The crawl space is the one part of the house nobody visits.
Rats noticed.
It’s dark and sheltered, and nobody ever comes down to bother them. For a Norway rat, a crawl space with a torn vent screen is prime real estate. The first hint is often a funny smell coming up through the heat registers. :(
Here’s how to get them out and make sure they don’t move back in.
TLDR: Rats get into crawl spaces through damaged vent screens and gaps in the foundation. Trap near the vents and along the foundation walls, then repair every screen and gap with heavy metal mesh. Don’t use poison down there, because the smell comes straight up through the floor. Want us to take a look? Call 604-559-9060.
Signs of rats in the crawl space
- Scratching or scurrying under the floor at night
- A musty or rotten smell coming through floor vents
- Torn or pulled-down vapour barrier
- Insulation pulled out from between the floor joists
- Droppings near the access hatch or along the foundation walls
- Burrows in a dirt floor or along the outside of the foundation
Not sure if it’s rats or mice? Here’s how to tell the difference.
How rats get into the crawl space
Crawl space vents are the most common way in we find. The original screens rust out or just weren’t strong enough to begin with.
Other entry points:
- Gaps where pipes and wiring pass through the foundation
- A loose or damaged access hatch
- Cracks in the foundation wall
- Burrows dug under the footing from outside
How to get rid of rats in the crawl space
1. Suit up before you go in
Crawl spaces with rats can be pretty grim. Wear gloves and a proper dust mask or respirator. Bring a bright flashlight.
Warning: If the crawl space is flooded or you smell gas, stay out and call a professional.
2. Trap near the vents and along the walls
Rats run along the foundation walls and in and out through the vents. Set snap traps on those routes, at right angles to the wall with the trigger facing it.
Bait with peanut butter and leave the traps unset for a few days so the rats get comfortable. Then set them and check them every day. A trap left for a week in a crawl space is not something you want to find.
3. Replace the vent screens
Swap flimsy screens for heavy-gauge hardware cloth or purpose-built metal vent covers. BC’s provincial guidance is to seal openings larger than about 6 mm (1/4 inch), so that’s the mesh size to aim for.
4. Seal the rest of the gaps
Close up gaps around pipes and wiring with metal mesh, sheet metal or concrete patch. Make sure the access hatch closes snugly.
If rats are burrowing under the footing, patching the wall won’t be enough. Our technicians dig a trench and bury an L-shaped wire mesh barrier so there’s nothing to tunnel under. The getting rid of rats outside guide covers burrows in more detail.
5. Clean up and repair
Don’t sweep up droppings. Spray them with disinfectant, let it soak for a few minutes and wipe them up.
Rats often trash the vapour barrier and insulation. If yours is torn or soiled, it’s usually best to remove it and start fresh.
Our pest clean-up team handles the dirty work, and our attic and crawlspace insulation services get the space back in shape.
Rats under your floor? We’ll trap them out and rat-proof your vents and foundation. Book a rat control inspection or call 604-559-9060.
Why poison is a bad idea in a crawl space
A rat that eats poison can take days to die, and it’ll usually do it somewhere tucked away. In a crawl space, that smell rises right through the floor and into your home.
We’re rodenticide-free. Trapping and sealing is cleaner, and you know when the job’s done.
Can rats get into the house from the crawl space?
Yes, and they often do.
Rats follow plumbing and wiring up through gaps in the subfloor and into the walls. Check under sinks and behind appliances for gaps where pipes come through the floor, and seal them too.
The verdict?
A crawl space rat problem is very fixable. It just takes a proper look at every vent and gap, plus a willingness to get a bit dirty.
If you’d rather not spend your Saturday on your belly under the house (fair enough), our technicians can do the whole job. Call 604-559-9060 or contact us online.
Westside pro tip
Tape a sheet of newspaper over a suspected entry hole from the inside. If it’s torn after a couple of nights, the hole is still in use. If it’s still intact after a week, you’re safe to seal it.
See related: How to get rid of rats in the basement | How to get rid of rats in the walls | How to get rid of rats permanently
FAQs
How do I know the rats are gone from my crawl space?
Traps will sit untouched for 1 to 2 weeks and you won’t find fresh droppings. Put a few paper towels down near the old routes. Clean paper after a week is a good sign.
What smell do rats leave in a crawl space?
Live rats leave a musty, ammonia-like smell from their urine. A dead rat smells sweet and rotten and is much stronger. Either one can drift up through floor vents into the house.
Should I replace the vapour barrier after rats?
If it’s torn or covered in droppings, yes. A damaged vapour barrier lets moisture into the crawl space, and a soiled one keeps the smell around. It’s usually replaced after the rats are gone and the entry points are sealed.