around where there’s nothing to eat.

How to Deter Snakes From Your Crawl space

The rules for discouraging snakes are very similar to the rules for discouraging rodents. Sealing any cracks in the foundation or walls that are ¼ inch or greater, covering all pipes and vents with mesh that has holes smaller than ¼ inch, and removing all ground hugging shrubbery and tall grasses from along the sides of the home will prevent snakes and rodents alike from wriggling in. Also check the clearance under doors and the sealing around plumbing or utility lines.

Have your crawl space properly cleaned and sealed by professionals. Installing the proper vapor barriers and insulation will help deter snakes from cozying up in your crawl space.

If you do have the displeasure of encountering a snake in your crawl space, it is best to have animal control remove it for you. While most snakes in the Seattle area are non-toxic, there is a moderate population of western rattlesnakes. These snakes are venomous and dangerous.

Remember, the best protection is prevention. If you’re unsure about the soundness of the seals in your crawl space or foundation, give us a call to come check it out for you.

crawl space critters

Chuck Henrichsen
President and CEO of Clean Crawls, Treasurer of E3 World Wide, proud husband and father.