Hi I'm in process of constructing a small house I want to live in. The house will be built on foundation of concrete pilots. Since I want to insulate the floor I am now in process of designing such barrier which will keep the insulation dry and pests (mouse or similar which would get into the crawlspace) away. I have now this construction in my mind (cut below):

===================== - subfloor
|| Joists, spaces filled with insulation
+++++++++++++++++++++ - one way vapor barrier
xxxxxxxxxxxxxxxxxxxxx - chicken wire

What do you think about this solution? Are there any better? I don't want to re-invent the wheel...

  • I don't know the size of pests in your area... just trying to find out what you have considered... Will they eat through insulation? – Solar Mike Aug 27 '19 at 13:20
  • They will definitely try. When nights gets colder, mice try to invade every space where they can hide from cold. You are right, that they are fairly small and I should focus on this. There are also voles, but they are rather seeking shelter underground and rats. Thanks. I'll try to look for better rodents barriers... – honza-kasik Aug 27 '19 at 13:27
  • Chicken wire is definitely not small enough to stop mice or even rats. Mice will get through a hole the size of a normal pencil. – Martin Bonner supports Monica Aug 28 '19 at 15:55
  • I think you also need a vapour barrier above the insulation. (The house air, being warm, will contain much water vapour. As it cools to ground temperature (~15C), it is likely to reach the dew point, and the water will condense out. – Martin Bonner supports Monica Aug 28 '19 at 15:57

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See above picture

I would add an electrical outlet in this crawl space and plug in a electronic pest repeller, to make any rodent's life miserable, if they found their way in there.

The other added reason to have at least one outlet down there is for your convenience, if you needed to plug in temporary lighting. Insure that this outlet is GFCI protected as well.


Short answer: Housewrap, then treated plywood.

I built many three- and four-season porches as additions. They were usually on posts. The routine was to frame the floor upside-down, apply housewrap, then install pressure-treated plywood and flip the whole thing over. Then we'd insulate and install the subfloor.


Chicken wire works great to hold the insulation in place. I would ask about the type of insulation you don’t want multiple vapor barriers that will end up trapping moisture. The only caution is make sure if you have copper pipes the chicken wire is not touching or in a few years you will end up with pinhole leaks wherever the wire touches the copper. But other than that chicken wire works great. Chicken wire will not stop even a large rat but if the space is insulated the critters don’t find the small leaks that attract them and if they do get in the insulation it is not ripped down , I have squirrels & mice after putting wire up the floors feel warmer and we have had fewer in the house, this could be from the electronic traps inside and dunk the rat in the barn. Still catch them weekly outside but have only got 1 inside the house since shortly after putting the wire up holding all the insulation in place that had come down, I don’t know how long ago it was put in but a large % had come down.

  • Chicken wire? As a mouse deterrent? That cannot be right. – Martin Bonner supports Monica Aug 28 '19 at 15:58
  • It holds the insulation in place no open gaps the mice find other ways in , works at keeping the insulation in place better than anything I have seen and that was the main question. – Ed Beal Aug 28 '19 at 17:34
  • Makes sense. Thanks – Martin Bonner supports Monica Aug 29 '19 at 5:05

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