Rat Slab

Oldest daughter has had some issues with rats in her crawl space. Insulation is torn-up, no other real damage from what she can tell me. Contacted an exterminator and they recommend installing a “rat slab” ie 2-3 inches of concrete in addition to replacing all the insulation and trying to fix any obvious sites of entry. She has about 1000 sf of crawl. Price quoted is $13,000. Plus, to get the guarantee, she has to sign up for at least a year of every two month checks at $120 a pop.

We told her to get several more bids. Both treatment now and annual service. Also wonder about crawl space companies, it they can seal it up at a better price.

Questions for this group is if anyone has experience with a rat slab and is it really worth it? Any experience good or bad? I assume she’ll have to have a vapor barrier down on top of it.

Also, any thoughts on the routine exterminator visits? I’ve always just dealt with it myself without any big problems. Difficulty is that she has regular city neighbors (other houses 15-20 feet from hers) and even if she does everything right, you can’t make neighbors do the right thing.

Thanks for thoughts,


  • Seems expensive! For the slab and for the “guarantee”.

  • A DIY would be to buy a few bags of concrete… from time to time… that sets in the presence of moisture. Preferably do a quick mix (instead of dumping the dry mix (because of my vapor barrier comment below) and dump it/spread it/smooth it in a corner and gradually make it grow. A lengthy process, but certainly cheaper. Do small sections at a time. Eventually, there is no entry point for rats from below. Make sure there is a sump pump or drain or you’ll have another problem. :wink:

  • You want the vapor barrier UNDER the concrete, not on top of it.

Rule Breaker Home Fool
He is no fool who gives what he cannot keep to gain what he cannot lose.


How about a crawl space cat?
Or rat terrier?

I’ve a cousin whose 10 lb terrier dogs have access to their crawl space, which the dogs seem to enjoy.


No experience with rat slabs. But we had the “opposite” problem – rats in our attic. We found a local ‘wildlife control’ company. They set traps up in our attic, and sealed off all the openings that a rat could use to enter. Then they came back ever week or two and emptied and reset the traps, until there were no dead rats.

But the rats came back a few years later, so we called them again and went through the same process. Either the rats had found a new opening, or the company originally missed one. Anyway, that was about 3 years now, and no new rats since (fingers crossed).

Total for both jobs was a bit over $1000, which is a heck of a lot cheaper than the “rat slab” quote. If she can find a company specializing in wildlife control, I’d recommend at least getting a quote from them, and maybe trying that out before investing in a rat slab.



Did they explain how a concrete slab would prevent the rats? Seems like the rats are getting under the house through some openings somewhere, don’t see how the new slab would prevent that.


Rats burrow as well. So if this is not a stem wall foundation, they can burrow right into a nice relatively warm, and cozy location.


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