I've got a home with a dirt crawlspace -- post and beam holding up the house, with the piers for the posts in the crawlspace of course. I had someone come look at it recently to clean it up -- I've had rodents in there recently. There is currently NO INSULATION in the crawlspace -- none whatsoever. Crawlspace is about 1000 sq. feet, flat.

The guy who came to look at the crawlspace said that he can clean it up (the poly was dragged all over the place), install traps and seal off entrances. But he also said for more money he could just pave the entire crawlspace to keep animals from burrowing and tunneling under.

Seems to me like if the crawlspace is dirt, it should probably stay dirt. Something doesn't sound right about paving it. Are there downsides to paving what is currently a dirt crawlspace?

1 Answer 1


By paving I assume you mean pouring concrete. The only downside is the cost and future modifications. If you want to run a new drain line, for example, you need to break up the concrete versus just digging up some dirt.

Generally I would say homeowner and future buyers would prefer to see a concrete floor since it just looks better.

  • Thanks for the response. Yes, I mean pouring concrete. I guess I'm worried b/c why wouldn't they have just poured it in the first place? There's no reason that dirt works better for a crawlspace besides the future-modifications reason? I thought maybe b/c of moisture problems it's better to have dirt since maybe it'll drain or something.
    – Trevor
    Apr 21, 2014 at 21:36
  • 2
    Dirt doesn't work better, it was just there and it's free. There should be 6-12" of gravel under the concrete to allow drainage and a vapor barrier between the two. Having the gravel without concrete would still be better than dirt.
    – Steven
    Apr 22, 2014 at 0:52
  • 4
    The paving that is written about is called a rat slab. A very rough pour about 2" thick, I have had them spec'd in homes I have built and seen them in older homes I have worked on
    – Jack
    Apr 22, 2014 at 3:16
  • Rat Slab! Perfect. Now that I know what to search for, tons of stuff comes up. Thanks Jack.
    – Trevor
    Apr 22, 2014 at 5:53

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