Closed cell spray foam

Will closed cell insulation sprayed under a mobile home seal out mice and bugs?

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mobile home seal out mice and bugs

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It would probably do a good job of that for a while. But if there is a healthy rodent population in the area, they will eventually chew a hole somewhere. Certainly they will chew through if the infestation is active.

But foaming the underside of a floor on a raised house terrifies me. If you have a leak anywhere above the floor level, the damage could be catastrophic depending on how long the leak has gone on undetected. If the leaking water can't down through the foam and onto the ground, it will go sideways potentially for several rooms. This may require the flooring and subfloor to be replaced. I personally would never foam the underside of a raised home. Leaks aren't an if but a when. Hell even a gallon of water spilled and not immediately cleaned up can seep between the flooring and subflooring and stay there for....ever.

If you aren't in a low area with poor drainage, the best and most expensive option is an insulated underpinning with good vapor barrier on the dirt. This effectively makes the unside of the home a conditioned area. But of course this isn't an option if in a low area and can't keep rain water from flowing under house. Sorry Cajuns.