How to Insulate a Porch Floor – Best Practices and Materials

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I have a wooden screened-in porch on a cabin that I am remodeling, with approximately 30 inches from the ground to the bottom of the porch tongue-and-groove boards. I am considering insulating the porch, with the eventual goal of being able to place polycarbonate panels over the screen in the cold months to help with heat loss.

Before I replace the floor, I would like to add insulation board between the floor joists and staple wire mesh underneath to keep any critters from chewing up the exposed insulation board.

The caveat: this is near a river, and on rare occasion it does flood. I'm worried that placing the foam board would trap a large amount of moisture after a flood between it and the joists / tongue and groove that would keep it from drying out relatively quickly and therefor rot / mold.

Are there ways to mitigate this? Raising the structure isn't an option, but I'm unsure how/if it's possible to vent the individual compartments created by the insulation board / floor joists.

Best Answer

Indoor / outdoor carpet?

Maybe you can insulate by carpeting on top of the floor you have. There are lots of options. This will leave air movement under the porch as it is which I think is smart given flood risk. The indoor / outdoor carpet can be hung up to dry if the river floods, and replaced if it wears out or tastes change.

Anticritter mesh is a good idea, though.